(449h) Enhance Selectivity Towards Products By Coating Oxide Layer on Bi-Metallic Copper Catalyst

Electrochemical reduction of CO₂ (ECR) powered by renewable energy sources have emerged as a powerful technology to fight a global battle against climate change. The present work focuses on different strategies for synthesizing bi-metallic (Cu-M) catalyst, where M is the secondary metal such as Ag or Au or Zn. The composition of these secondary metals varies from 1-20%. Also, the studies are performed for bi-metallic copper oxide (Cu₂O-M) as catalyst. A physical vapor deposition technique is employed for catalyst synthesis. It is well known that Cu based catalysts undergo dynamic structural and morphological changes under ECR operating conditions which reduces lifetime of the catalysts by removing the oxide layer. To stabilize the oxide layer on catalyst, asymmetric reduction and oxidation pulses are employed for catalyst regeneration under controlled microenvironments. The experimental results clearly demonstrate that presence of secondary metal tailor selectivity towards C2 products. Also, there exists an optimum concentration of secondary metal beyond which it leads to lower selectivity towards C2 products. Further, the selectivity varies in presence or absence of copper oxides (Cu₂O-M). Amongst all, Cu-Ag bimetal shows higher selectivity (>40%) towards C2 products. However, the presence of oxides in case of Cu2O-Ag leads to lower selectivity. On the other hand, Cu2O-Zn catalyst shows superior performance towards C2 products with >50% FE. In addition to C2 products, Cu2O-Zn catalyst shows C3 products such as 1-propanol with 10% FE. In addition to study the effect of secondary metals and oxides, the ECR is investigated under varying applied potentials. This study shows higher FE for C1 products at lower applied potentials. The transition to C2 products occur beyond a certain applied potential which varies for different secondary metals. Overall, this work opens new avenues for achieving higher selectivity towards C2 and C3 products.