Education & Certifications
Bachelor of Engineering, Tsinghua University, Materials Science and Engineering (2018)
Templated encapsulation of platinum-based catalysts promotes high-temperature stability to 1,100°C.
Stable catalysts are essential to address energy and environmental challenges, especially for applications in harsh environments (for example, high temperature, oxidizing atmosphere and steam). In such conditions, supported metal catalysts deactivate due to sintering-a process where initially small nanoparticles grow into larger ones with reduced active surface area-but strategies to stabilize them can lead to decreased performance. Here we report stable catalysts prepared through the encapsulation of platinum nanoparticles inside an alumina framework, which was formed by depositing an alumina precursor within a separately prepared porous organic framework impregnated with platinum nanoparticles. These catalysts do not sinter at 800°C in the presence of oxygen and steam, conditions in which conventional catalysts sinter to a large extent, while showing similar reaction rates. Extending this approach to Pd-Pt bimetallic catalysts led to the small particle size being maintained at temperatures as high as 1,100°C in air and 10% steam. This strategy can be broadly applied to other metal and metal oxides for applications where sintering is a major cause of material deactivation.
View details for DOI 10.1038/s41563-022-01376-1
View details for PubMedID 36280703
- Understanding the geometric and basicity effects of organic polymer modifiers on Ru/TiO2 catalysts for CO2 hydrogenation to hydrocarbons CATALYSIS SCIENCE & TECHNOLOGY 2022
- Surface Fe clusters promote syngas reaction to oxygenates on Rh catalysts modified by atomic layer deposition JOURNAL OF CATALYSIS 2022; 414: 125-136
- Strategies for Modulating the Catalytic Activity and Selectivity of Manganese Antimonates for the Oxygen Reduction Reaction ACS CATALYSIS 2022
Recycling of Solvent Allows for Multiple Rounds of Reproducible Nanoparticle Synthesis.
Journal of the American Chemical Society
Metal nanoparticles have superior properties for a variety of applications. In many cases, the improved performance of metal nanoparticles is tightly correlated with their size and atomic composition. To date, colloidal synthesis is the most commonly used technique to produce metal nanoparticles. However, colloidal synthesis is currently a laboratory scale technique that has not been applied at larger scales. One of the greatest challenges facing large-scale colloidal synthesis of metal nanoparticles is the large volume of long-chain hydrocarbon solvents and surfactants needed for the synthesis, which can dominate the cost of nanoparticle production. In this work, we demonstrate a protocol, based on solvent distillation, which enables the reuse of colloidal nanoparticle synthesis surfactants and solvents for over 10 rounds of successive syntheses and demonstrates that pure solvents and surfactants are not necessarily needed to produce uniform nanocrystals. We show that this protocol can be applied to the production of a wide variety of mono- and bimetallic nanoparticles with reproducible sizes and compositions, which leads to reproducible performance as heterogeneous catalysts. A techno-economic assessment demonstrates the potential of this technique to greatly reduce the solvent-related costs of colloidal metal nanoparticle synthesis, which could contribute to its wider application at commercial scale.
View details for DOI 10.1021/jacs.2c02837
View details for PubMedID 35737471
Steering CO2 hydrogenation toward C-C coupling to hydrocarbons using porous organic polymer/metal interfaces.
Proceedings of the National Academy of Sciences of the United States of America
2022; 119 (7)
The conversion of CO2 into fuels and chemicals is an attractive option for mitigating CO2 emissions. Controlling the selectivity of this process is beneficial to produce desirable liquid fuels, but C-C coupling is a limiting step in the reaction that requires high pressures. Here, we propose a strategy to favor C-C coupling on a supported Ru/TiO2 catalyst by encapsulating it within the polymer layers of an imine-based porous organic polymer that controls its selectivity. Such polymer confinement modifies the CO2 hydrogenation behavior of the Ru surface, significantly enhancing the C2+ production turnover frequency by 10-fold. We demonstrate that the polymer layers affect the adsorption of reactants and intermediates while being stable under the demanding reaction conditions. Our findings highlight the promising opportunity of using polymer/metal interfaces for the rational engineering of active sites and as a general tool for controlling selective transformations in supported catalyst systems.
View details for DOI 10.1073/pnas.2114768119
View details for PubMedID 35135880
Voltage cycling process for the electroconversion of biomass-derived polyols.
Proceedings of the National Academy of Sciences of the United States of America
2021; 118 (41)
Electrification of chemical reactions is crucial to fundamentally transform our society that is still heavily dependent on fossil resources and unsustainable practices. In addition, electrochemistry-based approaches offer a unique way of catalyzing reactions by the fast and continuous alteration of applied potentials, unlike traditional thermal processes. Here, we show how the continuous cyclic application of electrode potential allows Pt nanoparticles to electrooxidize biomass-derived polyols with turnover frequency improved by orders of magnitude compared with the usual rates at fixed potential conditions. Moreover, secondary alcohol oxidation is enhanced, with a ketoses-to-aldoses ratio increased up to sixfold. The idea has been translated into the construction of a symmetric single-compartment system in a two-electrode configuration. Its operation via voltage cycling demonstrates high-rate sorbitol electrolysis with the formation of H2 as a desired coproduct at operating voltages below 1.4 V. The devised method presents a potential approach to using renewable electricity to drive chemical processes.
