In situ fabrication of Z-scheme C3N4/Ti3C2/CdS for efficient photocatalytic hydrogen peroxide production.

ABSTRACT

Photocatalysis is a potential technology to produce hydrogen peroxide with low energy consumption and no pollution. However, when using traditional photocatalysts it is hard to meet the requirements of wide visible light absorption, high carrier separation rate and sufficient active sites. Graphitic carbon nitride (g-C3N4) has great potential in the photocatalytic production of hydrogen peroxide, but its photocatalytic performance is limited by a high carrier recombination ratio. Here, we fabricated the Z-Scheme heterojunction of C3N4/Ti3C2/CdS in situ. The large specific surface area of C3N4 can provide plenty of reactive sites, and the absorption efficiency under visible light is improved with the addition of Ti3C2 and CdS. The better conductivity of Ti3C2 reduces the charge transfer resistance. With the increase of surface charge carriers, the width of the space charge region decreases and the photocurrent density increases significantly. Under visible light irradiation, the H2O2 yield of the ternary photocatalyst reaches 256 µM L-1 h-1, which is about 6 times that of pristine C3N4. After three cycles, the high photocatalytic efficiency can still be maintained. In this paper, the reaction mechanism of photocatalytic hydrogen peroxide production by the C3N4/Ti3C2/CdS composite material is proposed through an in-depth study of energy band theory, which provides a new reference for the design and preparation of high-performance materials for photocatalytic hydrogen peroxide production.