Stable dual metal oxide matrix for tuning selectivity in acidic electrochemical carbon dioxide reduction
Ziling Zhang, Thành Trần‐Phú, Jodie A. Yuwono, Zhipeng Ma, Yuwei Yang, Josh Leverett, Rosalie K. Hocking, Bernt Johannessen, Priyank V. Kumar, Rose Amal, Rahman Daiyan
Abstract
The acidic electrochemical CO 2 reduction reaction (CO 2 RR) holds promise for achieving a carbon-neutral future and can promote efficient CO 2 utilization by attenuating the carbonate/bicarbonate formation reaction. However, catalyst degradation in strong acids and the competing hydrogen evolution reaction (HER) often result in short catalyst lifetime and poor product selectivity. Herein, this study introduces a strategy to stabilize copper oxide (CuO x ) catalysts for acidic CO 2 reduction (CO 2 RR) by incorporating bismuth oxide (BiO x ) and achieved a maximum formic acid Faradaic efficiency (FE HCOOH ) of 97 ± 1 % at −2.7 V vs. RHE and maintaining over 90 % FE for more than 20 h. In situ XAS, SR-FTIR and density functional theory (DFT) calculations show that the catalyst can inhibit *H adsorption and promote selective CO 2 conversion to HCOOH via the HCOO* pathway. Further electrolyte anion modulation achieves ethanol and acetone production at Faradaic efficiencies of 17 % and 16 % in phosphoric and perchloric acid, respectively. In situ analyses reveal that distinct anion adsorption influence key intermediates, such as *CO, leading to shifts in C₂ ⁺ product distributions. This work offers insights into designing acid-stable electrocatalysts for CO 2 RR and highlights the potential of electrolyte modification to tailor product selectivity. • Stabilized Cu + in acidic CO 2 RR using dual CuO x /BiO x metal oxide matrix. • Extended catalyst stability using facile and scalable FSP synthesis. • Achieved remarkable formic acid selectivity (FE = 97 %) under acidic conditions. • Tuned C 2+ product distributions via distinct anion adsorption in electrolytes.