Few-layered MoS₂ anchored on 2D porous C₃N₄ nanosheets for Pt-free photocatalytic hydrogen evolution

The Pt-free photocatalytic hydrogen evolution (PHE) has been the focus in the photocatalytic field. The catalytic system with the large accessible surface and good mass-transfer ability, as well as the intimate combination of co-catalyst with semiconductor is promising for the promotion of the application. Here, we have reported the design of the two-dimensional (2D) porous C₃N₄ nanosheets (PCN NS) intimately combined with few-layered MoS₂ for the high-effective Pt-free PHE. The PCN NS were synthesized based on peeling the melamine–cyanuric acid precursor (MC precursor) by the triphenylphosphine (TP) molecular followed by the calcination, mainly due to the matched size of the (100) plane distance of the precursor (0.8 nm) and the height of TP molecular. The porous structure is favorable for the mass-transfer and the 2D structure having large accessible surface, both of which are positive to promote the photocatalytic ability. The few-layered MoS₂ are grown on PCN to give 2D MoS₂/PCN composites based on anchoring phosphomolybdic acid (PMo₁₂) cluster on polyetherimide (PEI)-modified PCN followed by the vulcanization. The few-layered MoS₂ have abundant edge active sites, and its intimate combination with porous PCN NS is favorable for the faster transfer and separation of the electrons. The characterization together with the advantage of 2D porous structure can largely promote the photocatalytic ability. The MoS₂/PCN showed good PHE activity with the high hydrogen production activity of 4,270.8 μmol·h⁻¹·g⁻¹ under the simulated sunlight condition (AM1.5), which was 7.9 times of the corresponding MoS₂/bulk C₃N₄ and 12.7 times of the 1 wt.% Pt/bulk C₃N₄. The study is potentially meaningful for the synthesis of PCN-based catalytic systems.