Vertically Aligned Amorphous NiCoMoP Nanosheets Inlaid with Crystalline NiCoMoP Nanoparticles for Enhanced Overall Water Splitting

Vertically aligned nanosheets generally show superior electrocatalytic activity because stacking is effectively avoided during electrode preparation. However, the preparation of vertically aligned metal phosphide nanosheets is quite a challenge because of the destruction of nanosheet morphology during phosphorization. Here, vertically aligned amorphous NiCoMoP nanosheets inlaid with crystalline NiCoMoP nanoparticles (c/a-NiCoMoP) are successfully prepared by growing NiCo-LDH directly on nickel foam, followed by Mo-doping and phosphorization. Benefiting from its vertically aligned morphology and crystalline/amorphous interface, c/a-NiCoMoP shows superior activity in the HER and OER in both alkaline and neutral media. The c/a-NiCoMoP-based alkaline electrolyzer requires a cell voltage of only 1.569 V to achieve a current density of 10 mA cm–2 without any observable degeneration during 24 h of testing. The outstanding bifunctional performance of c/a-NiCoMoP for overall water splitting is also revealed by density functional theory calculations.