Spatial confinement of zeolitic imidazolate framework deposits by porous carbon nanospheres for dual-atom catalyst towards highperformance oxygen reduction reaction

Dual atom catalysts (DACs), are promising electrocatalysts for oxygen reduction reaction (ORR) on account of the potential dualatom active sites for the optimized adsorption of catalytic intermediates and the lower reaction energy barriers. Herein, spatial confinement strategy to fabricate DACs with well-defined Fe, Co dual-atom active site is proposed by implanting zeolitic imidazolate frameworks inside the pores of highly porous carbon nanospheres (Fe/Co-SAs-N-x-PCNSs). The atomically dispersed dual-atom active sites facilitate the adsorption/desorption of intermediates. Furthermore, the spatial confinement effect protects metal atoms aggregating. Benefiting from the rich accessible dual-atom active sites and boosted mass transport, we achieve remarkable ORR performance with half-wave potential up to 0.91 and 0.8 V (vs. reversible hydrogen electrode (RHE)), and longterm stability up to 10 h in both alkaline and acidic electrolytes. The remarkably enhanced ORR catalytic property of our asdeveloped DACs is in the rank of excellence for 1%. The as-developed rechargeable Zn-air battery (ZAB) with Fe/Co-SAs-N(x)PCNSs air cathode delivers ultrahigh power density of 216 mW center dot cm-2, outstanding specific capacity of 813 mAh center dot g(-1), and promising cycling operation durability over 160 h. The flexible Zn-air battery also exhibits excellent specific capacity, cycling stability, and flexibility performance. This work opens up a new pathway for the multiscale design of efficient electrocatalysts with atomically dispersed multiple active sites.