Associate Professor of Chemistry Matthew Kanan develops new catalysts and chemical reactions for applications in renewable energy conversion and CO2 utilization. His group at Stanford University has recently developed a novel method to create plastic from carbon dioxide and inedible plant material rather than petroleum products, and pioneered the study of “defect-rich” heterogeneous electro-catalysts for converting carbon dioxide and carbon monoxide to liquid fuel.

Matthew Kanan completed undergraduate study in chemistry at Rice University (B.A. 2000 Summa Cum Laude, Phi Beta Kappa). During doctoral research in organic chemistry at Harvard University (Ph.D. 2005), he developed a novel method for using DNA to discover new chemical reactions. He then moved into inorganic chemistry for his postdoctoral studies as a National Institutes of Health Postdoctoral Research Fellow at the Massachusetts Institute of Technology, where he discovered a water oxidation catalyst that operates in neutral water. He joined the Stanford Chemistry Department faculty in 2009 to continue research into energy-related catalysis and reactions. His research and teaching have already been recognized in selection as one of Chemistry & Engineering News’ first annual Talented 12, the Camille Dreyfus Teacher-Scholar Award, Eli Lilly New Faculty Award, and recognition as a Camille and Henry Dreyfus Environmental Mentor, among other honors.

The Kanan Lab addresses fundamental challenges in catalysis and synthesis with an emphasis on enabling new technologies for scalable CO2 utilization. The interdisciplinary effort spans organic synthesis, materials chemistry and electrochemistry.

One of the greatest challenges of the 21st century is to transition to an energy economy with ultra-low greenhouse gas emissions without compromising quality of life for a growing population. The Kanan Lab aims to help enable this transition by developing catalysts and chemical reactions that recycle CO2 into fuels and commodity chemicals using renewable energy sources. To be implemented on a substantial scale, these methods must ultimately be competitive with fossil fuels and petrochemicals. With this requirement in mind, the group focuses on the fundamental chemical challenge of making carbon–carbon (C–C) bonds because multi-carbon compounds have higher energy density, greater value, and more diverse applications that one-carbon compounds. Both electrochemical and chemical methods are being pursued. For electrochemical conversion, the group studies how defects known as grain boundaries can be exploited to improve CO2/CO electro-reduction catalysis. Recent work has unveiled quantitative correlations between grain boundaries and catalytic activity, establishing a new design principle for electrocatalysis, and developed grain boundary-rich copper catalysts with unparalleled activity for converting carbon monoxide to liquid fuel. For chemical CO2 conversion, the group is developing C–H carboxylation and CO2 hydrogenation reactions that are promoted by simple carbonate salts. These reactions provide a way to make C–C bonds between un-activated substrates and CO2 without resorting to energy-intensive and hazardous reagents. Among numerous applications, carbonate-promoted carboxylation enables the synthesis of a monomer used to make polyester plastic from CO2 and a feedstock derived from agricultural waste.

In addition to CO2 chemistry, the Kanan group is pursuing new strategies to control selectivity in molecular catalysis for fine chemical synthesis. Of particular interest in the use of electrostatic interactions to discriminate between competing reaction pathways based on their charge distributions. This effort uses ion pairing or interfaces to control the local electrostatic environment in which a reaction takes place. The group has recently shown that local electric fields can control regioselectivity in isomerization reactions catalyzed by gold complexes.

Academic Appointments

Honors & Awards

  • Selected one of first annual Talented 12, Chemistry & Engineering News (2015)
  • Camille Dreyfus Teacher-Scholar Award, Camille & Henry Dreyfus Foundation (2014)
  • Hellman Faculty Scholar Award, Hellman Fellows Program (2013)
  • Camille and Henry Dreyfus Environmental Mentor, Camille & Henry Dreyfus Foundation (2012)
  • Thieme Journal Award, Thieme Medical Publishers (2010)
  • Eli Lilly New Faculty Award, Eli Lilly and Company (2009)

Boards, Advisory Committees, Professional Organizations

  • Editorial Advisory Board Member, ACS Central Science (2015 - Present)

Professional Education

  • Postdoc, Massachusetts Institute of Technology, Water-Oxidation Catalysis (2005)
  • PhD, Harvard University, Organic Chemistry (2005)
  • BA Summa Cum Laude, Rice University, Chemistry (2000)

Stanford Advisees

All Publications

  • A Semicrystalline Furanic Polyamide Made from Renewable Feedstocks. Journal of the American Chemical Society Woroch, C. P., Cox, I. W., Kanan, M. W. 2022


    Semi-aromatic polyamides (SAPs) synthesized from petrochemical diacids and diamines are high-performance polymers that often derive their desirable properties from a high degree of crystallinity. Attempts to develop partially renewable SAPs by replacing petrochemical diacids with biobased furan-2,5-dicarboxylic acid (FDCA) have resulted in amorphous materials or polymers with low melting temperatures. Herein, we report the development of poly(5-aminomethyl-2-furoic acid) (PAMF), a semicrystalline SAP synthesized by the polycondensation of CO2 and lignocellulose-derived monomer 5-aminomethyl-2-furoic acid (AMF). PAMF has glass-transition and melting temperatures comparable to that of commercial materials and higher than that of any previous furanic SAP. Additionally, PAMF can be copolymerized with conventional nylon 6 and is chemically recyclable. Molecular dynamics (MD) simulations suggest that differences in intramolecular hydrogen bonding explain why PAMF is semicrystalline but many FDCA-based SAPs are not.

