Tuning Morphology and Electronic Structure of Cobalt Metaphosphate Via Vanadium-Doping for Efficient Water and Urea Splitting

Designing efficient multifunctional electrocatalysts for water and urea splitting to produce green hydrogen presents a significant yet worthwhile challenge. Herein, the morphology and electronic structure of cobalt metaphosphate (Co2P4O12) by vanadium (V) doping, resulting in improved electrocatalytic activity and stability for hydrogen evolution reaction (HER), oxygen evolution reaction (OER), and urea oxidation reaction (UOR) are simultaneously regulated. Theory calculations show that V-doped Co2P4O12 (V-Co2P4O12) can boost the kinetics of catalytic reactions by optimizing the d-band center of Co atoms and the binding strength of intermediates, as well as enhancing the density of states. Moreover, the doping of V into Co2P4O12 crystalline structure benefits the formation of a thicker amorphous layer during the catalytic process, which could enhance its alkaline corrosion resistance and stability. Additionally, the multilevel nanostructures of V-Co2P4O12 provide rich active sites for catalytic reactions. As a result, a two-electrode electrolyzer assembled by V-doped Co2P4O12 delivers low voltages for overall water and urea splitting. The superior performance suggests that the proposed V-doping strategy is a promising way to regulate electrocatalytic activity for catering to green electrocatalytic applications. The morphology and electronic structure of the Co2P4O12 catalyst are simultaneously regulated by V doping, which endows the catalyst with enhanced hydrogen evolution reaction (HER), oxygen evolution reaction (OER), and urea oxidation reaction (UOR) performance. Thanks to the excellent trifunctional catalytic performance, the assembled two-electrode electrolyzers enable efficient overall water and urea splitting at low overpotentials.image