Photocatalytic CO2 Reduction Mediated by Electron Transfer via the Excited Triplet State of Zn(II) Porphyrin

Abstract

Summary

A photochemical reduction of CO₂ to CO was shown using the zinc porphyrin dyad with a connected rhenium complex (Zn(tBuPP))-(Re(Phen)Br(CO)3) as a combined catalyst and photosensitizer molecule. Turnover numbers (TONs) of >1300 and a selectivity of >99.9% for CO were reached in DMA. The experiments were conducted under visible-light irradiation (λ = 420 nm) using BIH as sacrificial electron donor (see section SEDs below).

Advances and special progress

A selective method for the reduction of CO₂ to CO with a porphyrin-rhenium complex dyad was presented, effectively linking the catalyst and photosensitizer in one molecule.

Content of the published article in detail

The article contains results for the reduction of CO₂ to CO under visible-light catalysis using (Zn(tBuPP))-(Re(Phen)Br(CO)3) as a catalyst and photosensitizer. The catalytic system performs best (referring to the TON of CO production) in DMA.

Catalyst and Photosensitizer

(Zn(tBuPP))-(Re(Phen)Br(CO)3)

Investigation

	cat	cat conc [µM]	e-D	e-D conc [M]	solvent A	additives	.	.	λexc [nm]	.	TON CO	.	.	.	.
1.	(Zn(tBuPP))-(Re(Phen)Br(CO)3)	0.05	BIH	0.05	DMA	phenol			420 nm		910
2.	(Zn(tBuPP))-(Re(Phen)Br(CO)3)	0.075	BIH	0.05	DMA	phenol			420 nm		1340
3.	(Zn(tBuPP))-(Re(Phen)Br(CO)3)	0.05	BIH	0.05	DMA				420 nm		520

Investigation-Name: photocatalytic CO2 conversionExport

Sacrificial electron donor

In this study, the experiments were done with the sacrificial electron donor BIH.

Additives

In this study, PhOH was used as an additive.