Selective and Efficient Photocatalytic CO2 Reduction to CO Using Visible Light and an Iron-Based Homogeneous Catalyst

Abstract

Summary

The photochemical reduction of CO₂ to CO was shown using the iron complex Fe(DHPP)Cl in combination with the photosensitizers Ir(ppy)3 or 9-Anthracenecarbonitrile. Turnover numbers (TONs) of up to 140 and a selectivity of 93% for CO were reached in acetonitrile after 55 h of irradiation. The experiments were conducted under visible-light irradiation (λ > 400 nm) with TEA (see section SEDs below) as sacrificial electron donor.

Advances and special progress

The authors reported one of the highest TONs in homogeneous photocatalysis at that time in this study without detecting significant degradation of the catalyst or sensitizer. In addition, they reported the use of a cheap organic photosensitizer for CO2 conversion with a slightly lower TON (60), but higher selectivity (100%).

Content of the published article in detail

The article contains results of a study for the reduction of CO₂ to CO using an iron complex and an iridium-based or organic photosensitizer. The catalytic system performs best (referring to the TON of CO production) in acetonitrile with photosensitizer Ir(ppy)3.

Catalyst

Fe(DHPP)Cl

Photosensitizer

Ir(ppy)3 9-Anthracenecarbonitrile

Investigation

	cat	cat conc [µM]	PS	PS conc [mM]	e-D	e-D conc [M]	solvent A	.	.	TON CO	.
1.	Fe(DHPP)Cl	0.002	Ir(ppy)3	0.2	TEA	0.36	MeCN			140
2.	Fe(DHPP)Cl	0.002	Molecule:100936	0.2	TEA	0.36	MeCN			40
3.	Fe(DHPP)Cl	0.002	Molecule:100936	0.2	TEA	0.05	MeCN			60

Investigation-Name: photocatalytic conversion of CO2 to COExport

Sacrificial electron donor

In this study, the experiments were done with the sacrificial electron donor TEA (TEA).

Additives

In this study, no additives were tested.