Bridged Mn─O─Ru Motifs in RuO2 Catalyst Promoting Hydrogen Production at Ampere‐Level Current Density

A local oxidation-state asymmetric Mn─O─Ru bridged moiety is incorporated into RuO₂ matrix, successfully constructing a highly efficient Mn-RuO₂ electrocatalyst. Profitted by the preciously regulation of active sites at the bridged motifs, Ru sites exhibit the strongest capacity of H₂O adsorption, and bridged oxygen atoms show optimal H^* adsorption free energy. Therefore, the bridged Mn─O─Ru moiety endows Mn-RuO₂ with outstanding HER performance.

Abstract

Accurately regulating the reactive sites of catalysts is vital for highly efficient catalytic processes but still faces considerable challenges. In view of this, a local oxidation-state asymmetric Mn-O-Ru bridged moiety is developed by introducing Mn atoms into the RuO₂ host. The synergistic effect of the respective active sites on the Mn-O-Ru microstructure ensures its excellent alkaline HER performance. Theoretical calculations profiled that induced by the Mn-O-Ru bridged moiety, the water dissociation ability of Ru sites is significantly boosted, while the bridging oxygen exhibits the optimal hydrogen adsorption free energy. As predicted, the Mn-RuO₂ catalyst achieved the overpotentials as low as 118 and 160 mV at the industrial level current densities of 1 and 2 A cm^‒2 in 1 m KOH, respectively, superior to the RuO₂ and commercial Pt/C catalyst. Such a Mn-RuO₂ electrocatalyst can operate stably with a long lifetime of 300 h at 10 mA cm^‒2 under alkaline conditions. Furthermore, it only requires 1.87 V to reach the current density of 1.0 A cm^‒2 when serving as the cathode in an assembled flow cell. This work provides new insight into catalytic local environment design for obtaining ideal efficient HER electrocatalysts.