A General Method for Transition Metal Single Atoms Anchored on Honeycomb‐Like Nitrogen‐Doped Carbon Nanosheets

Abstract

Excavating and developing highly efficient and cost‐effective nonnoble metal single‐atom catalysts for electrocatalytic reactions is of paramount significance but still in its infancy. Herein, reported is a general NaCl template‐assisted strategy for rationally designing and preparing a series of isolated transition metal single atoms (Fe/Co/Ni) anchored on honeycomb‐like nitrogen‐doped carbon matrix (M 1‐HNC‐T 1‐T 2, M = Fe/Co/Ni, T1 = 500 °C, T2 = 850 °C). The resulting M 1‐HNC‐500‐850 with M‐N 4 active sites exhibits superior capability for oxygen reduction reaction (ORR) with the half‐wave potential order of Fe 1‐HNC‐500‐850 > Co 1‐HNC‐500‐850 > Ni 1‐HNC‐500‐850, in which Fe 1‐HNC‐500‐850 shows better performance than commercial Pt/C. Density functional theory calculations reveal a choice strategy that the strong p–d‐coupled spatial charge separation results the Fe‐N 4 effectively merges active electrons for elevating d‐band activity in a van‐Hove singularity like character. This essentially generalizes an optimal electronic exchange‐and‐transfer (ExT) capability for boosting sluggish alkaline ORR activity. This work not only presents a universal strategy for preparing single‐atom electrocatalyst to accelerate the kinetics of cathodic ORR but also provides an insight into the relationship between the electronic structure and the electrocatalytical activity.