Synergistic electronic and structural engineering via zinc doping for high-performance multifunctional FeCo alloy...

Developing high-activity, low-cost and stable multifunctional electrocatalysts remains crucial yet challenging for advancing energy technologies. Zn offers unique advantages for achieving high-performance electrocatalysts due to its low electronegativity-favourable for electronic modulation-and its low boiling point, which facilitates engineering during the synthesis process. Leveraging these dual characteristics, we computationally predicted the effects of Zn doping and rationally designed a Zn-doped FeCo alloy anchored on hierarchically porous carbon nanofiber with a protective surface carbon film (Zn-FeCo@CNF-900). Density functional theory calculations further reveal that Zn-induced charge transfer to Fe/Co, along with the lowering of the d-band centre, optimises the adsorption energies of key reaction intermediates. Simultaneously, pore formation during calcination enhances mass and electron transport, while the carbon film stabilises active sites. Benefitting from this synergistic modulation, the resulting Zn-FeCo@CNF-900 exhibits an outstanding half-wave potential of 0.84 V for the oxygen reduction reaction (ORR), and an overpotential of 268 mV at a current density of 10 mA cm^-2 for the oxygen evolution reaction (OER). In a Zn-air battery (ZAB), Zn-FeCo@CNF-900 delivers exceptional stability (>600 h) and a high-power density of 195 mW cm^-2. Furthermore, this multifunctional electrocatalyst enables a ZAB-driven overall water splitting system. This study integrates computational design with experimental validation to develop high-performance multifunctional electrocatalysts through targeted electronic and structural engineering.