Construction of an efficient bifunctional amorphous MoOx electrocatalyst for HER/UOR reactions through ruthenium doping-induced electronic structure modulation

Electrochemical water splitting represents a sustainable pathway for hydrogen production. However, its widespread application is hindered by the high cost of platinum-based catalysts required for the hydrogen evolution reaction (HER) and the substantial energy input associated with the sluggish oxygen evolution reaction (OER). The urea oxidation reaction (UOR), with a theoretical potential as low as 0.37   V vs. RHE, presents an energetically favourable alternative. Nevertheless, its practical implementation is challenged by a complex six-electron transfer process, necessitating highly active catalysts. While state-of-the-art Ru- or Mo-based catalysts often depend on intricate synthetic routes or the construction of crystalline heterostructures, this study introduces a distinct strategy: the fabrication of Ru-doped amorphous molybdenum oxide (Ru-MoO x /NF) via a facile one-step electrodeposition method. Density functional theory (DFT) calculations reveal strong electronic interactions between Ru and the amorphous framework termed “electron-amorphous synergy” which effectively tunes the electronic structure and markedly enhances catalytic activity toward both HER and UOR. Remarkably, when employed in a dual-electrode urea-assisted electrolytic system, the catalyst achieves a current density of 10   mA   cm -2 at an exceptionally low cell voltage of 1.323   V and maintains stable performance over 30   hours at this current density, surpassing numerous previously reported bifunctional catalysts. This work highlights the great potential of manipulating the amorphous structure through atomic doping as a simple yet effective strategy, distinct from crystalline heterointerface engineering, for designing high-performance bifunctional electrocatalysts.