Phosphorus doped nickel-molybdenum aerogel for efficient overall water splitting

Developing cost-effective bifunctional water splitting electrocatalyst is of significant importance for clean energy applications. Herein, we reported a P-doped Ni-Mo bimetal aerogel (Ni-Mo-P) through facile Ni-Mo aerogel gelation followed by in-situ P doping with NaH2PO4. The optimized Ni-Mo-P catalyst demonstrated impressively low overpotentials of 69 mV and 235 mV for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) at a current density of 10 mA cm−2. The excellent HER and OER performance was attributed to the electron redistribution triggered by Mo alloying and P doping as well as the optimal bond strength between H* and the active sites. Density functional theory (DFT) calculations revealed that Ni-Mo-P exhibited a reduced energy barrier and much easier water dissociation originated from the electron redistribution by P doping. Benefiting from these advantages, Ni-Mo-P required a low cell voltage of 1.46 V to achieve an overall water splitting current density of 10 mA cm−2.