NiCoFe alloy multishell hollow spheres with lattice distortion to trigger efficient hydrogen evolution in acidic medium

Defect engineering or lattice distortion is considered an efficient strategy to enhance the intrinsic activity of an electrocatalyst. Multishell, hollow NiCoFe alloy spheres were prepared with vacancies, gaps or defect, and tilting of an atomic plane with incorporated graphitic carbon derived from the surfactant. The extra gaps or defects in the lattice, which can be verified by high-resolution transmission electron microscope, provide additional active edge sites for the hydrogen evolution reaction. As a result, three-dimensional NiCoFe alloy poses a very low overpotential of 16 mV in 0.5 M H₂SO₄ for the hydrogen evolution reaction and an unexpectedly small Tafel slope of 38 mV dec^-1. This work can therefore broaden horizons and provide a new dimension for the design of new, highly efficient electrocatalysts for hydrogen evolution in an acidic medium.