Nanoarchitectonics of La-Doped Ni3S2/MoS2 Hetetostructural Electrocatalysts for Water Electrolysis

Abstract

MoS2 with 2D structure shows efficient hydrogen evolution reaction (HER) performance because undercoordinated Mo–S edges have ideal hydrogen adsorption free energy. MoS2 usually does not satisfy the bifunctional catalysts because of the poor intrinsic oxygen evolution reaction (OER) catalytic activity. Herein, it is proposed to construct heterostructure with OER active components to induce efficient bifunctional catalytic activity along with heteroatom doping to modify the electronic structure to optimize the adsorption and desorption capabilities of reaction intermediates. La-doped Ni3S2/MoS2 grown on nickel foam (La-NMS@NF) is synthesized as bifunctional catalyst taking advantage of the excellent OER performance of Ni3S2. La-NMS@NF evolves into nanoflower-like structures with the addition of La dopant, which provides abundant pore channels to facilitate mass transfer and exposure of active sites. Density functional calculations reveal that the La-doped Ni3S2/MoS2 heterointerface can optimize the water adsorption and H* adsorption/desorption, improving the HER performance. The La-NMS@NF exhibits an overpotential of 154 and 300 mV for HER and OER at 100 mA cm−2 in 1.0 m KOH. Herein, a heteroatom-driven heterostructure activation strategy for electron rearrangement and structural evolution in electrocatalysts to decrease energy consumption in overall water splitting is demonstrated.