Copper-doped Bi2MoO6 with concurrent oxygen vacancies for enhanced CO2 photoreduction†

Photocatalytic CO₂ reduction into highly valued chemical fuels holds great promise for resolving the issues related to energy shortage and mitigating greenhouse gas problems. However, the CO₂ conversion efficiency of current photocatalysts is hampered by their undesirable charge transfer and deficient reactive sites. Herein, we synthesized Bi₂MoO₆ doped with monovalent Cu with accompanying O vacancies (Ov) to accelerate bulk and surface charge separation and transfer. Moreover, the Cu dopants serving as reactive sites could improve the adsorption and activation of CO₂ molecules on the catalyst's surface. As a result, the Cu-doped Bi₂MoO₆ catalysts exhibit remarkedly boosted CO₂ reduction activity to the pristine Bi₂MoO₆, and the peak activity reaches at Bi₂MoO₆–10% Cu with a CO evolution rate of 11.40 μmol g⁻¹ h⁻¹ under 300 W Xenon lamp irradiation, without any cocatalyst or sacrificial agent. This photoactivity surpasses that of most previously reported catalysts, and it is about 6-fold higher than that of Bi₂MoO₆ (1.94 μmol g⁻¹ h⁻¹). Moreover, even under natural sunlight illumination, Bi₂MoO₆–10% Cu exhibited considerable activity for CO₂ photocatalytic conversion into CO. This study may inspire an efficient strategy for designing and developing high performance photocatalysts toward CO₂ conversion.