12 research outputs found
Electro-Oxidation of Nitrite Using an Oxidized Glassy Carbon Electrode as Amperometric Sensor
Oxidative Coupling and Hydroxylation of Phenol over Transition Metal and Acidic Zeolites: Insights into Catalyst Function
Properties and catalytic performance in phenol hydroxylation of iron on zeolite beta prepared by different methods
Electrocatalytic reduction of carbon dioxide to carbon monoxide and methane at an immobilized cobalt protoporphyrin
The electrochemical conversion of carbon dioxide and water into useful products is a major challenge in facilitating a closed carbon cycle. Here we report a cobalt protoporphyrin immobilized on a pyrolytic graphite electrode that reduces carbon dioxide in an aqueous acidic solution at relatively low overpotential (0.5 V), with an efficiency and selectivity comparable to the best porphyrin-based electrocatalyst in the literature. While carbon monoxide is the main reduction product, we also observe methane as by-product. The results of our detailed pH-dependent studies are explained consistently by a mechanism in which carbon dioxide is activated by the cobalt protoporphyrin through the stabilization of a radical intermediate, which acts as Bronsted base. The basic character of this intermediate explains how the carbon dioxide reduction circumvents a concerted proton-electron transfer mechanism, in contrast to hydrogen evolution. Our results and their mechanistic interpretations suggest strategies for designing improved catalysts