A bioinspired molybdenum-copper molecular catalyst for CO 2 electroreduction
Résumé
Non-noble metal molecular catalysts mediating the electrocatalytic reduction of carbon dioxide are still scarce. This work reports the electrochemical reduction of CO 2 to formate catalyzed by the bimetallic complex [(bdt)Mo VI (O)S 2 Cu I CN] 2À (bdt ¼ benzenedithiolate), a mimic of the active site of the Mo-Cu carbon monoxide dehydrogenase enzyme (CODH2). Infrared spectroelectrochemical (IR-SEC) studies coupled with density functional theory (DFT) computations revealed that the complex is only a pre-catalyst, the active catalyst being generated upon reduction in the presence of CO 2. We found that the two-electron reduction of [(bdt)Mo VI (O)S 2 Cu I CN] 2À triggers the transfer of the oxo moiety to CO 2 forming CO 3 2À and the complex [(bdt)Mo IV S 2 Cu I CN] 2À and that a further one-electron reduction is needed to generate the active catalyst. Its protonation yields a reactive Mo V H hydride intermediate which reacts with CO 2 to produce formate. These findings are particularly relevant to the design of catalysts from metal oxo precursors.
Domaines
Chimie
Origine : Publication financée par une institution
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