Multi-electron reduction of CO2 via RuCO2, C(O)OH, CO, CHO, and CH2OH species

Tanaka, Koji; Ooyama, Dai

doi:10.1016/s0010-8545(01)00434-9

Cited by 167 publications

(106 citation statements)

References 73 publications

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“…Further studies will investigate the positioning of the metal centers to form optimized CO 2 capture sites and catalytic species. 13 C NMR, in agreement with the previous reports on the related mononuclear system. …”

Section: Radicals Tpysupporting

confidence: 93%

“…15 As a result, the technologically and energetically viable electrochemical conversion of CO 2 to useful materials remains a challenging task. 3 ; n = 0, 1, and 2) (bpy: 2,2¤-bipyridine), 13 illustrating the manner in which Ru centers could interact with CO 2 molecules. Going further, Meyer et al reported the electrocatalytic reduction of CO 2 to CO using [Ru(tpy)(bpy)(Solv.)]…”

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confidence: 99%

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Electrochemical Carbon Dioxide Reduction Catalyzed by a Dinuclear Ruthenium Complex with a Flexible Bridging Ligand

et al. 2014

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A dinuclear Ru complex, [{Ru(tpy)Cl} 2 (¯-L)](PF 6 ) 2 (1), was synthesized by the reaction of the flexible bridging ligand L (= N,N¤-bis(5-bipyridylhexyl)-cis-1,4-cyclohexanediamine) with [Ru(tpy)Cl 3 ]. The complex contained two [Ru(tpy)(bpy)Cl] + moieties linked by L, and the reaction of 1 with AgNO 3 allowed for isolation of the ligand-exchanged product [{Ru(tpy)-(Solv.)} 2 (¯-L)](PF 6 ) 4 (2). The behavior of 2 as a CO 2 reduction electrocatalyst was investigated in acetonitrile. Under N 2 , two reduction peaks appeared at E p,c = ¹1.08 (tpy/tpy•¹ ) and ¹1.40 V (bpy/bpy•¹ ) vs. NHE. In a saturated CO 2 solution, a further reduction peak, at E p,c = ¹1.60 V, showed significant current enhancement consistent with electrocatalytic CO 2 reduction. The primary product of the CO 2 reduction was CO, and the turnover frequency was calculated to be ca. 1.4 s ¹1 .It is widely accepted that the increasing levels of CO 2 in the atmosphere are adversely affecting the global climate and that new technologies for the fixation and conversion of CO 2 are important goals in mitigating global warming. The electrochemical and photoelectrochemical reduction of CO 2 to provide C1 sources for chemical feedstock and fuels is a key target. CO 2 can be converted, by multielectron paths, to carbon monoxide (2e ¹ ), formate (2e, and methane (8e ¹ ), and the reduction can proceed via a protonassisted multiple-electron-transfer pathway. 15A variety of transition-metal complexes have been shown to be active catalyst precursors for the reduction of CO 2 , but typically at relatively negative potentials or at low reaction rates.612 One of the reasons for this is the stability of the CO 2 molecule, which ensures that a substantial activation energy barrier must be overcome to generate the anion radical. 15 As a result, the technologically and energetically viable electrochemical conversion of CO 2 to useful materials remains a challenging task.OH, CO, CHO, CH 2 OH, CH 3 , and C(O)CH 3 ; n = 0, 1, and 2) (bpy: 2,2¤-bipyridine), 13 illustrating the manner in which Ru centers could interact with CO 2 molecules. Going further, Meyer et al. reported the electrocatalytic reduction of CO 2 to CO using [Ru(tpy)(bpy)(Solv.)] 2+ (tpy: 2,2¤;6¤,2¤¤-terpyridine, Solv.: solvent), with the Ru center mediating the electron transfer from the tpy•¹ and bpy •¹ anion radicals to CO 2 at potentials below ¹1.5 V vs. NHE. 14 Coordination programming is an approach by which molecular design allows for the functionality of molecular species to be tuned though modulation of their coordinative or supramolecular interactions. 15 We hypothesized that dimerization of [Ru(tpy)(bpy)(Solv.)] 2+ units may lead to cooperative catalytic behavior such as multielectron processes, increasing the CO 2 reduction activity of the complex in comparison to the mononuclear species. To that end, we synthesized a dinuclear Ru complexes 1 and 2 and investigated their behavior as CO 2 reduction electrocatalysts (Figure 1).A novel flexible bridging ligand N,N¤-bis(5-bipyridylhexyl)-cis-1,4-...

