MoS₂ Nanoflower-Deposited g‑C₃N₄ Nanosheet\n2D/2D Heterojunction for Efficient\nPhoto/Electrocatalytic Hydrogen Evolution

Abstract

The\ndevelopment of heterostructures for precise electron-transfer\npaths at the p–n junction interface is of great significance\nfor photo/electrocatalytic (EC) applications. In this paper, we have\npresented a strategy to precisely transfer electrons from the conduction\nband of MoS₂ to the valence band site of g-C₃N₄ through a Z-scheme manner. The heterostructure demonstrated\na 2-fold improvement in catalytic efficiency at 20 wt % MoS₂/g-C₃N₄ (18.04 mmol/g_cat^–1) with an apparent quantum yield\n(AQY) of H₂ generation approaching 34% by using a 300 W\nXe lamp. The enhanced photocatalytic (PC) H₂ evolution\nof the heterostructure catalyst shows that the addition of MoS₂ NSs causes more active sites and the prevention of electron–hole\npair recombination by facilitating an increased rate of electron transport\nat the interface. In addition, MoS₂/g-C₃N₄ required the lowest overpotentials of 410 and 262 mV to reach\n20 mA cm^–2 current density for the OER and HER performances,\nrespectively. Subsequently, impedance spectroscopy indicates low charge\ntransfer resistance, and photoluminescence analysis showed better-photogenerated\ncharge transfer kinetics for the heterostructures, which contributed\nto their improved photo/electrochemical performance. For intriguing\nphotocatalytic applications in the future, this study offers a path\nfor designing and synthesizing a chemically linked Z-scheme interface\nwith atomic accuracy. Further, the postphoto/electrocatalytic characterizations\nrevealed the intact geometry of the catalyst, indicating the long-term\ndurability of the catalyst.