Decoration of copper cathodes by gold for electrocatalytic CO 2 reduction in DMF medium

Sedimentation of gold on a copper surface via galvanic replacement (GR) method from (1–4)mM H[AuCl 4 ] + 50 mM Bu 4 NClO 4 solutions in DMF has been studied. It is shown that copper surface decoration (Cu + Au) occurs with the formation of Au nanofilms fragments (0.5 Wt%) and almost solid Au nanofilm (≥ 3.6 Wt%). The main factors influencing the controlled gold content on the copper surface are the concentration of H[AuCl 4 ] and temperature. It was found that the reduction of CO 2 on (Cu + Au) cathodes in DMF solutions occurs at higher current values compared to copper ones, and the cathode currents increases with increasing Au content. Thus, at E = − 3.0 V, i cathode = 10.9, 11.2 and 17.0 mA⋅cm −2 at Au content of 0.5, 0.8 and 3.6 Wt%, while on copper cathodes i cathode = 6.0 mA⋅cm −2 .