Exchange Coupling Determines Metal-Dependent Efficiency for Iron- and Cobalt-Catalyzed Photochemical CO2 Reduction
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Abstract
Summary
A photochemical reduction of CO2 to CO was shown using an Fe2+ and Co2+ complex as catalysts in combination with different photosensitizers. The authors examined the efficiency for photocatalytic CO2RR pending on metal−ligand exchange coupling as an example of charge delocalization. The iron complex 100968 and cobalt complexes100969, both bearing the redox-active ligand tpyPY2Me were tested in comparison. It was found that the two-electron reduction of the Co(tpyPY2Me)]2+ catalyst 100969 occurs at potentials 770 mV more negative than the Fe(tpyPY2Me)]2+ analogue100968 due to maximizing the exchange coupling in the latter compound.
Advances and special progress
Additional remarks
Content of the published article in detail
Catalysts tested in this study
Photosensitizer
Ru(bpy)3
3,6-Diamino-10-methylacridinium
100971
Ir(ppy)3
Investigation
General details for the experimental setup: Conducted inside a 25 mL borosilicate culture tube with a stir bar, a rubber septum, and an aluminum crimped top. The reaction vessel contained 5 mL of CH3CN, 2 μM of the catalyst, 200 μM of the photosensitizer, 100 mM BIH (112 mg), and 1 M phenol (470 mg). The reaction tubes were sparged with CO2 for 10 min, followed by injection of a gaseous internal standard (0.1 mL of C2H6). The reactions were placed on a stirplate 13 cm from two Kessil blue LED lamps (440 nm) for 15 or 30 min at a time and maintained at ambient temperature using a fan. Analysis of the headspace by Gas Chromatography (GC).
| cat | cat conc [µM] | PS | PS conc [mM] | e-D | e-D conc [M] | . | . | solvent A | additives | . | . | TON CO | TON H2 | . | . | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1. | 2 | 0.2 | 0.1 | 15520 | 86 | |||||||||||
| 2. | 0.2 | 0.2 | 0.1 | 30349 | 1013 | |||||||||||
| 3. | 0.2 | 0.1 | 43 | 52 | ||||||||||||
| 4. | 2 | 0.1 | 112 | 0 | ||||||||||||
| 5. | 2 | 0.2 | 150 | 0 | ||||||||||||
| 6. | 2 | 0.2 | 0.1 | 6 | 0 | |||||||||||
| 7. | 2 | 0.2 | 0.1 | Ar | 0 | 222 | ||||||||||
| 8. | 2 | 0.2 | 0.1 | 12749 | 163 | |||||||||||
| 9. | 0.2 | 0.2 | 0.1 | 28712 | 6527 | |||||||||||
| 10. | 2 | 0.2 | 0.1 | 18502 | 141 | |||||||||||
| 11. | 2 | 0.2 | 0.1 | 6710 | 0 |
The values in Table 2 include TOF numbers given in TON/h
| cat | cat conc [µM] | PS | PS conc [mM] | e-D | e-D conc [M] | . | . | solvent A | . | . | . | . | . | . | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1. | 2 | 0.2 | 0.1 | ||||||||||||
| 2. | 2 | 0.2 | 0.1 | ||||||||||||
| 3. | 2 | 0.2 | 0.05 | ||||||||||||
| 4. | 2 | 0.2 | 0.05 | ||||||||||||
| 5. | 2 | 0.2 | 0.05 | ||||||||||||
| 6. | 2 | 0.2 | 0.05 | ||||||||||||
| 7. | 2 | 0.2 | 0.05 | ||||||||||||
| 8. | 2 | 0.2 | 0.05 | ||||||||||||
| 9. | 2 | 0.2 | 0.05 |
Further Information
The results for the catalytic activity of the Co2+ compound100969 in Table 2 were gained from the Supporting Information.
Sacrificial electron donor
In this study, the experiments were done with the sacrificial electron donor BIH (100508).
Additives
Different sources of protons were used, e.g. PhOH, TFE and
4-CHLOROPHENOL
Investigations
- CO2+ results from SI (Molecular process, Photocatalytic CO2 conversion experiments)
- CO2 Reduction under diverse conditions with diverse sensitizers (Molecular process, Photocatalytic CO2 conversion experiments)
- Iron-Catalyzed Photochemical CO2 Reduction under diverse conditions (Molecular process, Photocatalytic CO2 conversion experiments)
- Iron-Catalyzed Photochemical CO2 Reduction under diverse conditions error (Molecular process, Photocatalytic CO2 conversion experiments)
- Results Co2+ experiments taken from SI (Molecular process, Photocatalytic CO2 conversion experiments)
- Results obtained in a reaction with CO2+ catalyst (Assay, Cyclic Voltammetry experiments, Pages using duplicate arguments in template calls)
- Results obtained with Co2+ catalyst (Molecular process, Photocatalytic CO2 conversion experiments)
- Table 2 Co catalyst testing (Molecular process, Photocatalytic CO2 conversion experiments)
- Table 2 Conversion with Co catalyst (Molecular process, Photocatalytic CO2 conversion experiments)
- Table 2 conversion with Co catalyst (Molecular process, Photocatalytic CO2 conversion experiments)
- results CO2+ experiments (Molecular process, Photocatalytic CO2 conversion experiments)
- testtest2 (Molecular process, Photocatalytic CO2 conversion experiments)
