Tailoring acidic microenvironments for carbon-efficient CO2electrolysis 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 CO 2 loss is reduced by 86% at 300 mA cm −2 at pH 0.5, compared to alkaline CO 2 electrolysis.