Intermetallic CuAu nanoalloy for stable electrochemical CO2 reduction

Copper is one of the most efficient catalysts widely investigated in electrochemical CO2 reduction, however, the further development of copper-based catalysts is constrained by severe stability problems. In this work, we developed a method for the synthesis of highly ordered CuAu intermetallic nanoalloys (o-CuAu) under mild conditions (< 250 °C), which can convert carbon dioxide to carbon monoxide with high selectivity and can operate stably for 160 h without current decay. The improved stability is believed to be due to the increased mixing enthalpy and stronger atomic interactions between Cu and Au atoms in the intermetallic nanoalloy. In addition, XPS results, Tafel slope and in situ IR spectroscopy demonstrate that high valence gold atoms on o-CuAu surface promote the reduction of CO2. In contrast, the disordered CuAu nanoalloy (d-CuAu) underwent atomic rearrangement to form a Cu-rich structure on the surface, leading to reduced stability. These findings may provide insight into the rational design of stable CO2RR electrocatalysts through proper structural engineering.