Tungsten-coated nano-boron carbide as a non-noble metal bifunctional electrocatalyst for oxygen evolution and hydrogen evolution reactions in alkaline media

Abstract

Herein, tungsten-coated nano-boron carbide (W-WB₄-WC_x/B₄C) particles were prepared by heating a mixture of B₄C and W powder using a spark plasma coating (SPC) method. During the discharge treatment process, metal W in the mixture is activated and reacts with B₄C to form WC_x, WB₄, and graphite nanoribbons. The oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) performance of W-WB₄-WC_x/B₄C is tested in an alkaline solution, and the results show that the W-WB₄-WC_x/B₄C composite electrocatalyst exhibits a low overpotential of 0.36 V at 10 mA cm⁻² for the OER, a small overpotential of −0.19 V (j = 10 mA cm⁻²) for the HER, as well as good stability. The significantly enhanced electrocatalytic performance of the W-WB₄-WC_x/B₄C composites is attributed to their unique structure, in which WC_x and WB₄ not only improve the catalytic activity for the OER and HER, but also effectively anchor the W coating on the substrate.