Photocatalytic reduction of CO2 into valuable chemicals or fuels is considered a promising solution to mitigate the energy crisis. In this work, efficient CO2 to CO conversion was achieved, accompanied by a class of trinuclear Fe clusters as photocatalysts. Under optimal conditions, the highest catalytic rate could be up to 140.9 μmol/h in 6 h with the assistance of photosensitizers (PS). The trinuclear Fe Clusters can be used as secondary building units to construct Fe-based metal-organic frameworks (MOFs). However, the catalytic activity of Fe-based MOFs is weaker than that of clusters in both the cases of extra PS-assisted MOFs and integrated PS into MOFs. The simpler synthesis, lower cost, and higher catalytic activity make the Fe clusters a better catalyst. Additionally, steady-state fluorescence tests confirmed the transfer of photogenerated electrons from PS to the clusters during the photocatalytic reaction.
Keywords: CO2 reduction; Fe clusters; metal−organic frameworks; photocatalysis; photosensitizers.