Z-scheme g-C3N4/ZnO heterojunction decorated by Au nanoparticles for enhanced photocatalytic hydrogen production

The construction of heterojunction photocatalysts is an effective and widespread approach to solving global environmental issues. Herein, we designed and fabricated a Z-scheme g-C3N4/ZnO/Au heterojunction using a simple chemical method for photocatalytic H-2 production under UV-Visible light irradiation. The g-C3N4/ZnO/Au-2 composite has an optimal photocatalytic H-2 production rate of 46.46 mu mol.g(-)(1).h(-1), representing 25.2-fold and 30.4-fold enhancements compared with a g-C3N4/ZnO-2 composite and bare g-C3N4, respectively. The decorated Au nanoparticles not only enhance the absorption of visible light by the LSPR effect, but also act as an electron mediator to accelerate the electrons transfer from ZnO to g-C3N4. The improved photocatalytic activity of the g-C3N4/ZnO/Au-2 composite can be attributed to the effectively suppressed recombination of photogenerated electron and hole pairs. The mechanism of the photocatalytic hydrogen evolution process had been studied by UV-vis diffuse reflectance spectroscopy (UV-vis DRS), Ultraviolet photoemission spectroscopy (UPS), photoluminescence (PL), transient photocurrent responses, electrochemical impedance spectroscopy (EIS), and electron spin resonance (ESR). This work provides a strategy for the design and synthesis of an environmentally friendly Z-scheme heterojunction for photocatalytic H-2 evolution applications.

Automated summary

The construction of heterojunction photocatalysts is an effective method to solve global environmental issues. In this study, a g-C3N4/ZnO/Au heterojunction was designed and fabricated using a simple chemical method for photocatalytic H2 production. The results showed that the decorated Au nanoparticles enhanced the photocatalytic activity by effectively suppressing the recombination of photogenerated electron-hole pairs.