Bismuth-derived heterojunction photocatalysts for environmental remedies

A wide variety of Bi 3+ -rich materials and their heterojunctions (Bi 3+ -HJs) with various bandgap materials and dopants were summarized to enlarge the sunlight-harvesting response of the photocatalysts that is an effective technique for amplifying the photocatalytic efficiency. Systematically summarized the implementation of innovative approaches such as synthesis, morphology tuning, narrow bandgap materials alignment, doping/defect engineering, crystal-facet exposure, and specific surface area to promote the solar light response, electrical conductivity, mobility of oxygen vacancies, and dispersion/diffusion of electron-holes/charge separation of the as-designed photocatalysts. In the literature, many Bi 3+ materials are used for photocatalytic applications, but they largely focus on individual Bi 3+ compounds such as BiVO 4 , BiMoO 4 , Bi 2 S 3 , BiOX, etc. none of them discuss a comprehensive comparison between different Bi 3+ -rich compounds and their use in photocatalysis. However, atomic-level interactions of the different bandgap materials and uniform distribution of the dopant ions in the Bi 3+ -based host matrices are important for developing more advanced photocatalysts. To maximize photocatalyst potential, a in-depth consideration of the complex exchanges between the host-guest materials, crystalline structure, pH kinetics, photocatalyst doses, working mechanisms, and functionality were reviewed, which are key requirements. A comparative analysis among Bi 3+ -rich compounds in terms of their functionality, crystal phase, electrical conductivity, charge separation, and photocatalytic efficiency was reviewed. Hence, much consideration is necessary to expand the existing photocatalysts' activity to strictly satisfy industrial requirements and for further use in broad industrial applications. Future challenges concerning interfacial charge separation, higher solar-light absorption, long-term chemical stability, and scalable deployment are outlined to lead to the upcoming design of high-performance Bi-derived heterostructures.