Photocatalytic Reduction of CO2 by Highly Efficient Homogeneous FeII Catalyst based on 2,6-Bis(1’,2’,3’-triazolyl-methyl)pyridine. Comparison with Analogues.

Abstract

Summary

A photochemical reduction of CO₂ to CO was shown using the iron complex 100941 as catalyst in combination with the copper photosensitizer 100940. Turnover numbers (TONs) of 576 and a selectivity of 67% for CO were reached in MeCN/TEOA. The experiments were conducted under visible-light irradiation (λ = 420 nm) using BIH as sacrificial electron donor (see section SEDs below). The homoleptic iron complex 100942 and the cobalt complexes 100944 and 100945 were tested for CO₂ reduction as well, but did not show substantial conversion of CO₂ to CO.

Advances and special progress

The authors reported a iron complex with one of the highest activities for CO₂ reduction among earth-abundant systems with monometallic iron catalysts.

Additional remarks

In addition to the production of CO, a substantial amount of H₂ (TON of 287) was formed in the reduction process with complex 100941.

Content of the published article in detail

The article contains results for the reduction of CO₂ to CO under visible-light catalysis using the iron complex 100941 as a catalyst. The catalytic system performs best (referring to the TON of CO production) in MeCN/TEOA.

Catalyst

100941 100942 100944 100945

Photosensitizer

100940

Investigation

	cat	cat conc [µM]	PS	PS conc [mM]	e-D	e-D conc [M]	solvent A	.	.	additives	.	.	λexc [nm]	.	TON CO	TON CH4	TON H2	.
1.	Molecule:100941	0.1	Molecule:100940	1.0	BIH	0.02	MeCN						420		107		43
2.	Molecule:100941	0.1	Molecule:100940	1.0	BIH	0.02	MeCN						420		109		54
3.	Molecule:100941	0.03	Molecule:100940	0.33	BIH	0.00666	MeCN						420		238		137
4.	Molecule:100941	0.03	Molecule:100940	1.0	BIH	0.02	MeCN						420		314		151
5.	Molecule:100941	0.01	Molecule:100940	1.0	BIH	0.02	MeCN						420		576		287
6.	Molecule:100941	0.1	Molecule:100940	1.0	BIH	0.1	MeCN						420		80		33
7.	Molecule:100941	0.1	Molecule:100940	1.0	BIH	0.1	MeCN			water			420		7.4		6.4
8.	Molecule:100941	0.1	Molecule:100940	1.0	BIH	0.02	MeCN						420		3.2		1.6
9.	Molecule:100941	0.1	Molecule:100940	1.0	BIH	0.02	MeCN						420		80		34
10.	Molecule:100941	0.1	Molecule:100940	1.0	BIH	0.02	MeCN						420		100		43
11.			Molecule:100940	1.0	BIH	0.02	MeCN						420		0		1
12.	Molecule:100941	0.1			BIH	0.02	MeCN						420		0		0
13.	Molecule:100941	0.1	Molecule:100940	1.0	BIH	0.02	MeCN								0		0
14.	Molecule:100941	0.1	Molecule:100940	1.0	BIH	0.02	MeCN						420		0		0
15.	Molecule:100941	0.1	Molecule:100940	1.0	BIH	0.02	MeCN			Hg			420		93		50
16.	Molecule:100941	0.1	Molecule:100940	1.0	BIH	0.02	MeCN						solar simulator		450		348
17.	Molecule:100941	0.01	Molecule:100940	1.0			MeCN						420		6.8	0	0
18.	Molecule:100941	0.01	Molecule:100940	1.0	BIH	0.02	MeCN						420		44	1.16	0
19.	Molecule:100941	0.01	Molecule:100940	1.0			MeCN						420		0	0	0
20.	Molecule:100941	0.01	Molecule:100940	1.0	BIH	0.02	MeCN						420		0	0	0

Investigation-Name: Optimization of CO2 reduction conditionsExport

	cat	cat conc [µM]	PS	PS conc [mM]	e-D	e-D conc [M]	solvent A	.	.	.	λexc [nm]	.	TON CO	TON H2	.
1.	Molecule:100942	0.1	Molecule:100940	1.0	BIH	0.02	MeCN				420		7.8	2
2.	Molecule:100944	0.1	Molecule:100940	1.0	BIH	0.02	MeCN				420		1.1	7.4
3.	Molecule:100945	0.1	Molecule:100940	1.0	BIH	0.02	MeCN				420		0.7	4.9

Investigation-Name: CO2 reduction experiments testing different catalystsExport

Sacrificial electron donor

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

Additives

In this study, control experiments with Hg and without CO₂ were conducted.