| AVS 62nd International Symposium & Exhibition | |
| Nanometer-scale Science and Technology | Wednesday Sessions |
| Session NS+EN+MG+SS+TF-WeA |
| Session: | Nanoscale Catalysis and Surface Chemistry |
| Presenter: | Xiaofeng Feng, Stanford University |
| Authors: | X. Feng, Stanford University M. Kanan, Stanford University |
| Correspondent: | Click to Email |
New design principles for electroreduction catalysts are essential for CO2 recycling using renewable electricity. Au is one of the most active catalysts for CO2 reduction to CO, and numerous efforts have been made to optimize Au catalysts by tuning the size, composition, and shape of Au nanostructures. Here we show that grain boundaries (GBs) in Au nanoparticles create highly active surface sites for CO2 electroreduction (1). Defect-rich Au nanoparticles were synthesized by vapor deposition of Au onto a carbon nanotube thin film, which enables direct TEM characterization without further processing. We compared the CO2 reduction activity of the as-deposited catalysts to those annealed at different temperatures. While the annealing process has little impact on the distribution of Au surface facets, it reduces the GB density, which is quantified by measuring GB lengths and particle areas from high-resolution TEM images. We found that the surface-area-normalized activity for CO2 reduction is linearly correlated with GB density in Au nanoparticles in the low overpotential regime. Similarly, GB-density was also found to correlate with catalytic activity for the electroreduction of CO to multi-carbon oxygenates on Cu nanoparticles. Our studies show that grain boundary engineering is a general strategy for improving electrocatalytic activity for carbon fuel synthesis.
References:
(1) Feng, X.; Jiang, K.; Fan, S.; Kanan, M. W. J. Am. Chem. Soc.2015, 137, 4606–4609.