Electrocatalytic Reduction of CO₂ to CO and CH₄ by Co–N–C Catalyst and Ni co-catalyst with PEM Reactor

Abstract

Utilization of renewable energy has been proposed for solution of the Global Warming. Electroreduction of CO₂ into valuable chemicals using renewable electricity is a promising technology. Electroreduction of CO₂ to CO and CH₄ was studied using the polymer-electrolyte-membrane (PEM) gas cell. The electrocatalyst prepared by partial pyrolysis of Co-4,4’-dimethyl-2,2’-bipyridine supported on KEJENBLACK at 673 K (Co-dmbpy/KB(673K)) has been found for selective reduction of CO₂ to CO. Screening of co-catalysts to promote formation of CH₄ during the CO₂ reduction by the Co-dmbpy/KB(673K) cathode was conducted in this work. An effective Ni/KB co-catalyst prepared by H₂ reduction at 673 K was found. Suitable preparation conditions and methods of the cathode and effects of cathode potentials on the CO₂ reduction to CO and CH₄ were studied. The reaction path for the formation of CH₄ in the CO₂ reduction was studied and the successive reduction of CO₂ to CO on the Co-dmbpy/KB(673K) catalyst and CO to CH₄ on the Ni/KB(673K) co-catalyst was determined.

Schematic diagram of the PEM electrolysis cell for CO₂ reduction.