Construction of a 0D–2D–2D Sandwich-like\nAg/g‑C<sub>3</sub>N<sub>4</sub>/MoS<sub>2</sub> Photocatalyst\nwith Bidirectional Electron Transfer Channels for Photocatalytic Hydrogen\nEvolution

Hydrogen (H<sub>2</sub>) production\ntechnology has sparked a boom\nin research aimed at alleviating environmental pollution and the pressure\nof nonrenewable energy sources. A key factor in this technology is\nthe use of efficient photocatalysts. In this work, we successfully\nsynthesized a 0D–2D–2D sandwich-like Ag/g-C<sub>3</sub>N<sub>4</sub>/MoS<sub>2</sub> catalyst with bidirectional electron\ntransfer channels via a calcination–hydrothermal method. The\nH<sub>2</sub> evolution reaction of the Ag/g-C<sub>3</sub>N<sub>4</sub>/MoS<sub>2</sub> catalyst under simulated solar light irradiation\nconditions revealed that it achieved a maximum H<sub>2</sub> evolution\nrate of 1061.13 μmol·g<sup>–1</sup>·h<sup>–1</sup>, representing a 43.12-fold improvement over pristine g-C<sub>3</sub>N<sub>4</sub>. Based on systematic characterization with a combination\nof theoretical simulations, time-resolved photoluminescence, and electron\nspin resonance spectra, we demonstrate that the remarkable improvement\nin photocatalytic performance was ascribed to the bidirectional electron\ntransport channels and 0D–2D–2D structure of the ternary\ncatalyst. This unique structure, which was characterized by a large\nspecific surface area, provided numerous active sites for photocatalytic\nreactions. Bidirectional electron transfer channels expedited the\nmigration of photogenerated electrons reaching cocatalysts MoS<sub>2</sub> and Ag from the conduction band of g-C<sub>3</sub>N<sub>4</sub>, consequently enhancing the photocatalytic activity. This study\nhighlights the effectiveness of the bidirectional electron transfer\nchannels in promoting charge carrier migration and suppressing charge\ncarrier recombination for boosting photocatalytic hydrogen evolution\nand provides an efficient strategy for the actual application of g-C<sub>3</sub>N<sub>4</sub>-based photocatalysts.