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

Abstract 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 CoMoO 4 /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 // RuO 2 ‐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.