Scalable fabrication of high activity nanoporous copper powders for electrochemical CO2 reduction via ball milling and dealloying

•Scalable fabrication of nanoporous copper powders through ball milling and dealloying.•Nanoporous copper powder catalysts for electrochemical CO2 reduction in a commercially relevant MEA electrolyzer.•Peak ethylene Faradaic efficiency of 34% at 75-100 mA/cm2 with a hydrogen Faradaic efficiency below 30%.•Bridges the gap between lab-scale ECR catalyst development and the need of an emerging ECR industry.