Tailoring Reaction Pathways by Tuning the Surface Composition of AuPt Nanocatalysts for Enhanced Formic Acid Oxidation
Xiang Li, Junjun Zhang, Changqing Jin, Bo Yan, Jiyun Cai, Mengyang Li, Xinyuan Peng, Yixuan Wang
Abstract
Pt-based nanocatalysts are universally applied in direct formic acid fuel cells. For Pt-based nanocatalysts, formic acid oxidation involves two pathways: dehydrogenation and dehydration. Dehydration, due to the production of CO, can poison the surface of the catalyst and thus reduce the catalytic efficiency. The tuning of the composition of Pt-based nanocrystals can effectively improve selectivity for dehydrogenation, especially for AuPt nanocrystals. However, it is still a challenge to tune the composition of AuPt nanocrystals in a nanometer size. Herein, we put forward a remarkably effortless technique for tailoring reaction pathways of formic acid oxidation by tuning the surface composition of AuPt nanocatalysts. Compared with the unmodified AuPt nanoparticles and commercial Pt/C nanocatalysts, the modified AuPt nanoparticles exhibit significantly enhanced catalytic properties. It shows a mass activity of 1.94 mA mgPt–1 at 0.61 V versus the reversible hydrogen electrode, 19.4 times and 7.5 times higher than that of Pt/C nanocatalysts (0.1 mA mgPt–1) and Pt-rich Au@Pt nanoparticles (0.26 mA mgPt–1), respectively. Meanwhile, it also exhibits that the specific activity of modified AuPt nanoparticles is 7.89 mA cm–2 at 0.61 V, 46.4 times and 7.2 times higher than that of the Pt/C reference (0.17 mA cm–2) and Pt-rich Au@Pt nanoparticles (1.09 mA cm–2), respectively.