Electrocatalytic reduction of carbon dioxide on SnO₂/MWCNT in aqueous electrolyte solution

This communication reports the activity of SnO₂/MWCNT (multi-walled carbon nanotubes) electrocatalysts for CO₂ reduction in an aqueous electrolyte solution using two compartment electrochemical cell. The effect of metal loading of the powdered catalysts (working electrode) on the reduction capabilities of CO₂ are studied, under ambient pressure and room temperature conditions. Electrochemical techniques such as linear sweep voltammetry and chronoamperometry are employed to get the current response (current density) for CO₂ reduction at different applied potentials. Current densities (C.D.) and the faradaic efficiencies (F.E.) of the products are the key performance indicators for any electrochemical process. The higher current densities and faradaic efficiencies for CO₂ reduction are obtained with the optimum SnO₂ content (20% by weight) on the high surface area MWCNT support. The 20% SnO₂/MWCNT catalyst shows remarkable activity for CO₂ conversion to formate with F.E. of c.a. 27.2% at a potential of -1.7V vs. SCE (Saturated Calomel Electrode). The higher activity is attributed to the uniform dispersion and more availability of active sites for CO₂ reduction.