In situ growth of vertically aligned ultrathin MoS_2 on porous g-C_3N_4 for efficient photocatalytic hydrogen production

摘要

Ultrathin MoS2 nanosheets are grown in situ on the surface of porous g-C3N4 by a facile solid-state method. HAADF-STEM and HRTEM images show that ultrathin MoS2 (1-3 layers) with a 2H phase vertically stand on (arch bridge-like morphology) the surface of porous g-C3N4. Photoelectrochemical measurements indicate that electrons rapidly migrate from porous g-C3N4 to MoS2 because of the strong interfacial contact formed by in situ growth, thus promoting the separation of photoinduced carriers. The special ultrathin and vertical structures of MoS2 not only shorten the charge migration distance but also expose active edge sites on its surface, facilitating the occurrence of the H-2 evolution reaction. In this study, 2.0% MoS2/porous g-C3N4 (in situ growth) exhibits the highest H-2 evolution rate of 3570 mu mol.h(-1).g(-1) with an apparent quantum yield (AQY) of 8.8% at lambda = 420 nm, which is almost equal to that of 2.0% Pt/porous g-C3N4. This work provides a new design for MoS2 cocatalysts with high performance and provides a deeper understanding of the interfacial transport of carriers between g-C3N4 and MoS2.