Report

A Local Proton Source Enhances CO2 Electroreduction to CO by a Molecular Fe Catalyst

See allHide authors and affiliations

Science  05 Oct 2012:
Vol. 338, Issue 6103, pp. 90-94
DOI: 10.1126/science.1224581

You are currently viewing the abstract.

View Full Text

Lending a Hand to CO2 Reduction

Although plants and microbes have been reducing CO2 with ease for millennia, people still find it extremely challenging. A cost-effective synthetic scheme for transforming CO2 into fuels and commodity chemicals would be a double boon, lowering atmospheric concentration of the greenhouse gas while supplementing (and perhaps ultimately replacing) dwindling petroleum feedstocks. Toward this end, Costentin et al. (p. 90) show that an iron catalyst for the electrochemical reduction of CO2 to CO gets an efficiency boost from phenol substituents appended to the ligand framework.

Abstract

Electrochemical conversion of carbon dioxide (CO2) to carbon monoxide (CO) is a potentially useful step in the desirable transformation of the greenhouse gas to fuels and commodity chemicals. We have found that modification of iron tetraphenylporphyrin through the introduction of phenolic groups in all ortho and ortho′ positions of the phenyl groups considerably speeds up catalysis of this reaction by the electrogenerated iron(0) complex. The catalyst, which uses one of the most earth-abundant metals, manifests a CO faradaic yield above 90% through 50 million turnovers over 4 hours of electrolysis at low overpotential (0.465 volt), with no observed degradation. The basis for the enhanced activity appears to be the high local concentration of protons associated with the phenolic hydroxyl substituents.

View Full Text