Cu-Ni-CoSex quaternary porous nanocubes as enhanced Pt-free electrocatalysts for highly efficient dye-sensitized solar cells and hydrogen evolution in alkaline medium

Abstract

A series of porous cubic nanomaterials have been prepared through a facile one-step selenylation process, in which Cu-Ni-Co, Ni-Co and Cu-Co Prussian-blue analog nanocubes transformed to Cu-Ni-CoSe_x, Ni-CoSe_x and Cu-CoSe_x nanocubes, respectively. Among these samples, the quaternary porous nanocubes (Cu-Ni-CoSe_x) proved to be the excellent bifunctional electrocatalysts in dye-sensitized solar cells and hydrogen evolution reactions. Under the standard irradiation, Cu-Ni-CoSe_x nanocubes exhibited a high power conversion efficiency of 9.74% in solar cells, which was much superior than that of Pt (8.19%). Cu-Ni-CoSe_x nanocubes also delivered superb hydrogen evolution performance in terms of a low overpotential (50.2 mV) under the current density of 10 mA cm⁻² and a low Tafel slope (49.6 mV dec⁻¹) in alkaline medium. The outstanding characteristics of Cu-Ni-CoSe_x nanocubes were benefited from their uniform sizes, porous morphologies, high surface area, low charge transfer resistances and good synergies among multiple elements.