Function-Integrated Ru Catalyst for Photochemical CO2 Reduction
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Abstract[edit | edit source]
Summary[edit | edit source]
A photochemical reduction of CO2 to CO was shown using the ruthenium catalyst and sensitizer Ru(dppq)(tpy)(MeCN) (100695). 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[edit | edit source]
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 reported nonsensitized photocatalysts.
Additional remarks[edit | edit source]
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[edit | edit source]
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[edit | edit source]
Investigation[edit | edit source]
| cat | cat conc [µM] | e-D | e-D conc [M] | solvent A | . | . | additives | λexc [nm] | . | TON CO | . | . | TON H2 | TON HCOOH | . | . | . | ||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| (edit) | 1. | Ru(dppq)(tpy)(MeCN) | 40 | BIH | 0.1 | DMA | 420-750 | 58 | 1 | 3 | |||||||||
| (edit) | 2. | Ru(dppq)(tpy)(MeCN) | 40 | BIH | 0.1 | DMA | Argon atmosphere | 420-750 | |||||||||||
| (edit) | 3. | 40 | BIH | 0.1 | DMA | 420-750 | |||||||||||||
| (edit) | 4. | Ru(dppq)(tpy)(MeCN) | 40 | DMA | 420-750 | ||||||||||||||
| (edit) | 5. | Ru(dppq)(tpy)(MeCN) | 40 | BIH | 0.1 | DMA | dark | ||||||||||||
| (edit) | 6. | Ru(dppq)(tpy)(MeCN) | 40 | TEOA | DMA | 420-750 | 14 |
Investigation-Name: Control experimentsThe 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 | . | . | ||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| (edit) | 1. | Ru(dppq)(tpy)(MeCN) | 20 | BIH | 0.1 | DMA | Xenon lamp (420 - 750) | 73 | 1 | 8 | ||||||
| (edit) | 2. | Ru(dppq)(tpy)(MeCN) | 40 | BIH | 0.1 | DMA | Xenon lamp (420 - 750) | 58 | 1 | 3 | ||||||
| (edit) | 3. | Ru(dppq)(tpy)(MeCN) | 80 | BIH | 0.1 | DMA | Xenon lamp (420 - 750) | 29 | 2 | |||||||
| (edit) | 4. | Ru(dppq)(tpy)(MeCN) | 40 | BIH | 0.1 | MeCN | Xenon lamp (420 - 750) | 42 | 1 | 5 | ||||||
| (edit) | 5. | Ru(dppq)(tpy)(MeCN) | 40 | BIH | 0.1 | DMA | Xenon lamp (420 - 750) | 67 | 1 | 9 | ||||||
| (edit) | 6. | Ru(dppq)(tpy)(MeCN) | 40 | BIH | 0.1 | DMA | Xenon lamp (420 - 750) | 20 | 1 | 6 |
Investigation-Name: Concentration and solvent effect
| cat | cat conc [µM] | e-D | e-D conc [M] | solvent A | . | . | additives | . | λexc [nm] | . | TON CO | . | . | ||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| (edit) | 1. | Ru(dppq)(tpy)(MeCN) | 40 | BIH | 0.1 | DMA | Xenon lamp (420 - 750) | 4.6 | |||||||
| (edit) | 2. | Ru(dppq)(tpy)(MeCN) | 40 | BIH | 0.1 | DMA | Hg(0) | Xenon lamp (420 - 750) | 4.1 |
Investigation-Name: Hg poisoning
| cat | cat conc [µM] | e-D | e-D conc [M] | solvent A | . | . | . | λexc [nm] | . | TON CO | . | . | ||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| (edit) | 1. | Ru(dppq)(tpy)(MeCN) | 40 | BIH | 0.1 | DMA | Xenon lamp (420 - 750) | 1.2 | ||||||
| (edit) | 2. | Ru(dppq)(tpy)(MeCN) | 40 | BIH | 0.1 | DMA | Xenon lamp (420 - 750) | 4.6 |
Investigation-Name: Presence of water effect
| cat | cat conc [µM] | e-D | e-D conc [M] | solvent A | . | . | . | λexc [nm] | . | TON CO | . | . | . | ||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| (edit) | 1. | Ru(dppq)(tpy)(MeCN) | 5 | BIH | 0.2 | DMA | Xenon lamp (420 - 750) | 353 |
Investigation-Name: Maximum TON
Sacrificial electron donor[edit | edit source]
In this study, the experiments were done with the sacrificial electron donors TEOA (100507) and BIH (100508).
Additives[edit | edit source]
In this study, the addition of Hg(0) was tested and control experiments under argon atmosphere were conducted.
Tags: CO2 photoreduction, visible-light photocatalysis, ruthenium catalyst, Ru(dppq)(tpy)(MeCN), photosensitizer-free system, homogeneous catalysis, CO evolution, formic acid production, high turnover number, high selectivity, sacrificial electron donors, BIH, TEOA, dimethylacetamide solvent, water co-solvent, photoredox chemistry |
Investigations
- Control experiments (Molecular process, Photocatalytic CO2 conversion experiments)
- Concentration and solvent effect (Molecular process, Photocatalytic CO2 conversion experiments)
- Hg poisoning (Molecular process, Photocatalytic CO2 conversion experiments)
- Presence of water effect (Molecular process, Photocatalytic CO2 conversion experiments)
- Maximum TON (Molecular process, Photocatalytic CO2 conversion experiments)
