Boosting hydrazine oxidation and hydrogen evolution catalysis with anchored Ru clusters by electronically tunable Ru–S–C bonds

Ru clusters have great potential as excellent bifunctional catalysts for the hydrogen evolution reaction (HER) and hydrazine oxidation reaction (HzOR), but suffer from the difficulty of stabilization on the substrate and tuning the electronic environment. Herein, we present Ru clusters supported on N, S co-doped hollow carbon spheres (Ru/NSCS) by elaborately designed Ru–S bonds to anchor Ru clusters and optimize the surrounding coordination environment. The Ru/NSCS exhibits superior electrocatalytic performance for the HER and HzOR, where an ultrasmall overpotential of 40 mV and a working potential of −81 mV at 10 mA cm−2 can be achieved, respectively. The two-electrode system requires an applied voltage of only 26 mV to achieve 10 mA cm−2 and remains stable for 20 hours. Theoretical calculations reveal that the Ru–S bonds induce partial charge transfer from Ru clusters to the N, S co-doped carbon base, thus optimizing the adsorption energy of *H and dehydrogenation intermediates of N2H4.