MoS₂ Nanoflower-Deposited g-C₃N₄ Nanosheet 2D/2D Heterojunction for Efficient Photo/Electrocatalytic Hydrogen Evolution

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