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Section: Radicals Tpysupporting

confidence: 93%

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confidence: 99%

Electrochemical Carbon Dioxide Reduction Catalyzed by a Dinuclear Ruthenium Complex with a Flexible Bridging Ligand

et al. 2014

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“…To produce highly efficient and selective electrocatalysts, the transitionmetal-based molecular materials are often considered [6][7][8]. The latter systems are capable of driving multi-electron transfers and, in principle, produce highly reduced species.…”

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confidence: 99%

Fabrication of Nanostructured Palladium Within Tridentate Schiff-Base-Ligand Coordination Architecture: Enhancement of Electrocatalytic Activity Toward CO2 Electroreduction

et al. 2014

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There has been growing interest in the electrochemical reduction of carbon dioxide (CO 2 ), a potent greenhouse gas and a contributor to global climate change, and its conversion into useful carbon-based fuels or chemicals [1][2][3][4][5]. Numerous homogeneous and heterogeneous catalytic systems have been proposed to induce the CO 2 reduction and, depending on the reaction conditions (applied potential, choice of buffer, its strength and pH, local CO 2 concentration, or the catalyst used) various products that include carbon monoxide, oxalate, formate, carboxylic acids, formaldehyde, acetone, or methanol, as well as such hydrocarbons as methane, ethane, and ethylene, are typically observed at different ratios. These reaction products are of potential importance to energy technology, food research, medical applications, and fabrication of plastic materials.Given the fact that the CO 2 molecule is very stable, its electroreduction processes are characterized by large overpotentials, and they are not energy efficient. To produce highly efficient and selective electrocatalysts, the transitionmetal-based molecular materials are often considered [6][7][8]. The latter systems are capable of driving multi-electron transfers and, in principle, produce highly reduced species. In reality, such multi-electron charge transfer catalysts tend to effectively induce the two-electron reduction of CO 2 to CO rather than yield highly reduced products in large amounts. Metallic copper electrodes are unique in this respect because they can drive multi-electron transfers. Mechanisms of the successful electrochemical reductions of CO 2 to methane and ethylene can be interpreted in terms of complex processes occurring at copper electrodes [9,10]. It is believed that, during electroreduction, the rate limiting step is the protonation of the adsorbed CO product to form the CHO adsorbate [11]. Significant decrease of the reaction overpotentials can be achieved with the use of the metal complex modified electrodes capable of both mediating electron transfers and stabilizing the reduced products [12].Because reduction of CO 2 can effectively occur by hydrogenation [13], in the present work, we concentrate on such a model catalytic system as nanostructured metallic palladium capable of absorbing reactive hydrogen in addition to the ability to adsorb monoatomic hydrogen at the interface [14][15][16]. Under such conditions, the two-electron reduction of CO 2 typically to CO [12] is favored. When the reaction proceeds on palladium in aqueous KHCO 3 solutions, carbon monoxide together with hydrogen and small amounts of formate are produced [17][18][19]. Further, it has been postulated that CO and COOH adsorbates are expected to be formed at the surfaces of Pd electrodes at −1.0 V (vs. Ag/AgCl) and, subsequently, desorbed at even more negative potentials [20].To produce highly dispersed and stabilized palladium nanoparticles (as for Fig. 1a), we have generated them by electrodeposition (through consecutive potential cycling) from the thin film of...

