Doctor of Philosophy, Stanford University, EE-PMN (2016)
Doctor of Philosophy, Stanford University, ME-PHD (2016)
Master of Science, Stanford University, CEE-MS (2011)
Bachelor of Engineering, Tsinghua University, Environmental Engineering (2009)
Direct and continuous strain control of catalysts with tunable battery electrode materials
2016; 354 (6315): 1031-1036
We report a method for using battery electrode materials to directly and continuously control the lattice strain of platinum (Pt) catalyst and thus tune its catalytic activity for the oxygen reduction reaction (ORR). Whereas the common approach of using metal overlayers introduces ligand effects in addition to strain, by electrochemically switching between the charging and discharging status of battery electrodes the change in volume can be precisely controlled to induce either compressive or tensile strain on supported catalysts. Lattice compression and tension induced by the lithium cobalt oxide substrate of ~5% were directly observed in individual Pt nanoparticles with aberration-corrected transmission electron microscopy. We observed 90% enhancement or 40% suppression in Pt ORR activity under compression or tension, respectively, which is consistent with theoretical predictions.
View details for DOI 10.1126/science.aaf7680
View details for Web of Science ID 000388531800044
View details for PubMedID 27885028
- Atomically Flat Silicon Oxide Monolayer Generated by Remote Plasma JOURNAL OF PHYSICAL CHEMISTRY C 2016; 120 (15): 8148-8156
- Oscillatory barrier-assisted Langmuir-Blodgett deposition of large-scale quantum dot monolayers APPLIED SURFACE SCIENCE 2016; 367: 500-506
- Self-limiting atomic layer deposition of barium oxide and barium titanate thin films using a novel pyrrole based precursor JOURNAL OF MATERIALS CHEMISTRY C 2016; 4 (10): 1945-1952
- Quantifying Geometric Strain at the PbS QD-TiO2 Anode Interface and Its Effect on Electronic Structures NANO LETTERS 2015; 15 (12): 7829-7836
Variation of Energy Density of States in Quantum Dot Arrays due to Interparticle Electronic Coupling.
2015; 15 (3): 1855-1860
Subnanometer-resolved local electron energy structure was measured in PbS quantum dot superlattice arrays using valence electron energy loss spectroscopy with scanning transmission electron microscopy. We found smaller values of the lowest available transition energies and an increased density of electronic states in the space between quantum dots with shorter interparticle spacing, indicating extension of carrier wave functions as a result of interparticle electronic coupling. A quantum simulation verified both trends and illustrated the wave function extension effect.
View details for DOI 10.1021/nl5046507
View details for PubMedID 25670055
- Effects of size polydispersity on electron mobility in a two-dimensional quantum-dot superlattice PHYSICAL REVIEW B 2014; 90 (14)
Electrochemical tuning of vertically aligned MoS2 nanofilms and its application in improving hydrogen evolution reaction
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
2013; 110 (49): 19701-19706
The ability to intercalate guest species into the van der Waals gap of 2D layered materials affords the opportunity to engineer the electronic structures for a variety of applications. Here we demonstrate the continuous tuning of layer vertically aligned MoS2 nanofilms through electrochemical intercalation of Li(+) ions. By scanning the Li intercalation potential from high to low, we have gained control of multiple important material properties in a continuous manner, including tuning the oxidation state of Mo, the transition of semiconducting 2H to metallic 1T phase, and expanding the van der Waals gap until exfoliation. Using such nanofilms after different degree of Li intercalation, we show the significant improvement of the hydrogen evolution reaction activity. A strong correlation between such tunable material properties and hydrogen evolution reaction activity is established. This work provides an intriguing and effective approach on tuning electronic structures for optimizing the catalytic activity.
View details for DOI 10.1073/pnas.1316792110
View details for Web of Science ID 000327744900025
View details for PubMedID 24248362
- Efficiency enhancement of solid-state PbS quantum dot-sensitized solar cells with Al2O3 barrier layer JOURNAL OF MATERIALS CHEMISTRY A 2013; 1 (26): 7566-7571
Effects of QD Surface Coverage in Solid-State PbS Quantum Dot-Sensitized Solar Cells
39th IEEE Photovoltaic Specialists Conference (PVSC)
IEEE. 2013: 1080–1083
View details for Web of Science ID 000340054100239
- Nickel Silicide Nanowire Arrays for Anti-Reflective Electrodes in Photovoltaics ADVANCED FUNCTIONAL MATERIALS 2012; 22 (17): 3650-3657