Design for all-round PHE/HER/OER sandwich nanostructure catalyst: Ultrathin nanosheet ZnIn2S4-encapsulated rich-Mo edge active site Mo2C-N Schottky junction

The development of efficient multifunctional catalyst remains a huge challenge due to their unsatisfactory oxygen/hydrogen intermediate species adsorption, ineffective kinetics rate, lack of active reaction sites. Herein, rich-Mo edge active sites in the molybdenum carbide (Mo2C) were created through nitrogen doping, which was used as cocatalyst to enhance the hydrogen evolution reaction (HER), oxygen evolution reaction (OER) and photocatalytic hydrogen evolution (PHE) of ZnIn2S4 (ZIS). Mo2C-N/ZIS affords a remarkable HER activity with a low overpotential of 74 mV as well as excellent OER activity with a reduced overpotential of 250 mV at 10 mA·cm-2. The formed Schottky junction between Mo2C-N/ZIS are responsible for the enhanced PHE/HER/OER activity, which owns double transfer route beneficial to enhancing separation of photogenerated carriers and reducing bulk/surface recombination of ZIS. Specially, the density functional theory (DFT) calculations demonstrate that Mo2C-N/ZIS Schottky junction with optimal absorption energy for the hydrogen and oxygen intermediates.