Turning Harmful Deposition of Metal Impurities into Activation of Nitrogen-Doped Carbon Catalyst toward Durable Electrochemical CO 2 Reduction

Electrochemical CO 2 reduction is typically operated under highly refined electrolyte conditions. However, trace amounts of metal impurities exist even in ultrapure electrolyte solutions, causing a fatal deactivation of the catalysts. To address this issue, various efforts have been made to prevent the harmful deposition of metal impurities on the catalyst. Herein, we designed a new system where metal impurities are utilized as activators. We demonstrated “self-activation” of the N-doped carbon catalyst in the presence of Fe impurity with remarkable stability for 120 h. The origin of the self-activation was the selective adsorption of Fe impurity forming highly dispersed Fe sites through Fe–N interactions. The correlations between the self-activation and number of N sites and their moieties were investigated and further generalized into other metals, such as Ni, Zn, and Cu. This novel ge…