Nano-alloy anchored on spent coffee ground-derived N-doped carbon frameworks for an enhanced oxygen reduction reaction and oxygen evolution reaction

Abstract

The development of an efficient electrocatalyst for oxygen reduction and evolution reactions from earth abundant resources is crucial for fuel cells. In this work, the biomass of spent coffee grounds (SCGs) was used as the raw materials for synthesis of electrocatalysts with a porous carbon framework. The NiCo nanoalloy and rich N atoms were incorporated into the obtained porous carbon frameworks. The electronic structure of the carbon atoms was modulated by the NiCo alloy and N heteroatoms, resulting in a synergistic effect that produces a favorable chemical environment for outstanding oxygen electrochemical applications. The catalyst demonstrates excellent ORR performance with a remarkable half-wave potential (E_1/2) of 0.80 V vs. RHE, comparable with the commercial Pt/C catalysts. The catalyst also showed excellent performance for the OER, with an overpotential of 280 mV@10 mA cm⁻². The prepared NiCo@SCG-C is effectively utilized as an air-cathode in a rechargeable Zn–air battery.