Modulating *CO coverage via the pyrrolic-N content on carbon for enhanced electrocatalytic CO2 reduction to CO

Abstract

The electrocatalytic CO₂ reduction reaction (eCO₂RR) is a new energy technology that shows a feasible way to achieve carbon neutrality and to produce valuable fuels and feedstocks with effective electrocatalysts. Nitrogen-doped carbon (NC) materials have become the most promising carbon-based electrocatalysts to produce CO and potential metal carriers to produce multi-carbon products due to their low cost, high activity, and ability to enhance metal–carrier interactions. However, aiming at high selectivity of CO, it is important to optimize the competing coverage of *CO and *H on the NC working electrocatalyst surface. Here, for the first time, we controllably adjusted the pyrrolic-N content on NC via a simple strategy of pyrrolic-N-abundant phthalocyanine-assisted pyrolysis of a common MOF precursor (ZIF-8), which then modulated the *CO and *H coverage for enhanced electrocatalytic CO₂ reduction to CO with an FE_CO value of above 92% at −0.6 V vs. RHE. Mechanistic studies showed that the high content of pyrrolic-N of Pr-a-NC induced the surface coverage of *CO to be much higher than that of the control samples. Meanwhile, under the conditions of high *CO coverage, adsorbed *CO intermediates combined with the active *H generated the high-coverage intermediate *COH, which is one of the most common intermediates to generate multi-carbon products. So, this work not only provides an effective strategy for the future rational design of carbon electrocatalysts to generate CO, but also opens an avenue to engineer carbon–nitrogen coordination substrate-loaded metal electrocatalysts for the production of multi-carbon products from the eCO₂RR.