Defect-rich MoS2/NiS2 nanosheets loaded on SiNWs for efficient and stable photoelectrochemical hydrogen production

Photoelectrochemical (PEC) reaction with efficient, stable, and cost-effective photocathodes using nonprecious metals will be one of the most environmentally friendly technologies for hydrogen (H2) generation under the worldwide pressure for carbon neutrality. Herein, a new 3-dimentional (3D) SiNWs@MoS2/NiS2 photocathode was designed and synthesized. Defect-rich MoS2/NiS2 nanosheets on silicon nanowires (SiNWs) provide more active sites to promote charge transfer and photo-generated electron-hole separation. Meanwhile, the 3D structure of the photocathode provides an effective charge transfer mode and an open channel for rapid H2 release. The SiNWs@MoS2/NiS2 photocathode exhibits the maximum photocurrent density (21.4 mA center dot cm-2 at 0.9 V vs. RHE), highest H2 production rate (183 lmol center dot h-1), smallest diffusion resistance (34.7 X), and excellent catalytic stability for more than 10 h at pH = 7. Based on density function theory calculation, the MoS2/NiS2 nanosheets are conducive to chem-ical adsorption of H2 intermediates, which are crucial for the maintenance of the composite photocathode in PEC H2 production. (c) 2022 Published by Elsevier Inc.