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

Dual atom catalysts (DACs), are promising electrocatalysts for oxygen reduction reaction (ORR) on account of the potential dual-atom 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-Nx-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 long-term stability up to 10 h in both alkaline and acidic electrolytes. The remarkably enhanced ORR catalytic property of our as-developed DACs is in the rank of excellence for 1%. The as-developed rechargeable Zn-air battery (ZAB) with Fe/Co-SAs-Nx-PCNSs air cathode delivers ultrahigh power density of 216 mW·cm−2, outstanding specific capacity of 813 mAh·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.