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/gcat–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.