Synthesis of dual-metal single atom in porous carbon with efficient oxygen reduction reaction in both acidic and alkaline electrolytes

The rational design and fabrication of platinum group metal-free (PGM-free) electrocatalysts for oxygen reduction reaction (ORR) via economically feasible approach is essential for reducing the cost of fuel cells and metal-air batteries. Catalysts must have very high activity, and excellent mass diffusion of reactants. Herein, we display a high-performing dual-metal single atom catalyst (DM-SAC) composed of Fe and Ni SA active sites immobilized in porous carbon nanospheres (Fe/Ni-N-PCS), prepared via defects/vacancies anchoring strategy. The abundant and accessible edge-hosted Fe and Ni SA active sites can promote the adsorption/desorption behavior for ORR intermediates attributing to possible synergistic effects between dual-metal SA active sites. Thus, the as-developed Fe/Ni-N-PCS DM-SAC exhibits impressive ORR electro-catalytic performance in both alkaline (Eonset = 1.04 V, E1/2 = 0.9 V) and acid solutions (Eonset = 0.87 V, E1/2 = 0.71 V), and high stability, outperforming SACs with solo Fe-Nx or Ni-Nx active sites, and benchmark PGM. Fe/Ni-N-PCS also exhibits superior oxygen evolution reaction (OER) performance with low overpo-tential and long-term stability. Zn-air battery with Fe/Ni-N-PCS cathode yields encouraging performance, including working potential, peak power density, and the stability of charge and discharge cycles. Our synthesis method may promote the fabrication of other DM-SAC and the great promise in practical applications.(c) 2022 Elsevier Inc. All rights reserved.

Automated summary

This study presents a dual-metal single atom catalyst (DM-SAC) composed of Fe and Ni SA active sites immobilized in porous carbon nanospheres. The catalyst exhibits impressive performance in both alkaline and acid solutions for oxygen reduction reaction (ORR), as well as superior performance in oxygen evolution reaction (OER). The synthesis method shows potential for practical applications.