Transforming temperature effects on TiO2/iron oxide composite derived from copper slag as a photocatalyst for glucose conversion

Amorphous copper slag (CS), a by-product of the matte smelting and refining processes in copper smelting, contains approximately 47 % iron. This study explores the potential of using CS as an iron source to create a photocatalyst composite with TiO₂ through calcination at various temperatures (550, 700, 850, and 1000 °C) in order to achieve efficient photocatalytic conversion of glucose to lactic acid under visible light irradiation (λ ≥ 380 nm) at room temperature. All the calcined composites exhibited superior glucose conversion and lactic acid production compared to the uncalcined composite (CT) and pure TiO₂. The composite calcined at 700 °C provided the highest yield and selectivity for lactic acid. This improvement is attributed to the optimal ratio of Ti^(III)/Ti^(IV) and the effective separation of photogenerated electron-hole pairs via the Z-scheme heterojunction in the calcined CT composite. This process contributes to the circular economy by recycling waste materials to produce higher-value-added chemicals from biomass using sustainable energy sources.