Plasmonic Bi Metal Deposition and g-C3N4 Coating on Bi2WO6 Microspheres for Efficient Visible-Light Photocatalysis

A low-cost semiconductor-based photocatalyst using visible light energy has attracted increasing interest for energy generation and environmental remediation. Herein, plasmonic Bi metal was deposited in situ in g-C3N4@Bi2WO6 microspheres via a hydrothermal method. As an electron-conduction bridge, metallic Bi was inserted as the interlayer between g-C3N4 and the surface of Bi2WO6 microspheres to enhance visible light absorption due to the surface plasmon resonance (SPR) effect and facilitate efficient electron-carrier separation. Different characterization techniques, including XRD, SEM, TEM, UV–vis, XPS, photoluminescence, and photocurrent generation, were employed to investigate the morphology and optical properties of the as-prepared samples. The results indicated that the g-C3N4(20%)@Bi@Bi2WO6 microsphere sample exhibited an extraordinary enhanced photocatalytic activity, higher than those of the g-C3N4, Bi2WO6, and g-C3N4(20%)@Bi2WO6 samples. It implies that the heterostructured combination of g-C3N4, metallic Bi, and Bi2WO6 microspheres provided synergistic photocatalytic activity via an efficient electron transfer process. On the basis of the results, a possible photocatalytic mechanism of the as-prepared samples was proposed. The present study demonstrated the feasibility of utilizing low-cost metallic Bi as a substitute for noble metals to design a doped photocatalysis composite with enhanced photocatalytic performance.