Engineering NiS/Ni₂P Heterostructures for Efficient Electrocatalytic Water Splitting

Abstract

Developing high-active and low-cost bifunctional materials for catalyzing the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) holds a pivotal role in water splitting. Therefore, we present a new strategy to form NiS/Ni₂P heterostructures. The as-obtained NiS/Ni₂P/carbon cloth (CC) requires overpotentials of 111 mV for the HER and 265 mV for the OER to reach a current density of 20 mA cm^-2, outperforming their counterparts such as NiS and Ni₂P under the same conditions. Additionally, the NiS/Ni₂P/CC electrode requires a 1.67 V cell voltage to deliver 10 mA cm^-2 in a two-electrode electrolysis system, which is comparable to the cell using the benchmark Pt/C||RuO₂ electrode. Detailed characterizations reveal that strong electronic interactions between NiS and Ni₂P, abundant active sites, and smaller charge-transfer resistance contribute to the improved HER and OER activity.