Construction of a 0D–2D–2D Sandwich-like Ag/g-C3N4/MoS2 Photocatalyst with Bidirectional Electron Transfer Channels for Photocatalytic Hydrogen Evolution

Hydrogen (H₂) production technology has sparked a boom in research aimed at alleviating environmental pollution and the pressure of nonrenewable energy sources. A key factor in this technology is the use of efficient photocatalysts. In this work, we successfully synthesized a 0D-2D-2D sandwich-like Ag/g-C₃N₄/MoS₂ catalyst with bidirectional electron transfer channels via a calcination-hydrothermal method. The H₂ evolution reaction of the Ag/g-C₃N₄/MoS₂ catalyst under simulated solar light irradiation conditions revealed that it achieved a maximum H₂ evolution rate of 1061.13 μmol·g^-1·h^-1, representing a 43.12-fold improvement over pristine g-C₃N₄. Based on systematic characterization with a combination of theoretical simulations, time-resolved photoluminescence, and electron spin resonance spectra, we demonstrate that the remarkable improvement in photocatalytic performance was ascribed to the bidirectional electron transport channels and 0D-2D-2D structure of the ternary catalyst. This unique structure, which was characterized by a large specific surface area, provided numerous active sites for photocatalytic reactions. Bidirectional electron transfer channels expedited the migration of photogenerated electrons reaching cocatalysts MoS₂ and Ag from the conduction band of g-C₃N₄, consequently enhancing the photocatalytic activity. This study highlights the effectiveness of the bidirectional electron transfer channels in promoting charge carrier migration and suppressing charge carrier recombination for boosting photocatalytic hydrogen evolution and provides an efficient strategy for the actual application of g-C₃N₄-based photocatalysts.