Development of high performing UiO-67/BiFeO3 photocatalyst for selective CO2 conversion to methanol: Process optimization by RSM

The continuous rise in atmospheric CO 2 levels due to industrialization has raised pressing environmental concerns, necessitating efficient carbon capture and utilization strategies. Among them, the photocatalytic reduction of CO 2 to methanol offers a sustainable approach that mitigates emissions while producing a valuable solar fuel. Metal-organic frameworks (MOFs) have emerged as promising photocatalysts due to their high surface area, tunable porosity, and dense active sites, though their wide bandgaps limit visible-light activity. In this study, a UiO-67/BiFeO 3 composite photocatalyst was synthesized via a wet chemical method, combining BiFeO 3 's narrow bandgap with the structural advantages of UiO-67. Photocatalytic tests under visible light showed a significant improvement in methanol production, with the composite achieving 93.99 μmol/g·h after 4 h outperforming pure UiO-67 (31.29 μmol/g·h) and BiFeO 3 (8.01 μmol/g·h). To optimize reaction conditions, Response Surface Methodology (RSM) and Box–Behnken design (BBD) were employed. The resulting model (R 2 = 0.9966) identified an optimal methanol production rate of 95.06 μmol/g·h with a desirability value of 1.000. These findings highlight the synergistic role of BiFeO 3 's light absorption and UiO-67's CO 2 adsorption, showcasing the potential of RSM in optimizing MOF-based photocatalytic systems for sustainable CO 2 conversion. • UiO-67/BiFeO 3 composite photocatalysts were synthesized via a wet chemical method. • The composite showed enhanced visible-light absorption and CO 2 adsorption capacity. • Applied RSM with Box–Behnken Design to optimize CO 2 -to-methanol photoreduction. • Achieved a methanol production rate of 95.06 μmol/g·h with only 1.80 % prediction error. • Demonstrated strong synergy between catalyst design and statistical optimization tools.