Interfacial engineering-induced electronic regulation drastically enhances the electrocatalytic oxygen evolution: Immobilization of Janus-structured NiS/NiO nanoparticles onto carbon nanotubes/nanofiber-integrated superstructures.

• A feasible electrospinning strategy was proposed to construct a 1D/1D hierarchical superstructure. • NiS/NiO hetero-nanoparticles immobilized firmly in such hierarchical superstructures. • NiS/NiO@N-C NT/NFs demonstrate prominent OER performance in alkaline electrolyte. • The chemisorption energies of the oxygen-related intermediates are optimized by NiS/NiO heterojunction. Electronic regulation via interfacial engineering is a versatile strategy to boost the efficiency of earth-abundant electrocatalysts for the oxygen evolution reaction (OER). Herein, we demonstrate the combination of interfacial manipulation with nanoarchitectonics by elaborately designing Janus-structured NiS/NiO nanoparticles in-situ encapsulated within N-doped carbon nanotube "branches"/nanofiber "trunk"-typed superstructures (abbreviated as NiS/NiO@N-C NT/NFs hereafter) to effectively regulate the electronic configuration for expediating the OER process. The simultaneous realization of interfacial engineering and nanoarchitectonics renders the resultant NiS/NiO@N-C NT/NFs with optimized electronic configuration, increased oxygen vacancies, promoted mass diffusion channels and remarkable structural robustness. Therefore, the NiS/NiO@N-C NT/NFs exhibit outstanding OER activity with a small overpotential of 269 mV at 10 mA cm−2 and impressive long-term stability in alkaline electrolyte, representing an economical and competetive electrocatalyst for a number of sustainable energy devices. Density functional theory (DFT) simulations further validate that the formation of NiS/NiO heterojunction effectively tailors the chemisorption energies of the oxygen-related intermediates and reduces the reaction barrier, drastically accelating the OER kinetics. These findings demonstrating the significance of interface manipulation and hybridization with nanocarbon may offer a novel perspective for rational design of high-performance electrocatalysts towards the energy storage and conversion. [ABSTRACT FROM AUTHOR]