    View details for DOI 10.1021/jacs.2c11806

    View details for PubMedID 36573894

  • Operando Nanoscale Imaging of Electrochemically Induced Strain in a Locally Polarized Pt Grain. Nano letters Sheyfer, D., Mariano, R. G., Kawaguchi, T., Cha, W., Harder, R. J., Kanan, M. W., Hruszkewycz, S. O., You, H., Highland, M. J. 2022


    Developing new methods that reveal the structure of electrode materials under polarization is key to constructing robust structure-property relationships. However, many existing methods lack the spatial resolution in structural changes and fidelity to electrochemical operating conditions that are needed to probe catalytically relevant structures. Here, we combine a nanopipette electrochemical cell with three-dimensional X-ray Bragg coherent diffractive imaging to study how strain in a single Pt grain evolves in response to applied potential. During polarization, marked changes in surface strain arise from the Coulombic attraction between the surface charge on the electrode and the electrolyte ions in the electrochemical double layers, while the strain in the bulk of the crystal remains unchanged. The concurrent surface redox reactions have a strong influence on the magnitude and nature of the strain changes under polarization. Our studies provide a powerful blueprint to understand how structural evolution influences electrochemical performance at the nanoscale.

    View details for DOI 10.1021/acs.nanolett.2c01015

    View details for PubMedID 36541700

  • Improving the Energy Efficiency of CO Electrolysis by Controlling Cu Domain Size in Gas Diffusion Electrodes ACS ENERGY LETTERS Rabinowitz, J. A., Ripatti, D. S., Mariano, R. G., Kanan, M. W. 2022: 4098-4105
  • Carbonate-catalyzed reverse water-gas shift to produce gas fermentation feedstocks for renewable liquid fuel synthesis CELL REPORTS PHYSICAL SCIENCE Li, C. S., Frankhouser, A. D., Kanan, M. W. 2022; 3 (9)
  • Hypophosphite addition to alkenes under solvent-free and non-acidic aqueous conditions. Chemical communications (Cambridge, England) Huang, Z., Chen, Y., Kanan, M. W. 1800


    Hypophosphite adds to alkenes in high yields under solvent-free conditions at elevated temperature, including alpha,beta-unsaturated carboxylates. The reaction proceeds by a radical mediated pathway. Hypophosphite addition is also effective under non-acidic aqueous conditions employing radical initiators. These methods complement other hypophosphite addition reactions and simplify the synthesis of polyfunctional H-phosphinates.

    View details for DOI 10.1039/d1cc06831h

    View details for PubMedID 35060983

  • A framework for automated structure elucidation from routine NMR spectra. Chemical science Huang, Z., Chen, M. S., Woroch, C. P., Markland, T. E., Kanan, M. W. 2021; 12 (46): 15329-15338


    Methods to automate structure elucidation that can be applied broadly across chemical structure space have the potential to greatly accelerate chemical discovery. NMR spectroscopy is the most widely used and arguably the most powerful method for elucidating structures of organic molecules. Here we introduce a machine learning (ML) framework that provides a quantitative probabilistic ranking of the most likely structural connectivity of an unknown compound when given routine, experimental one dimensional 1H and/or 13C NMR spectra. In particular, our ML-based algorithm takes input NMR spectra and (i) predicts the presence of specific substructures out of hundreds of substructures it has learned to identify; (ii) annotates the spectrum to label peaks with predicted substructures; and (iii) uses the substructures to construct candidate constitutional isomers and assign to them a probabilistic ranking. Using experimental spectra and molecular formulae for molecules containing up to 10 non-hydrogen atoms, the correct constitutional isomer was the highest-ranking prediction made by our model in 67.4% of the cases and one of the top-ten predictions in 95.8% of the cases. This advance will aid in solving the structure of unknown compounds, and thus further the development of automated structure elucidation tools that could enable the creation of fully autonomous reaction discovery platforms.

    View details for DOI 10.1039/d1sc04105c

    View details for PubMedID 34976353

    View details for PubMedCentralID PMC8635205

  • A High-T-g Polyamide Derived from Lignocellulose and CO2 MACROMOLECULES Woroch, C. P., Lankenau, A. W., Kanan, M. W. 2021; 54 (21): 9978-9983
  • Microstructural origin of locally enhanced CO2 electroreduction activity on gold. Nature materials Mariano, R. G., Kang, M., Wahab, O. J., McPherson, I. J., Rabinowitz, J. A., Unwin, P. R., Kanan, M. W. 2021


    Understanding how the bulk structure of a material affects catalysis on its surface is critical to the development of actionable catalyst design principles. Bulk defects have been shown to affect electrocatalytic materials that are important for energy conversion systems, but the structural origins of these effects have not been fully elucidated. Here we use a combination of high-resolution scanning electrochemical cell microscopy and electron backscatter diffraction to visualize the potential-dependent electrocatalytic carbon dioxide [Formula: see text] electroreduction and hydrogen [Formula: see text] evolution activity on Au electrodes and probe the effects of bulk defects. Comparing colocated activity maps and videos to the underlying microstructure and lattice deformation supports a model in which CO2 electroreduction is selectively enhanced by surface-terminating dislocations, which can accumulate at grain boundaries and slip bands. Our results suggest that the deliberate introduction of dislocations into materials is a promising strategy for improving catalytic properties.

    View details for DOI 10.1038/s41563-021-00958-9

    View details for PubMedID 33737727

  • Carbonate-promoted C-H carboxylation of electron-rich heteroarenes CHEMICAL SCIENCE Porter, T. M., Kanan, M. W. 2020; 11 (43): 11936–44

    View details for DOI 10.1039/d0sc04548a

    View details for Web of Science ID 000588192000025

  • Carbonate-promoted C-H carboxylation of electron-rich heteroarenes. Chemical science Porter, T. M., Kanan, M. W. 2020; 11 (43): 11936-11944


    C-H carboxylation is an attractive transformation for both streamlining synthesis and valorizing CO2. The high bond strength and very low acidity of most C-H bonds, as well as the low reactivity of CO2, present fundamental challenges for this chemistry. Conventional methods for carboxylation of electron-rich heteroarenes require very strong organic bases to effect C-H deprotonation. Here we show that alkali carbonates (M2CO3) dispersed in mesoporous TiO2 supports (M2CO3/TiO2) effect CO32--promoted C-H carboxylation of thiophene- and indole-based heteroarenes in gas-solid reactions at 200-320 °C. M2CO3/TiO2 materials are strong bases in this temperature regime, which enables deprotonation of very weakly acidic bonds in these substrates to generate reactive carbanions. In addition, we show that M2CO3/TiO2 enables C3 carboxylation of indole substrates via an apparent electrophilic aromatic substitution mechanism. No carboxylations take place when M2CO3/TiO2 is replaced with un-supported M2CO3, demonstrating the critical role of carbonate dispersion and disruption of the M2CO3 lattice. After carboxylation, treatment of the support-bound carboxylate products with dimethyl carbonate affords isolable esters and the M2CO3/TiO2 material can be regenerated upon heating under vacuum. Our results provide the basis for a closed cycle for the esterification of heteroarenes with CO2 and dimethyl carbonate.

