New strategy boosting carbon dioxide reduction to carbon monoxide
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NEW STRATEGY BOOSTING CARBON DIOXIDE REDUCTION TO CARBON MONOXIDE
view moreCREDIT: DICP
Classical strong metal-support interaction (SMSI) describes that reducible oxide migrates to the surface metal nanoparticles (NPs) to obtain metal@oxide encapsulation structure during high-temperature H2 thermal treatment, resulting in high selectivity and stability.
However, the encapsulation structure inhibits the adsorption and dissociation of reactant molecular (e.g., H2) over metal, leading to low activity, especially for the hydrogenation reaction.
Recently, a research group led by Prof. LIU Yuefeng from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences (CAS) has proposed a new migration strategy, in which the TiO2 selectively migrates to second oxide support rather than the surface of metal NPs in Ru/(TiOx)MnO catalysts, boosting the CO2 reduction to CO via reverse water-gas shift reaction.
This study was published in Nature Catalysis on Oct. 9.
The researchers achieved controlled migration by utilizing the strong interaction between TiO2 and MnO in Ru/(TiOx)MnO catalysts during H2 thermal treatment, and TiO2 spontaneously re-dispersed on the MnO surface, avoiding the formation of TiOx shell on Ru NPs for the ternary catalyst (Ru/TiOx/MnO).
Meanwhile, high-density TiOx/MnO interfaces generated during the process, acting as a highly efficient H transportation channel with low barrier, and resulting in enhanced H-spillover for the migration of activated H species from metal Ru to support for consequent reaction.
The Ru/TiOx/MnO catalyst showed 3.3-fold catalytic activity for CO2 reduction to CO compared with Ru/MnO catalyst. In addition, the Ti/Mn support preparation was not sensitive to the crystalline structure and grain size of TiO2 NPs. Even the mechanical mixing of Ru/TiO2 and Ru/MnOx enhanced the activity.
Moreover, they verified that the synergistic effect of TiO2 and MnO didn't alter the catalytic intrinsic performance, and efficient H transport provided a large number of active sites (hydroxyl groups) for the reaction process.
"Our study provides references for the design of novel selective hydrogenation catalysts via the in-situ creation of oxide-oxide interfaces acting as hydrogen species transport channels," said Prof. LIU.
JOURNAL
Nature Catalysis
METHOD OF RESEARCH
Commentary/editorial
SUBJECT OF RESEARCH
Not applicable
ARTICLE TITLE
Generation of oxide surface patches promoting H-spillover in Ru/(TiOx)MnO catalysts enables CO2 reduction to CO
Dinuclear ruthenium complex as a photocatalyst for selective CO2 reduction to CO
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ORTEP DRAWING OF THE CRYSTAL STRUCTURE OF DINUCLEAR RUTHENIUM COMPLEX
view moreCREDIT: UNIVERSITY OF TSUKUBA
Tsukuba, Japan—Similar to the process of photosynthesis in plants, the conversion and storage of solar energy into chemical energy hold significant promise for addressing critical energy and environmental challenges, including the depletion of fossil fuels and threat of global warming. One promising avenue in this pursuit involves harnessing light energy to convert CO2 into value-added chemicals.
In this study, the researchers harnessed the potent photocatalytic properties of a ruthenium (Ru) dinuclear complex with self-photosensitizing capabilities to achieve a remarkably efficient CO2 reduction reaction. This process yields a remarkably high selectivity for carbon monoxide (CO). When a dimethylacetamide/H₂O mixture containing the Ru dinuclear complex as a photocatalyst and a sacrificial reducing agent was exposed to light with a central wavelength of 450 nm in 1 atm CO2 atmosphere for 10 h, all the sacrificial reducing agent was consumed, and the substrate CO2 was converted into CO with a selectivity exceeding 99%. The maximum quantum yield at 450 nm was determined to be 19.7%. Furthermore, even when the initial CO2 concentration in the gas phase was reduced to 1.5%, the photocatalytic CO2 reduction by the Ru complex proceeded with remarkable efficiency, indicating that nearly all the introduced CO2 could be converted into CO.
In this newly developed Ru dinuclear complex, the two Ru complex moieties engage in photosensitization, enhancing the stability of the complex catalyst under reaction conditions. This enhanced stability is attributed to the extraordinarily strong chelating effect of the ligand employed. The researchers have future plans for further enhancing the catalytic activity to create a reaction system capable of efficiently driving the CO2 reduction process, even at a lower CO2 concentration equivalent to that of the Earth's atmosphere, which is approximately 420 ppm.
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This work was supported by Grants-in-Aid (nos. 21K18973 and 21H01947) from the Japan Society of Promotion of Science (JSPS, MEXT) and a Grant-in-Aid for Transformative Research Areas (A) Green Catalysis Science for Renovating Transformation of Carbon-Based Resources (Green Catalysis Science) (JSPS KAKENHI grant no. JP23H04902).
Original Paper
Title of original paper:
Self-Photosensitizing Dinuclear Ruthenium Catalyst for CO2 Reduction to CO
Journal:
Journal of the American Chemical Society
Correspondence
Professor KOJIMA, Takahiko
Department of Chemistry, Institute of Pure and Applied Sciences, University of Tsukuba
Related Link
Institute of Pure and Applied Sciences
JOURNAL
Journal of the American Chemical Society
ARTICLE TITLE
Self-Photosensitizing Dinuclear Ruthenium Catalyst for CO2 Reduction to CO
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