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

Abstract

Photocatalytic CO2 reduction into highly-valued chemical fuels holds great promises for resolving the energy shortage and mitigating the greenhouse gas. But the current CO2 conversion efficiency is hampered by the undesirable charge transfer and deficient reactive sites of photocatalysts. Herein, we synthesize Bi2MoO6 doped by monovalence Cu with accompanying O vacancies (Ov) to accelerate the bulk and surface charge separation and transfer. Moreover, the Cu dopants serving as the reactive sites improve the adsorption and activation of CO2 molecules on 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 most of the 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, the Bi2MoO6-10% Cu also exhibits considerable activity for CO2 photocatalytic conversion to CO. This study may inspire an efficient strategy for designing and developing high performance photocatalysts toward CO2 conversion.