P and Se-codopants triggered basal plane active sites in NbS2 3D nanosheets toward electrocatalytic hydrogen evolution

Abstract

Promoting the intrinsic activity and accessibility of basal plane sites in transition metal dichalcogenides (TMDs) is an important way to optimize their catalytic performance for energy conversion and storage. Here, a simple liquid-phase phosphating selenization pyrolysis method is developed to prepare P and Se co-doped niobium disulfide (NbS2) 3D nanosheets with active basal plane for efficient catalyzing hydrogen evolution reaction (HER). Experimental results indicate that the P and Se co-doped NbS2 3D nanosheets exhibit significantly enhanced HER activity and stability compared to their undoped counterparts. It realizes 165 mV decreased overpotential at 10 mA cm−2 and a stable durability over 40 h continuous operation at 14 mA cm−2 without observable fading. Density functional theory (DFT) studies suggest that the P dopant is to activate the adjacent original inert Nb sites, where both S and Nb sites in P, Se co-doped NbS2 monolayer can together act as the active sites for HER. Furthermore, the addition of selenium can stabilize the catalytic activity. Our work provides a promising approach and theoretical framework for improving the electrocatalytic HER performance of NbS2, and may have general guidelines for other transition metal disulfides.