Elaborate tree-like Cu-Ag clusters from green electrodeposition for efficiently electrocatalyzing CO 2 conversion into syngas.

The electrocatalytic carbon dioxide reduction (CO 2 RR) is one of the emerging technologies that can effectively transform carbon dioxide (CO 2 ) into valuable products. Electrocatalysts deriving from green synthesis methods will significantly help to establish a new green carbon cycle. Herein, a green electrodeposition method without additional reducing agents was used to synthesize Cu-Ag bimetallic catalysts, and it is shown that the combination of Cu and Ag obviously affects the morphology of the Cu-Ag catalysts, resulting in the formation of elaborate tree-like Cu-Ag clusters. An as-deposited Cu-Ag/carbon fiber (Cu-Ag/CF) catalyst exhibits high activity, selectivity and stability toward the CO 2 RR; in particular, the elaborate dendritic Cu-Ag/CF can efficiently reduce CO 2 to syngas with high selectivity (Faradaic efficiency (FE) > 95%) at a low onset potential (-0.5 V). This work provides a rational strategy to overcome the significantly different reaction capacities during the reduction of Ag + and Cu 2+ , leading to the formation of a controlled morphology of Cu-Ag, which is favourable for the design and development of highly efficient Cu or Ag catalysts via green methods for electrocatalyzing the CO 2 RR.