A Zn and Pd co-modified TiO₂ photocatalyst exhibits remarkably enhanced photocatalytic activity upon reduction of CO₂ into CH₄. Owing to the synergistic effect of unique O–Zn–Cl and O–Pd–O species, TiO₂–PdX–ZnY presents enhanced visible absorption and efficient charge carrier separation. It can be deduced from theoretical calculations and experimental results that the energy levels of O–Zn–Cl and O–Pd–O satisfy the redox potential of CO₂ reduction, improving the photocatalytic performance. These results suggest that introducing multi-surface species to produce synergetic effects is a feasible route for efficient photocatalysis.