    View details for DOI 10.1039/d0sc04548a

    View details for PubMedID 34123214

    View details for PubMedCentralID PMC8162799

  • Phase Behavior That Enables Solvent-Free Carbonate-Promoted Furoate Carboxylation. The journal of physical chemistry letters Frankhouser, A. D., Kanan, M. W. 2020: 7544–51


    Solvent-free chemistry has been used to streamline synthesis, reduce waste, and access novel reactivity, but the physical nature of the reaction medium in the absence of solvent is often poorly understood. Here we reveal the phase behavior that enables the solvent-free carboxylation reaction in which carbonate, furan-2-carboxylate (furoate), and CO2 react to form furan-2,5-dicarboxylate (FDCA2-). This transformation has no solution-phase analogue and can be applied to convert lignocellulose into performance-advantaged plastics. Using operando powder X-ray diffraction and thermal analysis to elucidate the temperature- and conversion-dependent phase composition, we find that the reaction medium is a heterogeneous mixture of a ternary eutectic molten phase, solid Cs2CO3, and solid Cs2FDCA. During the reaction, the amounts of molten phase and solid Cs2CO3 diminish as solid Cs2FDCA accumulates. These insights are critical for increasing the scale of furoate carboxylation and provide a framework for guiding the development of other solvent-free transformations.

    View details for DOI 10.1021/acs.jpclett.0c02210

    View details for PubMedID 32812764

  • Point-of-Care Analysis of Blood Ammonia with a Gas-Phase Sensor. ACS sensors Veltman, T. R., Tsai, C. J., Gomez-Ospina, N., Kanan, M. W., Chu, G. 2020


    Elevated blood ammonia (hyperammonemia) may cause delirium, brain damage, and even death. Effective treatments exist, but preventing permanent neurological sequelae requires rapid, accurate, and serial measurements of blood ammonia. Standard methods require volumes of 1 to 3 mL, centrifugation to isolate plasma, and a turn-around time of 2 h. Collection, handling, and processing requirements mean that community clinics, particularly those in low resource settings, cannot provide reliable measurements. We describe a method to measure ammonia from small-volume whole blood samples in 2 min. The method alkalizes blood to release gas-phase ammonia for detection by a fuel cell. When an inexpensive first-generation instrument designed for 100 muL of blood was tested on adults and children in a clinical study, the method showed a strong correlation (R2 = 0.97) with an academic clinical laboratory for plasma ammonia concentrations up to 500 muM (16 times higher than the upper limit of normal). A second-generation hand-held instrument designed for 10-20 muL of blood showed a near-perfect correlation (R2 = 0.99) with healthy donor blood samples containing known amounts of added ammonium chloride up to 1000 muM. Our method can enable rapid and inexpensive measurement of blood ammonia, transforming diagnosis and management of hyperammonemia.

    View details for DOI 10.1021/acssensors.0c00480

    View details for PubMedID 32538083

  • Comparing Scanning Electron Microscope and Transmission Electron Microscope Grain Mapping Techniques Applied to Well-Defined and Highly Irregular Nanoparticles. ACS omega Mariano, R. G., Yau, A., McKeown, J. T., Kumar, M., Kanan, M. W. 2020; 5 (6): 2791–99


    Investigating how grain structure affects the functional properties of nanoparticles requires a robust method for nanoscale grain mapping. In this study, we directly compare the grain mapping ability of transmission Kikuchi diffraction (TKD) in a scanning electron microscope to automated crystal orientation mapping (ACOM) in a transmission electron microscope across multiple nanoparticle materials. Analysis of well-defined Au, ZnO, and ZnSe nanoparticles showed that the grain orientations and GB geometries obtained by TKD are accurate and match those obtained by ACOM. For more complex polycrystalline Cu nanostructures, TKD provided an interpretable grain map whereas ACOM, with or without precession electron diffraction, yielded speckled, uninterpretable maps with orientation errors. Acquisition times for TKD were generally shorter than those for ACOM. Our results validate the use of TKD for characterizing grain orientation and grain boundary distributions in nanoparticles, providing a framework for the broader exploration of how microstructure influences nanoparticle properties.

    View details for DOI 10.1021/acsomega.9b03505

    View details for PubMedID 32095702

  • Polyamide monomers via carbonate-promoted C-H carboxylation of furfurylamine CHEMICAL SCIENCE Lankenau, A. W., Kanan, M. W. 2020; 11 (1): 248–52

    View details for DOI 10.1039/c9sc04460d

    View details for Web of Science ID 000503486800025

  • The future of low-temperature carbon dioxide electrolysis depends on solving one basic problem. Nature communications Rabinowitz, J. A., Kanan, M. W. 2020; 11 (1): 5231

    View details for DOI 10.1038/s41467-020-19135-8

    View details for PubMedID 33067444

  • Polyamide monomers via carbonate-promoted C-H carboxylation of furfurylamine. Chemical science Lankenau, A. W., Kanan, M. W. 2019; 11 (1): 248-252


    Inedible biomass (lignocellulose) is a largely untapped resource for polymer production because it is synthetically challenging to convert to useful monomers. Here we describe streamlined syntheses of two polyamide monomers from furfurylamine, one of very few chemicals made industrially from lignocellulose. Using carbonate-promoted C-H carboxylation, furfurylamine is converted into a furan-containing amino acid and a tetrahydrofuran-containing bicyclic lactam in two and four steps, respectively. Our syntheses avoid the use of protecting groups and multiple stoichiometric organic reagents required by previous, longer routes to these targets. This work facilitates access to furan- and tetrahydrofuran-based polyamides, which are unavailable from petrochemical feedstocks.

