Tailoring acidic microenvironments for carbon-efficient CO2 electrolysis over a Ni–N–C catalyst in a membrane electrode assembly electrolyzer

By tailoring the microenvironments of a Ni–N–C catalyst in an acidic MEA electrolyzer, we achieve a CO faradaic efficiency of 95% at 500 mA cm−2, and the CO2 loss is reduced by 86% at 300 mA cm−2 at pH 0.5, compared to alkaline CO2 electrolysis.