Advanced Design of Metal Nanoclusters and Single Atoms Embedded in C 1 N 1 ‐Derived Carbon Materials for ORR, HER, and OER

Single atoms and nanoclusters of Fe, Ni, Co, Cu, and Mn are systematically designed and embedded in a well‐defined C 1 N 1 ‐type material that has internal cavities of ≈0.6 nm based on four N atoms. These N atoms serve as perfect anchoring points for the nucleation of small nanoclusters of different metal natures through the creation of metal‐nitrogen (TM‐N 4 ) bonds. After pyrolysis at 800 °C, TM@CN x ‐type structures are obtained, where TM is the transition metal and x < 1. Fe@CN x and Co@CN x are the most promising for oxygen reduction reaction and hydrogen evolution reaction, respectively, with a Pt‐like performance, and Ni@CN x is the most active for oxygen evolution reaction (OER) with an E OER of 1.59 V versus RHE, far outperforming the commercial IrO 2 ( E OER = 1.72 V). This systematic and benchmarking study can serve as a basis for the future design of advanced multi‐functional electrocatalysts by modulating and combining the metallic nature of nanoclusters and single atoms.