Carbon - iron electro-catalysts for CO2 reduction. The role of the iron particle size

Abstract

Different types of carbon-iron electro-catalysts have been prepared, exhaustively characterized, and tested as cathodes for the electro-catalytic reduction of CO2 at atmospheric pressure. Commercial iron and graphite sheets have also been tested as cathodes for comparison.All these electro-catalysts promoted the formation of C1 to C4 hydrocarbons showing a high selectivity to C3 hydrocarbons within this group of compounds. The iron particle size seems to be a very important parameter involved in the hydrocarbon formation. A linear correlation between mean iron particle sizes determined by XRD and the faradaic efficiency of the materials has been found: the smaller the iron particle size, the higher the faradaic efficiency. Iron nano-particles smaller than 4 nm increased significantly the formation of hydrocarbons.