    View details for DOI 10.1039/c9sc04460d

    View details for PubMedID 34040718

    View details for PubMedCentralID PMC8133028

  • A closed cycle for esterifying aromatic hydrocarbons with CO2 and alcohol. Nature chemistry Xiao, D. J., Chant, E. D., Frankhouser, A. D., Chen, Y., Yau, A., Washton, N. M., Kanan, M. W. 2019


    The ability to functionalize hydrocarbons with CO2 could create opportunities for high-volume CO2 utilization. However, current methods to form carbon-carbon bonds between hydrocarbons and CO2 require stoichiometric consumption of very resource-intensive reagents to overcome the low reactivity of these substrates. Here, we report a simple semi-continuous cycle that converts aromatic hydrocarbons, CO2 and alcohol into aromatic esters without consumption of stoichiometric reagents. Our strategy centres on the use of solid bases composed of an alkali carbonate (M2CO3, where M+=K+ or Cs+) dispersed over a mesoporous support. Nanoscale confinement disrupts the crystallinity of M2CO3 and engenders strong base reactivity at intermediate temperatures. The overall cycle involves two distinct steps: (1) CO32--promoted C-H carboxylation, in which the hydrocarbon substrate is deprotonated by the supported M2CO3 and reacts with CO2 to form a supported carboxylate (RCO2M); and (2) methylation, in which RCO2M reacts with methanol and CO2 to form an isolable methyl ester with concomitant regeneration of M2CO3.

    View details for DOI 10.1038/s41557-019-0313-y

    View details for PubMedID 31451785

  • Carbon Monoxide Gas Diffusion Electrolysis that Produces Concentrated C-2 Products with High Single-Pass Conversion JOULE Ripatti, D. S., Veltman, T. R., Kanan, M. W. 2019; 3 (1): 240–56
  • Carbonate-Promoted Hydrogenation of Carbon Dioxide to Multicarbon Carboxylates. ACS central science Banerjee, A., Kanan, M. W. 2018; 4 (5): 606–13


    CO2 hydrogenation is a potential alternative to conventional petrochemical methods for making commodity chemicals and fuels. Research in this area has focused mostly on transition-metal-based catalysts. Here we show that hydrated alkali carbonates promote CO2 hydrogenation to formate, oxalate, and other C2+ carboxylates at elevated temperature and pressure in the absence of transition-metal catalysts or solvent. The reactions proceed rapidly, reaching up to 56% yield (with respect to CO32-) within minutes. Isotope labeling experiments indicate facile H2 and C-H deprotonations in the alkali cation-rich reaction media and identify probable intermediates for the C-C bond formations leading to the various C2+ products. The carboxylate salts are in equilibrium with volatile carboxylic acids under CO2 hydrogenation conditions, which may enable catalytic carboxylic acid syntheses. Our results provide a foundation for base-promoted and base-catalyzed CO2 hydrogenation processes that could complement existing approaches.

    View details for PubMedID 29806007

  • Editorial overview: Seeds for a bioenergy future CURRENT OPINION IN CHEMICAL BIOLOGY Kanan, M. W. 2017; 41: A1–A2
  • Editorial overview: Seeds for a bioenergy future. Current opinion in chemical biology Kanan, M. W. 2017; 41: A1-A2

    View details for DOI 10.1016/j.cbpa.2017.11.016

    View details for PubMedID 29223285

  • Selective increase in CO2 electroreduction activity at grain-boundary surface terminations SCIENCE Mariano, R. G., McKelvey, K., White, H. S., Kanan, M. W. 2017; 358 (6367): 1187–91


    Altering a material's catalytic properties requires identifying structural features that give rise to active surfaces. Grain boundaries create strained regions in polycrystalline materials by stabilizing dislocations and may provide a way to create high-energy surfaces for catalysis that are kinetically trapped. Although grain-boundary density has previously been correlated with catalytic activity for some reactions, direct evidence that grain boundaries create surfaces with enhanced activity is lacking. We used a combination of bulk electrochemical measurements and scanning electrochemical cell microscopy with submicrometer resolution to show that grain-boundary surface terminations in gold electrodes are more active than grain surfaces for electrochemical carbon dioxide (CO2) reduction to carbon monoxide (CO) but not for the competing hydrogen (H2) evolution reaction. The catalytic footprint of the grain boundary is commensurate with its dislocation-induced strain field, providing a strategy for broader exploitation of grain-boundary effects in heterogeneous catalysis.

    View details for PubMedID 29191908

  • Imaging the Hydrogen Absorption Dynamics of Individual Grains in Polycrystalline Palladium Thin Films in 3D. ACS nano Yau, A., Harder, R. J., Kanan, M. W., Ulvestad, A. 2017


    Defects such as dislocations and grain boundaries often control the properties of polycrystalline materials. In nanocrystalline materials, investigating this structure-function relationship while preserving the sample remains challenging because of the short length scales and buried interfaces involved. Here we use Bragg coherent diffractive imaging to investigate the role of structural inhomogeneity on the hydriding phase transformation dynamics of individual Pd grains in polycrystalline films in three-dimensional detail. In contrast to previous reports on single- and polycrystalline nanoparticles, we observe no evidence of a hydrogen-rich surface layer and consequently no size dependence in the hydriding phase transformation pressure over a 125-325 nm size range. We do observe interesting grain boundary dynamics, including reversible rotations of grain lattices while the material remains in the hydrogen-poor phase. The mobility of the grain boundaries, combined with the lack of a hydrogen-rich surface layer, suggests that the grain boundaries are acting as fast diffusion sites for the hydrogen atoms. Such hydrogen-enhanced plasticity in the hydrogen-poor phase provides insight into the switch from the size-dependent behavior of single-crystal nanoparticles to the lower transformation pressures of polycrystalline materials and may play a role in hydrogen embrittlement.

