Dual modulation steering electron reducibility and transfer of bismuth molybdate nanoparticle to boost carbon dioxide photoreduction to carbon monoxide

Owing to the exorbitant CO 2 activation energy and unsatisfactory photogenerated charge separation efficiency, CO 2 photoconversion still faces enormous challenges. In this study, a directional electron transfer channel has been established by decorating N-doped carbon quantum dots (N-CQDs) on the surface of Bi 4 MoO 9 nanoparticles to ensure that more active electrons can participate in the CO 2 reduction. The conduction band of Bi 4 MoO 9 nanoparticles is calculated to be −1.55 eV versus the normal hydrogen electrode (NHE), pH = 7, which is negative enough to attain the photocatalytic CO 2 reduction potential of −0.53 eV versus NHE, pH = 7. CO 2 adsorption curves and in situ Fourier transform infrared spectra reveal that N-CQDs facilitate surface CO 2 adsorption and activation, as well as CO desorption. In addition, steady-state photoluminescence and photoelectrochemical tests prove that the charge separation efficiency can be greatly enhanced by constructing N-CQDs/Bi 4 MoO 9 composites. In the presence of pure water, N-CQDs/Bi 4 MoO 9 -2 composite achieved a CO yield of 16.22 μmol g −1 after 5 h Xe light illumination, which was 3.24 times higher than that of pure Bi 4 MoO 9 (4.98 μmol g −1 ). This study offers a distinctive approach to the optimization of Bi 4 MoO 9 photocatalysts and their application in energy conversion.