Electrocatalysis of CO2 Reduction in Brush Polymer Ion Gels

The electrochemical characterization of brush polymer ion gels containing embedded small molecule redox-active species is reported. Gels comprising PS-PEO-PS triblock brush polymer, 1-butyl-3-methyl-imidazolium bis(trifluoromethylsulfonyl)imide (BMIm-TFSI), and some combination of ferrocene (Fc), cobaltocenium (CoCp2+), and Re(bpy)(CO)(3)Cl (1) exhibit diffusion-controlled redox processes with diffusion coefficients approximately one-fifth of those observed in neat BMIm-TFSI. Notably, 1 dissolves homogeneously in the interpenetrating matrix domain of the ion gel and displays electrocatalytic CO, reduction to CO in the gel. The catalytic wave exhibits a positive shift versus Fels compared with analogous nonaqueous solvents with a reduction potential 450 mV positive of onset and 90% Faradaic efficiency for CO production. These materials provide a promising and alternative approach to immobilized electrocatalysis, creating numerous opportunities for application in solid-state devices.