Photocatalytic CO2 Reduction Using a Robust Multifunctional Iridium Complex toward the Selective Formation of Formic Acid

Abstract

Summary

A photochemical reduction of CO₂ to formic acid and CO was shown using the iridium complex [Ir(mesbpy-(PCy2)2)][BPh4] (100756) as a catalyst without any additional photosensitizer. Turnover numbers (TONs) of 2080 and a selectivity of 87% for formic acid were reached in dimethylacetamide/water. The experiments were conducted under visible-light irradiation (λ > 400 nm) using BIH as sacrificial electron donor (see section SEDs below).

Advances and special progress

The authors have developed a multifunctional catalyst that allows for selective generation of formic acid without the need for an external photosensitizer.

Additional remarks

The developed catalyst reduces CO2 to CO via inner-sphere catalysis and to formic acid via outer-sphere catalysis.

Content of the published article in detail

The article contains results for the reduction of CO₂ to CO and formic acid under visible-light catalysis using an iridium complex. The catalytic system performs best (referring to the TON of formic acid production) in dimethylacetamide/water.

Catalyst

[Ir(mesbpy-(PCy2)2)][BPh4] (100756)

Investigation

REDIRECT Photocatalytic reduction of CO2, best TONInvestigation-Name: Table 1

Sacrificial Electron Donor

In this study, the experiments were done with the sacrificial electron donor BIH (BIH (100508)).

Additives

In this study, additional control experiments were conducted with Hg.