Electro-functionalized 2D nitrogen-carbon nanosheets decorated with symbiotic cobalt single-atoms/clusters

Two-dimensional (2D) materials loaded with single atoms and clusters are being set at the forefront of catalysis due to their distinctive geometric and electronic features. However, the usually-complicated synthesis procedures impede in-depth clarification of their catalytic mechanisms. To this end, herein we developed an efficient one-step dimension-reduction carbonization strategy, with which we successfully architected a highly-efficient catalyst for oxygen reduction reaction (ORR), featured with symbiotic cobalt single atoms and clusters decorated in two-dimensional (2D) ultra-thin (3.5 nm thickness) nitrogen-carbon nanosheets. The synergistic effects of the two components afford excellent oxygen reduction activity in alkaline media (E1/2 = 0.823 V vs. RHE) and thereof a high power density (146.61 mW cm-2) in an assembled Zn-air battery. As revealed by theoretical calculations, the cobalt clusters can regulate electrons surrounding those individual atoms and affect the adsorption of intermediate species. As a consequence, the derived active sites of single cobalt atoms lead to a significant improvement of the ORR performance. Thus, our work may fuel interests to delicate architecture of single atoms and clusters coexisting 2D support toward optimal electrocatalytic performance. (c) 2024 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. and Science Press. All rights are reserved, including those for text and data mining, AI training, and similar technologies.