Experimental and DFT Studies of Au Deposition Over WO(3)/g-C(3)N(4) Z-Scheme Heterojunction

A typical Z-scheme system is composed of two photocatalysts which generate two sets of charge carriers and split water into H(2) and O(2) at different locations. Scientists are struggling to enhance the efficiencies of these systems by maximizing their light absorption, engineering more stable redox couples, and discovering new O(2) and H(2) evolutions co-catalysts. In this work, Au decorated WO(3)/g-C(3)N(4) Z-scheme nanocomposites are fabricated via wet-chemical and photo-deposition methods. The nanocomposites are utilized in photocatalysis for H(2) production and 2,4-dichlorophenol (2,4-DCP) degradation. It is investigated that the optimized 4Au/6% WO(3)/CN nanocomposite is highly efficient for production of 69.9 and 307.3 µmol h(−1) g(−1) H(2) gas, respectively, under visible-light (λ > 420 nm) and UV–visible illumination. Further, the fabricated 4Au/6% WO(3)/CN nanocomposite is significant (i.e., 100% degradation in 2 h) for 2,4-DCP degradation under visible light and highly stable in photocatalysis. A significant 4.17% quantum efficiency is recorded for H(2) production at wavelength 420 nm. This enhanced performance is attributed to the improved charge separation and the surface plasmon resonance effect of Au nanoparticles. Solid-state density functional theory simulations are performed to countercheck and validate our experimental data. Positive surface formation energy, high charge transfer, and strong non-bonding interaction via electrostatic forces confirm the stability of 4Au/6% WO(3)/CN interface. [Image: see text] ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1007/s40820-019-0345-2) contains supplementary material, which is available to authorized users.