| AVS 64th International Symposium & Exhibition | |
| Fundamental Discoveries in Heterogeneous Catalysis Focus Topic | Wednesday Sessions |
| Session HC+NS+SS-WeM |
| Session: | Nanoscale Surface Structures in Heterogeneously-Catalyzed Reactions |
| Presenter: | Xiaofeng Feng, University of Central Florida |
| Correspondent: | Click to Email |
Identification of active sites on a catalyst surface is the key to a rational design of heterogeneous catalysts. For nanoparticle catalysts, most efforts to tailor their surfaces have focused on controlling particle size, shape, and composition. The atomic surface sites underlying these structural features are mainly facets, steps, edges, and corner sites. These efforts have led to important progresses in heterogeneous catalysis, but it is unclear if the accessible structure space is sufficient for finding optimal catalysts. One alternative is to use bulk defects such as grain boundaries (GBs) to stabilize catalytically active surfaces. Here we show that the GBs in metal nanoparticles create new active sites for electrochemical catalysis. Through a careful design of metal nanoparticle catalysts with different GB densities, extensive TEM characterization, and electrochemical measurements, we discovered that the catalytic activity for CO2 reduction on Au and CO reduction on Cu is linearly correlated with the GB density in the catalysts [1, 2]. The quantitative GB-activity relationship implicates GB surface terminations as new active sites and lead to highly active and stable electrocatalysts for a two-step conversion of CO2 to liquid fuels such as ethanol and acetate. In addition, we found that the GBs in Au enhance its activity for oxygen reduction reaction, suggesting that GB engineering may be a general strategy to improve heterogeneous catalysis for renewable energy conversion.
References:
(1) Feng, X.; Jiang, K.; Fan, S.; Kanan, M. W. J. Am. Chem. Soc.2015, 137, 4606–4609.
(2) Feng, X.; Jiang, K.; Fan, S.; Kanan, M. W. ACS Cent. Sci.2016, 2, 169−174.