Improving the reactivity of unserviceable photoelectrons via Cr-MOF assimilated Bi₂WO₆ redox photocatalyst for CO₂ conversion to valuable fuels

Photocatalytic CO₂ conversion to renewable energy were carried out over photoelectrons to mitigate environmental concerns. However, the unserviceable photoelectrons of Bi₂WO₆ (BWO) deter the process due to its fast recombination and deactivation during the reaction. Herein, MIL-101(Cr)–NH₂ (Cr-MOF) was employed to change the fate of unserviceable photoelectrons of BWO for the conversion of CO₂. This coupling not only reduces the energy barrier for photoelectron transfer but also facilitates the engagement of low-energy unserviceable electrons that would otherwise recombine with their respective high-energy holes in the valence band. Accordingly, strong coupling of BWO@Cr-MOF redox photocatalyst shows an exceptional photocatalytic CO₂ conversion to CO (105 µmol/g) and CH₄ (19 µmol/g), which is approximately seven times higher than BWO and Cr-MOF. Based on the time-resolved photoluminescence, room-temperature electron paramagnetic resonance and electrochemical characterizations, it is apparent that the incomparable photocatalytic performance of the BWO@Cr-MOF redox photocatalyst is certainly attributable to the significantly-enhanced photogenerated charge transfer and separation. The closely-contacted BWO@Cr-MOF redox photocatalyst demonstrates a robust coupling that maintains exceptional stability and selectivity for five consecutive rounds, surpassing numerous reported catalysts.