    View details for PubMedID 29035558

  • Bragg coherent diffractive imaging of single-grain defect dynamics in polycrystalline films SCIENCE Yau, A., Cha, W., Kanan, M. W., Stephenson, G. B., Ulvestad, A. 2017; 356 (6339): 739-?


    Polycrystalline material properties depend on the distribution and interactions of their crystalline grains. In particular, grain boundaries and defects are crucial in determining their response to external stimuli. A long-standing challenge is thus to observe individual grains, defects, and strain dynamics inside functional materials. Here we report a technique capable of revealing grain heterogeneity, including strain fields and individual dislocations, that can be used under operando conditions in reactive environments: grain Bragg coherent diffractive imaging (gBCDI). Using a polycrystalline gold thin film subjected to heating, we show how gBCDI resolves grain boundary and dislocation dynamics in individual grains in three-dimensional detail with 10-nanometer spatial and subangstrom displacement field resolution. These results pave the way for understanding polycrystalline material response under external stimuli and, ideally, engineering particular functions.

    View details for DOI 10.1126/science.aam6168

    View details for Web of Science ID 000401508400044

    View details for PubMedID 28522531

  • . Chemical science Beh, E. S., Basun, S. A., Feng, X., Idehenre, I. U., Evans, D. R., Kanan, M. W. 2017; 8 (4): 2790-2794


    The local environment at polarized solid-liquid interfaces provides a unique medium for chemical reactions that could be exploited to control the selectivity of non-faradaic reactions. Polarized interfaces are commonly prepared by applying a voltage to an electrode in an electrolyte solution, but it is challenging to achieve high surface charge densities while suppressing faradaic reactions. Ferroelectric materials have permanent surface charge densities that arise from the dipole moments of ferroelectric domains and can be used to create polarized solid-liquid interfaces without applying a voltage. We studied the effects of ferroelectric oxides on the selectivity of a Rh porphyrin-catalyzed carbene rearrangement. The addition of ferroelectric BaTiO3 nanoparticles to the reaction solution changed the product ratio in the same direction and by a similar magnitude as performing the reaction at an electrode-electrolyte interface polarized by a voltage. The results demonstrate that colloidal suspensions of BaTiO3 nanoparticles act as a dispersible polarized interface that can influence the selectivity of non-faradaic reactions.

    View details for DOI 10.1039/c6sc05032h

    View details for PubMedID 28553515

  • Electrostatic Control of Regioselectivity in Au(I)-Catalyzed Hydroarylation JOURNAL OF THE AMERICAN CHEMICAL SOCIETY Lau, V. M., Pfalzgraff, W. C., Markland, T. E., Kanan, M. W. 2017; 139 (11): 4035-4041


    Competing pathways in catalytic reactions often involve transition states with very different charge distributions, but this difference is rarely exploited to control selectivity. The proximity of a counterion to a charged catalyst in an ion paired complex gives rise to strong electrostatic interactions that could be used to energetically differentiate transition states. Here we investigate the effects of ion pairing on the regioselectivity of the hydroarylation of 3-substituted phenyl propargyl ethers catalyzed by cationic Au(I) complexes, which forms a mixture of 5- and 7-substituted 2H-chromenes. We show that changing the solvent dielectric to enforce ion pairing to a SbF6(-) counterion changes the regioselectivity by up to a factor of 12 depending on the substrate structure. Density functional theory (DFT) is used to calculate the energy difference between the putative product-determining isomeric transition states (ΔΔE(‡)) in both the presence and absence of the counterion. The change in ΔΔE(‡) upon switching from the unpaired transition states in high solvent dielectric to ion paired transition states in low solvent dielectric (Δ(ΔΔE(‡))) was found to be in good agreement with the experimentally observed selectivity changes across several substrates. Our calculations indicate that the origin of Δ(ΔΔE(‡)) lies in the preferential electrostatic stabilization of the transition state with greater charge separation by the counterion in the ion paired case. By performing calculations at multiple different values of the solvent dielectric, we show that the role of the solvent in changing selectivity is not solely to enforce ion pairing, but rather that interactions between the ion paired complex and the solvent also contribute to Δ(ΔΔE(‡)). Our results provide a foundation for exploiting electrostatic control of selectivity in other ion paired systems.

    View details for DOI 10.1021/jacs.6b11971

    View details for Web of Science ID 000397477700021

    View details for PubMedID 28225605

  • Molecular catalysis at polarized interfaces created by ferroelectric BaTiO3 CHEMICAL SCIENCE Beh, E. S., Basun, S. A., Feng, X., Idehenre, I. U., Evans, D. R., Kanan, M. W. 2017; 8 (4): 2790-2794

    View details for DOI 10.1039/c6sc05032h

    View details for Web of Science ID 000397560500036

  • A Direct Grain-Boundary-Activity Correlation for CO Electroreduction on Cu Nanoparticles. ACS central science Feng, X., Jiang, K., Fan, S., Kanan, M. W. 2016; 2 (3): 169-174


    Copper catalyzes the electrochemical reduction of CO to valuable C2+ products including ethanol, acetate, propanol, and ethylene. These reactions could be very useful for converting renewable energy into fuels and chemicals, but conventional Cu electrodes are energetically inefficient and have poor selectivity for CO vs H2O reduction. Efforts to design improved catalysts have been impeded by the lack of experimentally validated, quantitative structure-activity relationships. Here we show that CO reduction activity is directly correlated to the density of grain boundaries (GBs) in Cu nanoparticles (NPs). We prepared electrodes of Cu NPs on carbon nanotubes (Cu/CNT) with different average GB densities quantified by transmission electron microscopy. At potentials ranging from -0.3 V to -0.5 V vs the reversible hydrogen electrode, the specific activity for CO reduction to ethanol and acetate was linearly proportional to the fraction of NP surfaces comprised of GB surface terminations. Our results provide a design principle for CO reduction to ethanol and acetate on Cu. GB-rich Cu/CNT electrodes are the first NP catalysts with significant CO reduction activity at moderate overpotential, reaching a mass activity of up to ∼1.5 A per gram of Cu and a Faradaic efficiency >70% at -0.3 V.

