In Situ Synthesis of Few-Layered g-C3 N4 with Vertically Aligned MoS2 Loading for Boosting Solar-to-Hydrogen Generation.

Abstract

In artificial photocatalytic hydrogen evolution, effective incident photon absorption and a high-charge recombination rate are crucial factors influencing the overall efficiency. Herein, a traditional solid-state synthesis is used to obtain, for the first time, novel samples of few-layered g-C3 N4 with vertically aligned MoS2 loading (MoS2 /C3 N4 ). Thiourea and layered MoO3 are chosen as precursors, as they react under nitrogen atmosphere to in situ produce the products. According to the quasi-Fourier transform infrared reflectance and X-ray diffraction measurements, the detailed reaction process is determined to proceed through the confirmed formation pathway. The two precursor units MoS2 and C3 N4 are linked by MoN bonds, which act as electronic receivers/conductors and hydrogen-generation sites. Density functional theory is also carried out, which determines that the interface sites act as electron-accumulation regions. According to the photoelectrochemical results, MoS2 /C3 N4 can achieve a current of 0.05 mA cm-2 , which is almost ten times higher than that of bare g-C3 N4 or the MoS2 /C3 N4 -R reference samples. The findings in the present work pave the way to not only synthesize a series of designated samples but also thoroughly understand the solid-state reaction.