Electrocatalytic CO₂ Reduction by [Re(CO)₃Cl(3-(pyridin-2-yl)-5-phenyl-1,2,4-triazole)] and [Re(CO)₃Cl(3-(2-pyridyl)-1,2,4-triazole)]

Abstract

The exploration of novel electrocatalysts for CO 2 reduction is necessary to overcome global warming and the depletion of fossil fuels. In the current study, the electrocatalytic CO 2 reduction of [Re(CO) 3 Cl( N - N )], where N - N represents 3-(2-pyridyl)-1,2,4-triazole (Hpy), 3-(pyridin-2-yl)-5-phenyl-l,2,4-triazole (Hph), and 2,2′-bipyridine-4,4′ dicarboxylic acidic (bpy-COOH) ligands, was investigated. In CO 2 -saturated electrolytes, cyclic voltammograms showed an enhancement of the current at the second reduction wave for all complexes. In the presence of triethanolamine (TEOA), the currents of Re(Hpy), Re(Hph), and Re(bpy-COOH) enhanced significantly by approximately 4-, 2-, and 5-fold at peak potentials of −1.60, −150, and −1.69 V Ag/Ag+ , respectively (in comparison to without TEOA). The reduction potential of Re(Hph) was less negative than those of Re(Hpy) and Re(COOH), which was suggested to cause its least efficiency for CO 2 reduction. Chronoamperometry measurements showed the stability of the cathodic current at the second reduction wave for at least 300 s, and Re(COOH) was the most stable in the CO 2 -catalyzed reduction. The appearance and disappearance of the absorption band in the UV/vis spectra indicated the reaction of the catalyst with molecular CO 2 and its conversion to new species, which were proposed to be Re- DMF + and Re- TEOA and were supposed to react with CO 2 molecules. The CO 2 molecules were claimed to be captured and inserted into the oxygen bond of Re- TEOA , resulting in the enhancement of the CO 2 reduction efficiency. The results indicate a new way of using these complexes in electrocatalytic CO 2 reduction.

Ruthenium–rhenium and ruthenium–palladium supramolecular photocatalysts for photoelectrocatalytic CO2 and H+ reduction

“…S40 & S41‡). The observed current increase for Re(Hbpt)(CO) 3 Cl matches well with the value observed for the similar Re(Hph)(CO) 3 Cl (3.58) complex, which was previously reported for electrocatalytic CO 2 reduction by Nguyen et al 92 The fairly small difference in catalytic activity between the Re(bpt)(CO) 3 Cl fragment and the supramolecular assembly PC1 is consistent with the limited influence of the Ru fragment on the Re catalytic centre as observed for the analogous supramolecular assembly utilising the bpt bridging ligand but with ester rather than acid groups on the peripheral bpy ligands. 80…”

Constructing a rhenium complex supported on g-C3N4 for efficient visible-light-driven photoreduction of CO2 to CO via a novel Z-scheme heterojunction

“…To clarify the mechanism of PCO2R of the hybrid system, the reduction potential of Re(bpy-COOH) and the energy level of g-C 3 N 4 need to be mentioned. Re(bpy-COOH) is a good electrocatalyst for CO 2 reduction, with LUMO potential 39 at −1.94 vs. NHE (or one-electron reduction potential, E red = −1.69 V vs. Ag/AgNO 3 ) and the HOMO potential for absorbing visible light is approximately 0.75 eV vs. NHE (MLCT band, see the UV/Vis absorbance spectrum of Re(bpy-COOH) in Fig. S3†).…”

“…The Re(CO) 3 (bpy-COOH)Cl complex was synthesized following a previous report. 39 The complex was synthesized by reuxing the mixture of [Re(CO) 5 Cl] (200 mg, 0.55 mM) and 0.55 mM bpy-COOH ligand in 50 mL toluene for 6 hours under an Ar atmosphere to give a red-orange solution ([Re(CO) 3 Cl(2,2 ′ -bipyridine-4,4 ′ dicarboxylic acid)] Re(bpy-COOH)). Re(bpy-COOH) was recrystallized from acetone-hexane.…”

Co-sensitization of Copper Indium Gallium Disulfide and Indium Sulfide on Zinc Oxide Nanostructures: Effect of Morphology in Electrochemical Carbon Dioxide Reduction

“…Converting carbon dioxide (CO 2 ) into valuable chemicals and fuels has made an impact on reducing our carbon footprint. − However, the high stability of CO 2 for conversion into different chemicals restricts the application. Therefore, the research community has focused on developing materials and systems for efficient CO 2 conversion by reducing the high activation energy of CO 2 . − It is possible to achieve CO 2 reduction via various routes, including photocatalytic and electrochemical conversion. − In this way, besides decreasing carbon emissions, value-added chemicals, such as methanol, hydrogen, formic acid, and syngas, can be produced. − Among these chemicals, formic acid stands out as an alternative to fossil fuels due to its advantages, such as being an energy-intensive material, having a high volumetric hydrogen density, and having enormous potential as an effective hydrogen storage vector . Typically, the most important factor in producing different types of chemicals, from formic acid to carbon monoxide and multicarbon hydrocarbons and oxygenates, is the selectivity of the used catalyst.…”