Suppressing Carbon Losses to 5% in Alkaline CO 2 Electrocatalysis Using Gold‐Decorated CuO Nanoneedle Catalysts With Modified Microenvironment
Seyed Parsa Amouzesh, Taha Baghban‐Ronaghi, Moon Gyu Park, Seyed Sepehr Mostafayi, Sina Fazlifard, Karen A. Castaneda, Raju Praveen, Adel Azaribeni, Hamid Arastoopour, Javad Abbasian, Carlo U. Segre, Larry A. Curtiss, Mohammad AsadiABSTRACT
Alkaline CO 2 electrolysis can reach industrially relevant rates, but it typically incurs substantial carbon losses through carbonate formation, limiting conversion efficiency. In this study, we show that combining a gold‐decorated CuO nanoneedle catalyst (N‑CuAu) with dynamic pulsed electrocatalysis and a synthetic electrolyte with tuned bulk hydroxide concentration ([OH − ]‐Bulk) suppresses carbonation while maintaining high overall performance in an alkaline electrolyzer. The integrated strategy reduces carbon losses to 5.7%, while achieving a single‐pass CO 2 conversion of 51% and an overall Faradaic efficiency (FE) of 92% for selective CO 2 reduction. The resulting carbonate formation ratio is about 182‐fold lower than conventional alkaline CO 2 electrolysis and 27 fold lower than state‐of‐the‐art neutral media CO 2 electrolysis. Using complementary in situ and ex situ characterizations, we identify an operative semi‐quantitative local alkalinity ([OH − ]‐Local) of 0.17 mol/Lit that correlates with suppressed carbonate formation and enhanced selectivity toward alcohol products, while confirming catalyst structural stability under dynamic pulsed operation. Together, these results establish hydroxide microenvironment control as a lever to reconcile high‐performance alkaline CO 2 electrolysis with low carbonation losses.