Task-specific functionalization of graphene for use as a cathode catalyst support for carbon dioxide conversion

Abstract

This study describes the potential advantages of task-specific functionalization of graphene for carbon dioxide capture and conversion. An ionic liquid was employed as a functional moiety on a graphene catalyst support since it shows reversible interactions with CO₂ molecules. In this study, graphene was synthesized by a hydrogen-assisted low-temperature-exfoliation method and functionalized using a polymerized ionic liquid (PIL). Adsorption analysis shows that PIL functionalization improves the CO₂ adsorption capacity of graphene significantly. Catalytic nanoparticles were dispersed over the catalyst supports by a microwave assisted polyol reduction method and the catalysts were employed as the cathode catalyst in a polymer electrolyte membrane (PEM) CO₂ conversion cell. The cell hydrogenates CO₂ into formic acid at the cathode, which was quantified by spectrophotometry. The PIL functionalized support shows a higher formic acid formation rate compared to a pure support under similar experimental conditions since PIL functionalization improves the interactions between the catalyst support and the CO₂ molecules. The cells were tested with discontinuous and continuous CO₂ supplies.