Bi2WO6‐based Z-scheme photocatalysts: Principles, mechanisms and photocatalytic applications

• DOI: 10.1016/j.jece.2022.107838
• Publication Date: 2022-05-05T17:42:23Z
• Authors: Tamer M. Khedr; Kunlei Wang; Damian Kowalski; Said M. El-Sheikh; Hany M. Abdeldayem; Bunsho Ohtani; Ewa Kowalska
• Keywords: Environmental purification; energy conversion; Z-scheme photocatalyst; Solar photocatalysis; Green energy; Organic synthesis; 02 engineering and technology; 430; 0210 nano-technology; coupled semiconductors

The development of novel photocatalysts for efficient utilization of solar energy is highly essential for the most critical humanitarian challenges, i.e., energy and water crises as well as environmental pollution. Bismuth tungstate (Bi2WO6), an outstanding Aurivillius phase perovskite, has attracted intensive attention as a visiblelight-responsive photocatalyst because of its non-toxicity, low cost, and outstanding physicochemical characteristics, i.e., nonlinear dielectric susceptibility, ferroelectric piezoelectricity, pyroelectricity, catalytic behavior, modifiable morphology, strong oxidation power, and good photochemical stability. However, the photocatalytic activity of bare Bi2WO6 is restricted because of the inherent drawbacks such as poor light-harvesting efficiency, weak reduction potential, relatively low specific surface area, the fast recombination rate of photoinduced charge carriers, and thus poor quantum yields of photocatalytic reactions. Moreover, the impossibility of simultaneous strong redox ability (demanding wide bandgap) and high light-harvesting efficiency (requiring narrow bandgap) is considered as a big challenge for the practical application of Bi2WO6. Undeniably, the construction of Z-scheme photocatalytic systems is recommended strategy to overcome the above-mentioned disadvantages because of the efficient spatial separation of photogenerated charge carriers and the boosting the redox performance. This review summarizes the principles and recent developments on Z-scheme photocatalytic systems with special emphasis on the Bi2WO6-based photocatalysts, including the types, photocatalytic mechanisms and practical applications. Moreover, major differences between type-II heterojunction and Z-scheme photocatalyst have also been discussed. Additionally, the significant role of unique structures (e.g., core-shell and 2D/2D) for the improvement of photocatalytic activity of Z-scheme photocatalyst has been presented. Indeed, Bi2WO6-based Zscheme photocatalysts have exhibited superior ...