Iron-catalyzed photoreduction of carbon dioxide to synthesis gas

Abstract

Photocatalytic processes to convert CO₂ to useful products including CO and HCOOH are of particular interest as a means to harvest the power of the sun for sustainable energy applications. Herein, we report the photocatalytic reduction of CO₂ using iron catalysts and visible light generating varying ratios of synthesis gas. In most cases, either a 1 : 1 CO : H₂ ratio was observed or the selectivity was skewed slightly towards CO with combined TONs reaching nearly 100. Operando FTIR studies revealed the favourable activity of FeBr₂ as an iron precursor to generate the catalytically active species Fe(CO)₃bpy. The Fe(CO)₃bpy complex was then synthesized and successfully applied as a catalyst at various loadings providing almost 300 total TONs for syngas formation. This represents the highest activity reported thus far for an iron-based system in photocatalytic CO₂ reduction.