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“…[4][5][6][7][8][9][10] It has been demonstrated that selectivity of the process depends largely on the activating adsorptive (CO 2 ) phenomena and the affinity of catalytic centers to adsorbed carbon monoxide intermediate. 11 Depending on the strength of adsorption and according to the Sabatier principle, CO may be further protonated or hydrogenated to CHO adsorbate.…”

Section: -3mentioning

confidence: 99%

“…[1][2][3] During recent years, various catalysts, including noble and non-noble transition metals, as well as their numerous coordination compounds, have been considered as catalysts for CO 2 electroreduction. [4][5][6][7][8][9][10] It has been demonstrated that selectivity of the process depends largely on the activating adsorptive (CO 2 ) phenomena and the affinity of catalytic centers to adsorbed carbon monoxide intermediate. 11 Depending on the strength of adsorption and according to the Sabatier principle, CO may be further protonated or hydrogenated to CHO adsorbate.…”

mentioning

confidence: 99%

Carbon Dioxide Electroreduction at Highly Porous Nitrogen and Sulfur Co-Doped Iron-Containing Heterogeneous Carbon Gel

Dembińska

Kiciński

Januszewska

et al. 2017

J. Electrochem. Soc.

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The functionalized carbon nanostructure, nitrogen and sulfur co-doped iron-containing highly porous carbon gel (obtained via carbonization of corresponding organic gel) is considered here as a non-precious metal catalyst for the electroreduction of carbon dioxide in neutral solution (potassium bicarbonate at pH = 6.8). Various electrochemical measurements (performed in distinct modes and under different conditions) have been utilized to comment about the catalyst performance and the reaction mechanism, in particular about the reaction products and the relative contribution from hydrogen evolution. At low overpotentials, the carbon dioxide reduction is favored over the hydrogen evolution reaction. Combination of conventional (stationary) stripping-type and hydrodynamic (rotating ring-disk electrode) voltammetric approaches has been demonstrated to function as an unique electroanalytical tool here. The CO 2 -reduction products can be identified as adsorbates (oxidative stripping voltammetry) or monitored continuously (electrooxidation) at the Pt ring electrode. Finally, the results of both electrochemical diagnostic and parallel gas chromatographic analytical measurements are consistent with the view that, in the examined range of the potentials, CO is the main CO 2 -reduction product. The electrochemical reduction of carbon dioxide (CO 2 ) permits, in principle, selective generation of carbon-based fuels (or syngas) and, indirectly, lowering population of one of green-house gases in the atmosphere. Due to existence of two strong C=O bonds in the CO 2 molecule, its electroreduction requires high overpotentials, and the low reaction efficiency still remains fundamental problem limiting practical applications. 1-3During recent years, various catalysts, including noble and non-noble transition metals, as well as their numerous coordination compounds, have been considered as catalysts for CO 2 electroreduction. [4][5][6][7][8][9][10] It has been demonstrated that selectivity of the process depends largely on the activating adsorptive (CO 2 ) phenomena and the affinity of catalytic centers to adsorbed carbon monoxide intermediate. 11 Depending on the strength of adsorption and according to the Sabatier principle, CO may be further protonated or hydrogenated to CHO adsorbate. This step is often considered as the rate-determining one during the hydrocarbon formation.12 It should be noted here that, for example, copper is capable of successfully catalyzing electroreduction of CO 2 to multicarbon products, 13-15 palladium induces the reaction mainly to CO and H 2 and only small amounts of formate. 2,[16][17][18][19] Another important practical issue is related to the need of lowering costs of catalysts by substituting the noble metals with inexpensive abundant elements. There has been growing interest in catalysts based on nanostructured carbons that include the metal-free Ndoped systems and the metal-containing carbons. [20][21][22][23][24][25][26] For example, the biomimetic centers containing metallic moieties in the vi...

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Multi-electron reduction of CO2 via RuCO2, C(O)OH, CO, CHO, and CH2OH species

Cited by 167 publications

References 73 publications

Electrochemical Carbon Dioxide Reduction Catalyzed by a Dinuclear Ruthenium Complex with a Flexible Bridging Ligand

Electrochemical Carbon Dioxide Reduction Catalyzed by a Dinuclear Ruthenium Complex with a Flexible Bridging Ligand

Fabrication of Nanostructured Palladium Within Tridentate Schiff-Base-Ligand Coordination Architecture: Enhancement of Electrocatalytic Activity Toward CO2 Electroreduction

Carbon Dioxide Electroreduction at Highly Porous Nitrogen and Sulfur Co-Doped Iron-Containing Heterogeneous Carbon Gel

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