Dual-Site Cascade Oxygen Reduction Mechanism on SnO x /Pt–Cu–Ni for Promoting Reaction Kinetics

作者：Xiaochen Shen, Tomoyuki NAGAI, Feipeng Yang, Li Qin Zhou, Yanbo Pan, Libo Yao, Dezhen Wu, Yi‐Sheng Liu, Jun Feng, Jinghua Guo, Hongfei Jia, Zhenmeng Peng · 发表于：Journal of the American Chemical Society · 年份：2019 · DOI：10.1021/jacs.9b02286 · 被引用次数：99 · 研究领域：Electrocatalysts for Energy Conversion、Fuel Cells and Related Materials、Advanced battery technologies research

Designing highly active oxygen reduction reaction (ORR) catalysts is crucial to boost the fuel cell economy. Previous research has mainly focused on Pt-based alloy catalysts in which surface Pt is the solely active site and the activity improvement was challenged by the discovered scaling relationship. Herein we report a new concept of utilizing dual active sites for the ORR and demonstrate its effectiveness by synthesizing a SnO x /Pt–Cu–Ni heterojunctioned catalyst. A maximum of 40% enhancement in the apparent specific activity, which corresponds to 10-fold enhancement on interface sites, is measured compared with pure Pt–Cu–Ni. Detailed investigations suggest an altered dual-site cascade mechanism wherein the first two steps occur on SnO x sites and the remaining steps occur on adjacent Pt sites, allowing a significant decrease in the energy barrier. This study with the suggested dual-site cascade mechanism shows the potential to overcome the ORR energy barrier bottleneck to develop highly active catalysts.