Boosting Electrocatalytic Hydrazine Oxidation Reaction on High-Index Faceted Au Concave Trioctahedral Nanocrystals

High-index faceted Au nanocrystals are explored as an efficient catalyst in the electrocatalytic hydrazine oxidation reaction (HzOR). Theoretical calculations reveal that the Au(551) surface is more active than the Au(111) surface toward HzOR with lower overpotentials, and the step atoms on the Au(551) surface serve as high-active sites to enhance HzOR. Experimentally, the as-prepared concave trioctahedral Au nanocrystals (TOH Au NCs) enclosed by {551} high-index facets (HIFs) exhibit excellent electrocatalytic performance of HzOR under both alkaline and acidic conditions. Particularly, the concave TOH Au NCs achieve very high activities of 272.3 mA cm–2 (mass activity, 1472.6 mA mg–1) and 329.5 mA cm–2 (mass activity, 1785.9 mA mg–1) for HzOR in 0.1 M HClO4 + 10 mM N2H4 and 0.1 M NaOH + 10 mM N2H4 solutions, respectively, which are superior to that of a commercial Au spheres catalyst. This study provides a new insight into electrocatalytic HzOR over Au high-index facets and presents a rational design and synthesis of high-performance electrocatalysts for HzOR.