Band Structure Engineering of BaSrTiO₃-ZnO Composites for Improved Water Splitting Performance

Barium strontium titanate (BaSrTiO₃) and zinc oxide (ZnO) composites as photocatalysts for hydrogen production through water splitting is the promising composite material because of the synergistic effects of its components. BaSrTiO₃ has a strong built-in electric field that helps separate charge carriers, while ZnO offers high electron mobility. The formation of a heterojunction at their interface improves charge transfer and reduces electron-hole recombination, which are major limitations in other systems. The BST@ZnO composites demonstrated markedly enhanced photocatalytic performance, with 3% and 5% samples showing the highest photocurrent density (~2.8 mAcm⁻²) due to efficient charge separation and low charge-transfer resistance. Electrochemical analyses confirmed improved carrier mobility and interfacial conductivity, validating the role of engineered heterojunctions in accelerating HER kinetics. Although OER activity remained limited, the composites exhibit excellent potential for hydrogen-focused photocatalytic applications, bridging material design with sustainable energy generation.