Surface modification of metallic Cu by conventional oxidation and an alternative method of oxidation using flame annealing and its influence on electrochemical reduction (ECR) of CO2 are reported in this study. The ECR of CO2 in aqueous KCl electrolyte yielded methane, ethane, ethylene, and hydrogen as the major products. The faradaic efficiency of ethane obtained at -1.2 V vs NHE for flame-annealed Cu (34 %) was comparable to the conventionally oxidised Cu (40 %), while bare Cu yielded methane (10 %). The metal-metal oxide interface on the electrode aids in the formation of C-2-based products. Flame annealing can be regarded as an alternative electrode preparation method for C-2 product formation, with its merits in high specific surface area, self-rejuvenating mode on deactivation and ease of preparation.
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