Advances in bismuth titanate (Bi12TiO20)-based photocatalysts for environmental remediation: Fundamentals and practical applications

Solar irradiance is a renewable energy source that can be utilized to generate electricity and accelerate chemical reactions. However, the actual process conversion productivity is limited which is governed by the migration and separation of photoinduced carriers. To heighten the conversion efficacy, it would be necessary to suppress the EHP recombination and expand the low redox potentials. However, nowadays, countless semiconductor-based photocatalysts have been studied with good photocatalytic activity and superior charge carrier separation. Here, we review Bi-based semiconductor photocatalyst mainly sillenite Bi12TiO20 (band gap ranging from 2.3 to 3.2 eV) with improved photocatalytic activity. However, like other single photocatalysts, Bi12TiO20 (BTO) also exhibits a few shortcomings such as rapid recombination, inadequate visible light absorption, and restriction of the broader-range applicability of BTO. So, to overcome these constraints we have focused on appropriate strategies like doping, and heterojunctions including conventional, Z-scheme, and S-scheme along their mechanism. Furthermore, synthesis methods such as chemical solution decomposition, hydrothermal, and microwave methods are discussed to study the morphology and structural properties of the BTO photocatalyst. The DFT studies are also deliberated to examine the optoelectronic, and structural properties of BTO photocatalyst. Lastly, we concluded with photocatalytic applications such as dyes and antibiotics degradation, NO removal, phenol degradation, and other pollutants degradation over BTO heterojunctions. The concluding remarks with future challenges/perspectives are also discussed.