Water-Assisted Highly Efficient Photocatalytic Reduction of CO<sub>2</sub> to CO with Noble Metal-Free Bis(terpyridine)iron(II) Complexes and an Organic Photosensitizer
Yanan Wang, Ting Liu, Longxin Chen, Duobin Chao
Abstract
Photocatalytic CO2 reduction reaction is believed to be a promising approach for CO2 utilization. In this work, a noble metal-free photocatalytic system, composed of bis(terpyridine)iron(II) complexes and an organic thermally activated delayed fluorescence compound, has been developed for selective reduction of CO2 to CO with a maximum turnover number up to 6320, 99.4% selectivity, and turnover frequency of 127 min–1 under visible–light irradiation in dimethylformamide/H2O solution. More than 0.3 mmol CO was generated using 0.05 μmol catalyst after 2 h of light irradiation. The apparent quantum yield was found to be 9.5% at 440 nm (180 mW cm–2). Control experiments and UV–vis–NIR spectroscopy studies further demonstrated that water strongly promoted the photocatalytic cycle and terpyridine ligands rather than Fe(II) were initially reduced during the photocatalytic process.