A polymerized ionic liquid functionalized cathode catalyst support for a proton exchange membrane CO2 conversion cell

Abstract

This study aims at the efficient conversion of CO₂ to formic acid using a proton exchange membrane cell by selective functionalization of a cathode catalyst support. We chose polymerized ionic liquid (PIL) as the surface functional moiety, since CO₂ has good solubility in it. A multiwalled carbon nanotube (MWNTs) surface was functionalized with PIL and used as a cathode catalyst support. This novel catalyst support shows extremely good affinity towards CO₂ and facilitates better dispersion of catalyst nanoparticles. Catalytic nanoparticles were decorated over the catalyst supports by a microwave assisted polyol reduction method, which gives better dispersion of finer particles on PIL functionalized MWNTs compared to pure MWNTs. The protonation of CO₂ to formic acid has been studied in a polymer electrolyte membrane (PEM) CO₂ conversion cell with synthesized catalysts. The cells were tested under continuous and discontinuous CO₂ supply, where PIL functionalized MWNTs show a better formic acid formation rate than the pure support under identical experimental conditions, due to the improved interaction between the catalyst support and CO₂ molecules.