Hierarchical CeO2/Bi2MoO6 heterostructured nanocomposites for photoreduction of CO2 into hydrocarbons under visible light irradiation

CeO2/Bi2MoO6 heterostructured microspheres with excellent and stable catalytic activity for CO2 photoreduction were successfully synthesized via a solvothermal route. The morphology, porosity, phase, chemical structure, optical and electronic properties of the as-prepared samples are characterized. It is observed that the CeO2/Bi2MoO6 nanocomposites with heterojunction showed greatly increased specific surface area, enhanced response to visible light, promoted charge carrier separation and transfer efficiency. Furthermore, the mechanism of CO2 photoreduction was also investigated. It demonstrates that the CO32−and HCO3− would be the reactive species, proving the thermodynamic feasibility of CO2 photoreduction. Notably, the presence of basic CeO2 on Bi2MoO6 surface dramatically enhances the adsorption ability of CO2, which could be further transferred into b-CO32−and b-HCO3− species as reactive intermediates for the photoreduction reaction. Consequently, introduction of CeO2 could significantly enhance the CO2 photoreduction performance of CeO2/Bi2MoO6 nanocomposites, attributing to the synergistic role of CeO2 as photosensitizer and CO2 adsorbent. The maximum total yield of CH3OH and C2H5OH was 58.4 μmol gcat−1 obtained over 5C-BM, which was about 1.9 and 4.1 times higher than that over pure Bi2MoO6 and pure CeO2. Moreover, the CeO2/Bi2MoO6 nanocomposites exhibit excellent chemical stability and recyclability.