Structural Design of Amorphous CoMoP_x with Abundant Active Sites and Synergistic Catalysis Effect for Effective Water Splitting

Herein, a structural design principle is presented to synthesize amorphous bimetallic phosphides (a-CoMoP_x/CF) to efficiently catalyze water splitting. Porous Co-MOF/CF and defective CoMoO₄/CF are used as structure-inducing templates to introduce rich defects and large voids that facilitate the formation of amorphous a-CoMoP_x/CF. Theoretical calculations reveal a synergistic catalytic mechanism that is based on the bimetallic components. Hierarchical nanosheet arrays combined with amorphous structures provide a superior mass transfer capacity and fully exposed atoms, increasing the electrochemical active surface area (ECSA). The structural advantages and the synergistic catalytic effect of the bimetallic components generate a-CoMoP_x/CF with excellent catalytic activity for the hydrogen evolution reaction (HER), displaying a very low overpotential of 59 mV and delivering a current density of 10 mA cm^-2 under alkaline conditions. A full electrolysis apparatus with a-CoMoP_x/CF as both cathode and anode shows a catalytic performance comparable to that of a noble metal-based catalyst set-up (Pt/C-CF // RuO₂-CF), achieving 10 mA cm^-2 at a potential of 1.581 V and stable operation at 100 mA cm^-2 for more than 100 h. These findings provide a novel concept to design stable structured catalysts based on earth-abundant elements for the large-scale application of electrocatalysis processes related to energy conversion technologies.