Confined Synthesis of Dual‐Atoms Within Pores of Covalent Organic Frameworks for Oxygen Reduction Reaction

Abstract

Dual‐atom catalysts exhibit higher reactivity and selectivity than the single‐atom catalysts. The pyrolysis of bimetal salt precursors is the most typical method for synthesizing dual‐atomic catalysts; however, the finiteness of bimetal salts limits the variety of dual‐atomic catalysts. In this study, a confined synthesis strategy for synthesizing dual‐atomic catalysts is developed. Owing to the in situ synthesis of zeolitic imidazolate frameworks in the pores of covalent organic frameworks (COFs), the migration and aggregation of metal atoms are suppressed adequately during the pyrolysis process. The resultant catalyst contains abundant Zn─Co dual atomic sites with 2.8 wt.% Zn and 0.5 wt.% Co. The catalyst exhibits high reactivity toward oxygen reduction reaction with a half‐wave potential of 0.86 V, which is superior to that of the commercial Pt/C catalyst. Theoretical calculations reveal that the Zn atoms in the Zn─Co dual atomic sites promote the formation of intermediate OOH*, and thus contribute to high catalytic performance. This study provides new insights into the design of dual‐atom catalysts using COFs.

Construction of imide‐linked covalent organic frameworks with palladium nanoparticles for oxygen reduction reaction

“…Various COFs with different skeletons, porosities and topologies have been developed to explore their properties and functions, such as gas uptakes, 6,7 water harvesting, 8,9 chemical sensor, 10,11 proton/lithium‐ion conduction, 12,13 photocatalysis, 14,15 and electrocatalysis 16,17 . Particularly, COFs have been widely employed in electrocatalytic systems, such as the oxygen evolution, 18,19 oxygen reduction reaction (ORR), 20–22 carbon dioxide reduction 23–25 and nitrogen reduction reaction 26,27 …”