Constructing Symmetry-Mismatched Ru x Fe 3- x O 4 Heterointerface-Supported Ru Clusters for Efficient Hydrogen Evolution and Oxidation Reactions.

Ru-related catalysts have shown excellent performance for the hydrogen evolution reaction (HER) and hydrogen oxidation reaction (HOR); however, a deep understanding of Ru-active sites on a nanoscale heterogeneous support for hydrogen catalysis is still lacking. Herein, a click chemistry strategy is proposed to design Ru cluster-decorated nanometer Ru x Fe 3- x O 4 heterointerfaces (Ru/Ru x Fe 3- x O 4 ) as highly effective bifunctional hydrogen catalysts. It is found that introducing Ru into nanometric Fe 3 O 4 species breaks the symmetry configuration and optimizes the active site in Ru/Ru x Fe 3- x O 4 for HER and HOR. As expected, the catalyst displays prominent alkaline HER and HOR performance with mass activity much higher than that of commercial Pt/C as well as robust stability during catalysis because of the strong interaction between the Ru cluster and the Ru x Fe 3- x O 4 support, and the optimized adsorption intermediate (H ad and OH ad ). This work sheds light on a promsing approach to improving the electrocatalysis performance of catalysts by the breaking of atomic dimension symmetry.