Function-Integrated Ru Catalyst for Photochemical CO2 Reduction
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Abstract
Summary
A photochemical reduction of CO2 to CO was shown using the ruthenium catalyst and sensitizer Ru(dppq)(tpy)(MeCN). Turnover numbers (TONs) up to 353 and a selectivity of 97% for CO were reached in dimethylacetamide/water. The experiments were conducted under visible-light irradiation (λ = 420-750 nm) with BIH or TEOA (see section SEDs below) as sacrificial electron donors.
Advances and special progress
The authors describe the at that time first example of a nonsensitized Ru(II) photocatalyst for CO2 reduction. The reported catalyst showed a higher TON and selectivity than previously reportd nonsensitized photocatalysts.
Additional remarks
The product selectivity can be tuned by modification of the basicity of the reaction media. Formic acid can be produced with a selectivity of >99% and a TON of 14 when switching to a dimethylacetamide/TEOA mixture.
Content of the published article in detail
The article contains results for the reduction of CO2 to CO under visible-light catalysis using a ruthenium as a catalyst without the need for an additional sensitizer. The catalytic system performs best (referring to the TON of CO production) in dimethylacetamide/water and can be modified to produce formic acid in dimethylacetamide/TEOA.
Catalyst/Photosensitizer
Investigation
| cat | cat conc [µM] | e-D | e-D conc [M] | solvent A | . | . | additives | λexc [nm] | . | TON CO | . | . | TON H2 | TON HCOOH | . | . | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1. | 0.04 | 0.1 | 420-750 | 58 | 1 | 3 | |||||||||||
| 2. | 0.04 | 0.1 | Argon atmosphere | 420-750 | |||||||||||||
| 3. | 0.1 | 420-750 | |||||||||||||||
| 4. | 0.04 | 420-750 | |||||||||||||||
| 5. | 0.04 | 0.1 | dark | ||||||||||||||
| 6. | 0.04 | 420-750 | 14 |
The catalyst acts also as photosensitizer
| cat | cat conc [µM] | e-D | e-D conc [M] | solvent A | . | . | . | λexc [nm] | . | TON CO | TON H2 | TON HCOOH | . | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1. | 0.02 | 0.1 | Xenon lamp (420 - 750) | 73 | 1 | 8 | ||||||||
| 2. | 0.04 | 0.1 | Xenon lamp (420 - 750) | 58 | 1 | 3 | ||||||||
| 3. | 0.08 | 0.1 | Xenon lamp (420 - 750) | 29 | 2 | |||||||||
| 4. | 0.04 | 0.1 | Xenon lamp (420 - 750) | 42 | 1 | 5 | ||||||||
| 5. | 0.04 | 0.1 | Xenon lamp (420 - 750) | 67 | 1 | 9 | ||||||||
| 6. | 0.04 | 0.1 | Xenon lamp (420 - 750) | 20 | 1 | 6 |
| cat | cat conc [µM] | e-D | e-D conc [M] | solvent A | . | . | additives | . | λexc [nm] | . | TON CO | . | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1. | 0.04 | 0.1 | Xenon lamp (420 - 750) | 4.6 | |||||||||
| 2. | 0.04 | 0.1 | Hg(0) | Xenon lamp (420 - 750) | 4.1 |
| cat | cat conc [µM] | e-D | e-D conc [M] | solvent A | . | . | . | λexc [nm] | . | TON CO | . | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1. | 0.04 | 0.1 | Xenon lamp (420 - 750) | 1.2 | ||||||||
| 2. | 0.04 | 0.1 | Xenon lamp (420 - 750) | 4.6 |
| cat | cat conc [µM] | e-D | e-D conc [M] | solvent A | . | . | . | λexc [nm] | . | TON CO | . | . | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1. | 0.005 | 0.2 | Xenon lamp (420 - 750) | 353 |
Sacrificial electron donor
In this study, the experiments were done with the sacrificial electron donors TEOA (100507) and BIH (100508).
Additives
In this study, the addition of Hg(0) was tested and control experiments under argon atmosphere were conducted.
Investigations
- Concentration and solvent effect (Molecular process, Photocatalytic CO2 conversion experiments)
- Control experiments (Molecular process, Photocatalytic CO2 conversion experiments)
- Hg poisoning (Molecular process, Photocatalytic CO2 conversion experiments)
- Maximum TON (Molecular process, Photocatalytic CO2 conversion experiments)
- Presence of water effect (Molecular process, Photocatalytic CO2 conversion experiments)
