Selective Electrochemical CO2 Reduction to Ethylene and Multi-carbon Products on Oxide-derived Porous CuO Micro-cages

Abstract

The electrochemical reduction of CO₂ (CO₂RR) presents a dual benefit: it helps mitigate environmental pollution while producing valuable multi-carbon (C₂₊) chemicals and storing renewable energy in chemical fuels. However, there is an urgent need for efficient electrocatalysts that can selectively increase the production of ethylene and C₂₊ products for the wide-scale implementation of CO₂RR. Herein, we have facilely synthesized porous micro-caged oxide-derived copper oxide (OD-Cu MC) using a one-pot hydrothermal approach followed by air-annealing at 350 °C. The resulting electrocatalyst exhibited excellent performance for ethylene (C₂H₄) production, achieving a faradaic efficiency (FE) of 44.8 % for C₂H₄ and cumulative FE of 73.1 % for C₂₊ products at current density (I_D) of 300 mA cm⁻². At an I_D of 400 mA cm⁻², OD-Cu MC demonstrated a turnover frequency (TOF) of 0.012 s⁻¹ for ethylene, which is 7.8 times higher than the TOF observed for commercially available copper oxide (CuO-CM). Moreover, at an I_D of 300 mA cm⁻², OD-Cu MC achieved a single-pass CO₂ conversion (SPCC) of 35.2 % and a half-cell energy efficiency of 15.6 % for C₂₊ products. The catalyst also showed good stability, maintaining its performance for over 4 h at an I_D of 200 mA cm⁻². This straightforward synthesis approach opens new avenues for enhancing C₂₊ product selectivity in CO₂RR.