View details for DOI 10.1073/pnas.2113382118
View details for PubMedID 34615713
A General Approach for Monolayer Adsorption of High Weight Loadings of Uniform Nanocrystals on Oxide Supports.
Angewandte Chemie (International ed. in English)
Monodispersed metal and semiconductor nanocrystals have attracted great attention in fundamental and applied research due to their tunable size, morphology, and well-defined chemical composition. Utilizing these nanocrystals in a controllable way is highly desirable especially when using them as building blocks for the preparation of nanostructured materials. Their deposition onto oxide materials provide them with wide applicability in many areas, including catalysis. However, so far deposition methods are limited and do not provide control to achieve high particle loadings. This study demonstrates a general approach for the deposition of hydrophobic ligand-stabilized nanocrystals on hydrophilic oxide supports without ligand-exchange. Surface functionalization of the supports with primary amine groups either using an organosilane ((3-aminopropyl)trimethoxysilane) or bonding with aminoalcohols (3-amino-1,2-propanediol) were found to significantly improve the interaction between nanocrystals and supports achieving high loadings (>10 wt. %). The bonding method with aminoalcohols guarantees the opportunity to remove the binding molecules thus allowing clean metal/oxide materials to be obtained, which is of great importance in the preparation of supported nanocrystals for heterogeneous catalysis.
View details for DOI 10.1002/anie.202017238
View details for PubMedID 33403788
- Steam-created grain boundaries for methane C-H activation in palladium catalysts. Science (New York, N.Y.) 2021; 373 (6562): 1518-1523
Design of Organic/Inorganic Hybrid Catalysts for Energy and Environmental Applications.
ACS central science
2020; 6 (11): 1916–37
Controlling selectivity between competing reaction pathways is crucial in catalysis. Several approaches have been proposed to achieve this goal in traditional heterogeneous catalysts including tuning nanoparticle size, varying alloy composition, and controlling supporting material. A less explored and promising research area to control reaction selectivity is via the use of hybrid organic/inorganic catalysts. These materials contain inorganic components which serve as sites for chemical reactions and organic components which either provide diffusional control or directly participate in the formation of active site motifs. Despite the appealing potential of these hybrid materials to increase reaction selectivity, there are significant challenges to the rational design of such hybrid nanostructures. Structural and mechanistic characterization of these materials play a key role in understanding and, therefore, designing these organic/inorganic hybrid catalysts. This Outlook highlights the design of hybrid organic/inorganic catalysts with a brief overview of four different classes of materials and discusses the practical catalytic properties and opportunities emerging from such designs in the area of energy and environmental transformations. Key structural and mechanistic characterization studies are identified to provide fundamental insight into the atomic structure and catalytic behavior of hybrid organic/inorganic catalysts. Exemplary works are used to show how specific active site motifs allow for remarkable changes in the reaction selectivity. Finally, to demonstrate the potential of hybrid catalyst materials, we suggest a characterization-based approach toward the design of biomimetic hybrid organic/inorganic materials for a specific application in the energy and environmental research space: the conversion of methane into methanol.
View details for DOI 10.1021/acscentsci.0c01046
View details for PubMedID 33274270
View details for PubMedCentralID PMC7706093
- High Areal Capacity Li-Ion Storage of Binder-Free Metal Vanadate/Carbon Hybrid Anode by Ion-Exchange Reaction SMALL 2018; 14 (35)
High Areal Capacity Li-Ion Storage of Binder-Free Metal Vanadate/Carbon Hybrid Anode by Ion-Exchange Reaction.
Small (Weinheim an der Bergstrasse, Germany)
Storing more energy in a limited device area is very challenging but crucial for the applications of flexible and wearable electronics. Metal vanadates have been regarded as a fascinating group of materials in many areas, especially in lithium-ion storage. However, there has not been a versatile strategy to synthesize flexible metal vanadate hybrid nanostructures as binder-free anodes for Li-ion batteries so far. A convenient and versatile synthesis of Mx Vy Ox+2.5y @carbon cloth (M = Mn, Co, Ni, Cu) composites is proposed here based on a two-step hydrothermal route. As-synthesized products demonstrate hierarchical proliferous structure, ranging from nanoparticles (0D), and nanobelts (1D) to a 3D interconnected network. The metal vanadate/carbon hybrid nanostructures exhibit excellent lithium storage capability, with a high areal specific capacity up to 5.9 mAh cm-2 (which equals to 1676.8 mAh g-1 ) at a current density of 200 mA g-1 . Moreover, the nature of good flexibility, mixed valence states, and ultrahigh mass loading density (over 3.5 mg cm-2 ) all guarantee their great potential in compact energy storage for future wearable devices and other related applications.
View details for PubMedID 30066386
- High areal specific capacity of Ni3V2O8/carbon cloth hierarchical structures as flexible anodes for sodium-ion batteries JOURNAL OF MATERIALS CHEMISTRY A 2017; 5 (30): 15517–24