a Partial ethanol current density of Ce(OH)x/Cu/PTFE and bare Cu/PTFE under various potentials. b Product distribution of Ce(OH)x/Cu/PTFE and bare Cu/PTFE at the −0.7 V versus RHE. c Energy efficiency as a function of partial current density on Ce(OH)x/Cu/PTFE, in comparison with other reports with operational current density higher than 10 mA cm−2. d i–t curve (left axis) of Ce(OH)x/Cu/PTFE catalyst along with corresponding Faradaic efficiency of ethanol (right axis). e Product distribution of various hydroxides/oxides modified Cu/PTFE electrode, along with corresponding C2H5OH/C2H4 ratio. The error bars represent the standard deviation from at least three independent tests.