Abstract
Photocatalytic CO2 reduction offers a dual benefit of mitigating greenhouse gas emissions while generating renewable fuels. In this study, a composite photocatalyst based on aluminum-doped strontium titanate (Al-STO) was synthesized via a flux method and modified with dual cocatalysts: metallic Ag (reductive site) and a Ni-based species (oxidative site). Sequential photodeposition enabled precise loading, yielding a catalyst with enhanced charge separation and suppressed recombination. Structural and spectroscopic analyses confirmed the uniform dispersion of cocatalysts and broadened light absorption into the visible range. Photocatalytic evaluation under simulated solar light revealed a more than twofold increase in CO production (24.2 µmol·g⁻¹·h⁻¹) and high selectivity (up to 99%), compared to pristine Al-STO. The observed performance enhancement is attributed to the synergistic interaction between Ag and the Ni-based cocatalyst, enabling spatially resolved charge carrier pathways. These results highlight the promise of cocatalyst engineering on perovskite surfaces for selective CO2-to-fuel conversion under solar irradiation.