Electrospun CSNi3C/Fe3C@C/NFs-600 Embedded in Porous Carbon shell as an Efficient Electrocatalyst for Water Splitting at Industrial Driven Current Density

Abstract

Pure-phase carbides suffer from mismatch in H₂ adsorption–desorption kinetics. Herein, we report on heterostructured CSNi₃C/Fe₃C@C/NFs-600 consisting of Co₃C and Ni₃C nanofibers embedded in a graphitic carbon shell synthesized by the electrospinning-magnesiothermic reduction (MTR) process. The Ni₃C/Fe₃C heterojunction core is encapsulated with a porous carbon shell having a large interfacial area, high conductivity, and more exposed active sites, which resulted in moderate hydrogen adsorption energy (E_Hads), increased desorption kinetics, and intriguingly efficient electron transfer. CSNi₃C/Fe₃C@C/NFs-600 exhibits low overpotentials (HER/OER) of 115/191 mV with a small Tafel slope of 56/53 mV dec^–1 and a stability of over 60 h. The activation energy was calculated for electrolysis using CSNi₃C/Fe₃C@C/NFs-600 at 20.00 kJ/mol. The integrated area/number of active sites of CSNi₃C/Fe₃C@C/NFs-600 (4.60 × 10^–5 AV/5.730 × 10¹⁶) confirmed MOOH* formation. The superaerophobicity was substantiated by fast gas bubble evolution from the catalyst surface. Using CSNi₃C/Fe₃C@C/NFs-600, we have produced H₂ efficiently with a lesser power consumption of 651.3 L_H2 kW h^–1. The bifunctional electrolyzer of CSNi₃C/Fe₃C@C/NFs-600 (1.58 V) released vigorous gas bubbles compared to the benchmark electrolyzer of IrO₂/Pt/C/NF (1.64 V) with great stability in alkaline solution. The synthetic strategy with catalyst properties demonstrated here provides perceptions into the future growth of robust bifunctional catalysts for scalable water splitting.