Visible light driven reduction of CO2 catalyzed by an abundant manganese catalyst with zinc porphyrin photosensitizer

Abstract

Summary

A photochemical reduction of CO₂ was shown using the manganese catalyst Mn(bpy)(CO)3Br and the zinc photosensitizer ZnTPP. Turnover numbers (TONs) of 64 and 16 were reached after 180 min of irradiation for CO and formic acid, respectively. The experiments were performed using a Xenon lamp as the light source.

Advances and special progress

Photochemical CO₂ conversion in an environmentally friendly and sustainable photocatalytic system using earth abundant metal complexes efficiently yielded CO and HCOOH in aqueous acetonitrile solution.

Additional remarks

The manganese catalyst and the zinc photosensitizer were used in different ratios, resulting in different TONs for CO and HCOOH production.

Content of the published article in detail

The article contains results for the reduction of CO₂ to CO and HCOOH using different ratios of the catalyst and photosensitizer. The catalytic system performed best (referring to the TONs of CO and HCOOH production) for the catalyst:photosensitizer ratio of 4:1.

Catalyst

Mn(bpy)(CO)3Br

Photosensitizer

ZnTPP

Investigation

	cat	cat conc [µM]	PS	PS conc [mM]	e-D	e-D conc [M]	solvent A	.	.	λexc [nm]	.	TON CO	TON HCOOH	.
1.	Mn(bpy)(CO)3Br	2	ZnTPP	0.5	TEA	0.1	MeCN			xenon lamp		119	19
2.	Mn(bpy)(CO)3Br	1.5	ZnTPP	0.5	TEA	0.1	MeCN			xenon lamp		97	18
3.	Mn(bpy)(CO)3Br	0.5	ZnTPP	0.25	TEA	0.1	MeCN			xenon lamp		64	16
4.	Mn(bpy)(CO)3Br	0.5	ZnTPP	0.5	TEA	0.1	MeCN			xenon lamp		12	10
5.	Mn(bpy)(CO)3Br	0.5	ZnTPP	1	TEA	0.1	MeCN			xenon lamp		8	6
6.	Mn(bpy)(CO)3Br	0.5			TEA	0.1	MeCN			xenon lamp		2	1
7.			ZnTPP	0.5	TEA	0.1	MeCN			xenon lamp

Investigation-Name: Table 1Export

Sacrificial electron donor

In this study, triethylamine (TEA) was used as sacrificial electron donor.

Additives

In this study, no additives were used.