    View details for DOI 10.1021/acscentsci.6b00022

    View details for PubMedID 27163043

    View details for PubMedCentralID PMC4827560

  • Carbon dioxide utilization via carbonate-promoted C-H carboxylation. Nature Banerjee, A., Dick, G. R., Yoshino, T., Kanan, M. W. 2016; 531 (7593): 215-219


    Using carbon dioxide (CO2) as a feedstock for commodity synthesis is an attractive means of reducing greenhouse gas emissions and a possible stepping-stone towards renewable synthetic fuels. A major impediment to synthesizing compounds from CO2 is the difficulty of forming carbon-carbon (C-C) bonds efficiently: although CO2 reacts readily with carbon-centred nucleophiles, generating these intermediates requires high-energy reagents (such as highly reducing metals or strong organic bases), carbon-heteroatom bonds or relatively acidic carbon-hydrogen (C-H) bonds. These requirements negate the environmental benefit of using CO2 as a substrate and limit the chemistry to low-volume targets. Here we show that intermediate-temperature (200 to 350 degrees Celsius) molten salts containing caesium or potassium cations enable carbonate ions (CO3(2-)) to deprotonate very weakly acidic C-H bonds (pKa > 40), generating carbon-centred nucleophiles that react with CO2 to form carboxylates. To illustrate a potential application, we use C-H carboxylation followed by protonation to convert 2-furoic acid into furan-2,5-dicarboxylic acid (FDCA)--a highly desirable bio-based feedstock with numerous applications, including the synthesis of polyethylene furandicarboxylate (PEF), which is a potential large-scale substitute for petroleum-derived polyethylene terephthalate (PET). Since 2-furoic acid can readily be made from lignocellulose, CO3(2-)-promoted C-H carboxylation thus reveals a way to transform inedible biomass and CO2 into a valuable feedstock chemical. Our results provide a new strategy for using CO2 in the synthesis of multi-carbon compounds.

    View details for DOI 10.1038/nature17185

    View details for PubMedID 26961655

  • Probing the Active Surface Sites for CO Reduction on Oxide-Derived Copper Electrocatalysts JOURNAL OF THE AMERICAN CHEMICAL SOCIETY Verdaguer-Casadevall, A., Li, C. W., Johansson, T. P., Scott, S. B., McKeown, J. T., Kumar, M., Stephens, I. E., Kanan, M. W., Chorkendorff, I. 2015; 137 (31): 9808-9811


    CO electroreduction activity on oxide-derived Cu (OD-Cu) was found to correlate with metastable surface features that bind CO strongly. OD-Cu electrodes prepared by H2 reduction of Cu2O precursors reduce CO to acetate and ethanol with nearly 50% Faradaic efficiency at moderate overpotential. Temperature-programmed desorption of CO on OD-Cu revealed the presence of surface sites with strong CO binding that are distinct from the terraces and stepped sites found on polycrystalline Cu foil. After annealing at 350 °C, the surface-area corrected current density for CO reduction is 44-fold lower and the Faradaic efficiency is less than 5%. These changes are accompanied by a reduction in the proportion of strong CO binding sites. We propose that the active sites for CO reduction on OD-Cu surfaces are strong CO binding sites that are supported by grain boundaries. Uncovering these sites is a first step toward understanding the surface chemistry necessary for efficient CO electroreduction.

    View details for DOI 10.1021/jacs.5b06227

    View details for Web of Science ID 000359613300013

    View details for PubMedID 26196863

  • Correction: Electrostatic control of regioselectivity via ion pairing in a Au(i)-catalyzed rearrangement. Chemical science Lau, V. M., Gorin, C. F., Kanan, M. W. 2015; 6 (5): 3268


    [This corrects the article DOI: 10.1039/C4SC02058H.].

    View details for DOI 10.1039/c5sc90018b

    View details for PubMedID 30124683

    View details for PubMedCentralID PMC6063290

  • Pd-catalyzed electrohydrogenation of carbon dioxide to formate: high mass activity at low overpotential and identification of the deactivation pathway. Journal of the American Chemical Society Min, X., Kanan, M. W. 2015; 137 (14): 4701-4708


    Electrochemical reduction of CO2 to formate (HCO2(-)) powered by renewable electricity is a possible carbon-negative alternative to synthesizing formate from fossil fuels. This process is energetically inefficient because >1 V of overpotential is required for CO2 reduction to HCO2(-) on the metals currently used as cathodic catalysts. Pd reduces CO2 to HCO2(-) with no overpotential, but this activity has previously been limited to low synthesis rates and plagued by an unidentified deactivation pathway. Here we show that Pd nanoparticles dispersed on a carbon support reach high mass activities (50-80 mA HCO2(-) synthesis per mg Pd) when driven by less than 200 mV of overpotential in aqueous bicarbonate solutions. Electrokinetic measurements are consistent with a mechanism in which the rate-determining step is the addition of electrochemically generated surface adsorbed hydrogen to CO2 (i.e., electrohydrogenation). The electrodes deactivate over the course of several hours because of a minor pathway that forms CO. Activity is recovered, however, by removing CO with brief air exposure.

