Self-Adaptive Dual-Site Synergy with an Optimized Electronic Configuration for Overall Water Splitting in Acidic Media

Inharsh acidic environments, there remains a demand for catalyststhat possess both high activity and stability, enabling them to efficientlyenhance the slow kinetics of the hydrogen evolution reaction and oxygenevolution reaction, which are crucial for the advancement of protonexchange membrane water electrolyzers. Herein, a bifunctional electrocatalystwas designed by synergistically modulating the electronic and coordinationproperties. The IrO x /MnO x catalyst was successfully created, surpassing the activityand stability limitations of IrO2 catalysts for acidicoverall water splitting, thereby pushing the boundaries of electrocatalyticperformance. When used as both electrodes in an overall water-splittingcell, the IrO x /MnO x catalyst achieved a current density of 10 mA cm(-2) at 1.51 V for 36 h without any noticeable degradation, which greatlyoutperformed the commercial couples (Pt/C||IrO2, 1.65 V)in acidic media. Of greater significance, X-ray absorption spectroscopydeciphered that the unsaturated Ir centers, which have an electron-richnature, can lower energy barriers associated with the proton adsorptionand desorption and oxygenated reactant species through a self-adaptivesurface reconstruction process. This work introduces an approach toboost the intrinsic performance of catalysts for overall water splittingby constructing unsaturated coordination centers, offering a promisingstrategy for catalyst design. The bifunctionalIrO( x )/MnO x electrocatalystdemonstrates excellent HERand OER for acidic water splitting, which will contribute to the developmentof sustainable energy applications.