    View details for DOI 10.1021/ja511890h

    View details for PubMedID 25812119

  • Grain-Boundary-Dependent CO2 Electroreduction Activity. Journal of the American Chemical Society Feng, X., Jiang, K., Fan, S., Kanan, M. W. 2015; 137 (14): 4606-4609


    Uncovering new structure-activity relationships for metal nanoparticle (NP) electrocatalysts is crucial for advancing many energy conversion technologies. Grain boundaries (GBs) could be used to stabilize unique active surfaces, but a quantitative correlation between GBs and catalytic activity has not been established. Here we use vapor deposition to prepare Au NPs on carbon nanotubes (Au/CNT). As deposited, the Au NPs have a relatively high density of GBs that are readily imaged by transmission electron microscopy (TEM); thermal annealing lowers the density in a controlled manner. We show that the surface-area-normalized activity for CO2 reduction is linearly correlated with GB surface density on Au/CNT, demonstrating that GB engineering is a powerful approach to improving the catalytic activity of metal NPs.

    View details for DOI 10.1021/ja5130513

    View details for PubMedID 25835085

  • Controlling H+ vs CO2 Reduction Selectivity on Pb Electrodes ACS CATALYSIS Lee, C. H., Kanan, M. W. 2015; 5 (1): 465-469

    View details for DOI 10.1021/cs5017672

    View details for Web of Science ID 000347513400057

  • Alkaline O2 reduction on oxide-derived Au: high activity and 4e¯ selectivity without (100) facets. Physical chemistry chemical physics Min, X., Chen, Y., Kanan, M. W. 2014; 16 (27): 13601-13604


    Gold films produced from gold oxide precursors ("oxide-derived Au") were compared to polyhedral Au nanoparticles for electrocatalytic alkaline O2 reduction. Despite having no detectable abundance of (100) facets, oxide-derived Au exhibited 4e(-) selectivity and surface-area-normalized activity that rivaled cubic Au nanoparticles with high (100) abundance. The activity of oxide-derived Au likely arises from active sites at the surface terminations of defects that are trapped during gold oxide reduction.

    View details for DOI 10.1039/c4cp01337a

    View details for PubMedID 24849198

  • Electroreduction of carbon monoxide to liquid fuel on oxide-derived nanocrystalline copper NATURE Li, C. W., Ciston, J., Kanan, M. W. 2014; 508 (7497): 504-?


    The electrochemical conversion of CO2 and H2O into liquid fuel is ideal for high-density renewable energy storage and could provide an incentive for CO2 capture. However, efficient electrocatalysts for reducing CO2 and its derivatives into a desirable fuel are not available at present. Although many catalysts can reduce CO2 to carbon monoxide (CO), liquid fuel synthesis requires that CO is reduced further, using H2O as a H(+) source. Copper (Cu) is the only known material with an appreciable CO electroreduction activity, but in bulk form its efficiency and selectivity for liquid fuel are far too low for practical use. In particular, H2O reduction to H2 outcompetes CO reduction on Cu electrodes unless extreme overpotentials are applied, at which point gaseous hydrocarbons are the major CO reduction products. Here we show that nanocrystalline Cu prepared from Cu2O ('oxide-derived Cu') produces multi-carbon oxygenates (ethanol, acetate and n-propanol) with up to 57% Faraday efficiency at modest potentials (-0.25 volts to -0.5 volts versus the reversible hydrogen electrode) in CO-saturated alkaline H2O. By comparison, when prepared by traditional vapour condensation, Cu nanoparticles with an average crystallite size similar to that of oxide-derived copper produce nearly exclusive H2 (96% Faraday efficiency) under identical conditions. Our results demonstrate the ability to change the intrinsic catalytic properties of Cu for this notoriously difficult reaction by growing interconnected nanocrystallites from the constrained environment of an oxide lattice. The selectivity for oxygenates, with ethanol as the major product, demonstrates the feasibility of a two-step conversion of CO2 to liquid fuel that could be powered by renewable electricity.

    View details for DOI 10.1038/nature13249

    View details for Web of Science ID 000334741600032

    View details for PubMedID 24717429

  • Alkaline O-2 reduction on oxide-derived Au: high activity and 4e(-) selectivity without (100) facets PHYSICAL CHEMISTRY CHEMICAL PHYSICS Min, X., Chen, Y., Kanan, M. W. 2014; 16 (27): 13601-13604

    View details for DOI 10.1039/c4cp01337a

    View details for Web of Science ID 000338116700005

  • Electrostatic control of regioselectivity via ion pairing in a Au(I)-catalyzed rearrangement CHEMICAL SCIENCE Lau, V. M., Gorin, C. F., Kanan, M. W. 2014; 5 (12): 4975-4979

    View details for DOI 10.1039/c4sc02058h

    View details for Web of Science ID 000344376400055

  • Interfacial electric field effects on a carbene reaction catalyzed by rh porphyrins. Journal of the American Chemical Society Gorin, C. F., Beh, E. S., Bui, Q. M., Dick, G. R., Kanan, M. W. 2013; 135 (30): 11257-11265


    An intramolecular reaction catalyzed by Rh porphyrins was studied in the presence of interfacial electric fields. 1-Diazo-3,3-dimethyl-5-phenylhex-5-en-2-one (2) reacts with Rh porphyrins via a putative carbenoid intermediate to form cyclopropanation product 3,3-dimethyl-5-phenylbicyclo[3.1.0]hexan-2-one (3) and insertion product 3,3-dimethyl-2,3-dihydro-[1,1'-biphenyl]-4(1H)-one (4). To study this reaction in the presence of an interfacial electric field, Si electrodes coated with thin films of insulating dielectric layers were used as the opposing walls of a reaction vessel, and Rh porphyrin catalysts were localized to the dielectric-electrolyte interface. The charge density was varied at the interface by changing the voltage across the two electrodes. The product ratio was analyzed as a function of the applied voltage and the surface chemistry of the dielectric layer. In the absence of an applied voltage, the ratio of 3:4 was approximately 10:1. With a TiO2 surface, application of a voltage induced a Rh porphyrin-TiO2 interaction that resulted in an increase in the 3:4 ratio to a maximum in which 4 was nearly completely suppressed (>100:1). With an Al2O3 surface or an alkylphosphonate-coated surface, the voltage caused a decrease in the 3:4 ratio, with a maximum effect of lowering the ratio to 1:2. The voltage-induced decrease in the 3:4 ratio in the absence of TiO2 was consistent with a field-dipole effect that changed the difference in activation energies for the product-determining step to favor product 4. Effects were observed for porphyrin catalysts localized to the electrode-electrolyte interface either through covalent attachment or surface adsorption, enabling the selectivity to be controlled with unfunctionalized Rh porphyrins. The magnitude of the selectivity change was limited by the maximum interfacial charge density that could be attained before dielectric breakdown.

    View details for DOI 10.1021/ja404394z

    View details for PubMedID 23837635

  • Aqueous CO2 Reduction at Very Low Overpotential on Oxide-Derived Au Nanoparticles JOURNAL OF THE AMERICAN CHEMICAL SOCIETY Chen, Y., Li, C. W., Kanan, M. W. 2012; 134 (49): 19969-19972


    Carbon dioxide reduction is an essential component of many prospective technologies for the renewable synthesis of carbon-containing fuels. Known catalysts for this reaction generally suffer from low energetic efficiency, poor product selectivity, and rapid deactivation. We show that the reduction of thick Au oxide films results in the formation of Au nanoparticles ("oxide-derived Au") that exhibit highly selective CO(2) reduction to CO in water at overpotentials as low as 140 mV and retain their activity for at least 8 h. Under identical conditions, polycrystalline Au electrodes and several other nanostructured Au electrodes prepared via alternative methods require at least 200 mV of additional overpotential to attain comparable CO(2) reduction activity and rapidly lose their activity. Electrokinetic studies indicate that the improved catalysis is linked to dramatically increased stabilization of the CO(2)(•-) intermediate on the surfaces of the oxide-derived Au electrodes.

    View details for DOI 10.1021/ja309317u

    View details for Web of Science ID 000312351000005

    View details for PubMedID 23171134

  • CO2 Reduction at Low Overpotential on Cu Electrodes Resulting from the Reduction of Thick Cu2O Films JOURNAL OF THE AMERICAN CHEMICAL SOCIETY Li, C. W., Kanan, M. W. 2012; 134 (17): 7231-7234


    Modified Cu electrodes were prepared by annealing Cu foil in air and electrochemically reducing the resulting Cu(2)O layers. The CO(2) reduction activities of these electrodes exhibited a strong dependence on the initial thickness of the Cu(2)O layer. Thin Cu(2)O layers formed by annealing at 130 °C resulted in electrodes whose activities were indistinguishable from those of polycrystalline Cu. In contrast, Cu(2)O layers formed at 500 °C that were ≥~3 μm thick resulted in electrodes that exhibited large roughness factors and required 0.5 V less overpotential than polycrystalline Cu to reduce CO(2) at a higher rate than H(2)O. The combination of these features resulted in CO(2) reduction geometric current densities >1 mA/cm(2) at overpotentials <0.4 V, a higher level of activity than all previously reported metal electrodes evaluated under comparable conditions. Moreover, the activity of the modified electrodes was stable over the course of several hours, whereas a polycrystalline Cu electrode exhibited deactivation within 1 h under identical conditions. The electrodes described here may be particularly useful for elucidating the structural properties of Cu that determine the distribution between CO(2) and H(2)O reduction and provide a promising lead for the development of practical catalysts for electrolytic fuel synthesis.

    View details for DOI 10.1021/ja3010978

    View details for Web of Science ID 000303362900010

    View details for PubMedID 22506621

  • Tin Oxide Dependence of the CO2 Reduction Efficiency on Tin Electrodes and Enhanced Activity for Tin/Tin Oxide Thin-Film Catalysts JOURNAL OF THE AMERICAN CHEMICAL SOCIETY Chen, Y., Kanan, M. W. 2012; 134 (4): 1986-1989


    The importance of tin oxide (SnO(x)) to the efficiency of CO(2) reduction on Sn was evaluated by comparing the activity of Sn electrodes that had been subjected to different pre-electrolysis treatments. In aqueous NaHCO(3) solution saturated with CO(2), a Sn electrode with a native SnO(x) layer exhibited potential-dependent CO(2) reduction activity consistent with previously reported activity. In contrast, an electrode etched to expose fresh Sn(0) surface exhibited higher overall current densities but almost exclusive H(2) evolution over the entire 0.5 V range of potentials examined. Subsequently, a thin-film catalyst was prepared by simultaneous electrodeposition of Sn(0) and SnO(x) on a Ti electrode. This catalyst exhibited up to 8-fold higher partial current density and 4-fold higher faradaic efficiency for CO(2) reduction than a Sn electrode with a native SnO(x) layer. Our results implicate the participation of SnO(x) in the CO(2) reduction pathway on Sn electrodes and suggest that metal/metal oxide composite materials are promising catalysts for sustainable fuel synthesis.

    View details for DOI 10.1021/ja2108799

    View details for Web of Science ID 000301084600024

    View details for PubMedID 22239243

  • An Electric Field-Induced Change in the Selectivity of a Metal Oxide-Catalyzed Epoxide Rearrangement JOURNAL OF THE AMERICAN CHEMICAL SOCIETY Gorin, C. F., Beh, E. S., Kanan, M. W. 2012; 134 (1): 186-189


    The rearrangement of cis-stilbene oxide catalyzed by Al(2)O(3) was studied in the presence of interfacial electric fields. Thin films of Al(2)O(3) deposited on Si electrodes were used as the opposing walls of a reaction vessel. Application of a voltage across the electrodes engendered electrochemical double layer formation at the Al(2)O(3)-solution interface. The aldehyde to ketone product ratio of the rearrangement was increased by up to a factor of 63 as the magnitude of the double layer charge density was increased. The results support a field-dipole effect on the selectivity of the catalytic reaction.

    View details for DOI 10.1021/ja210365j

    View details for Web of Science ID 000301084200049

    View details for PubMedID 22191979