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

Herein, tungsten-coated nano-boron carbide (W-WB4 -WCx /B4 C) particles were prepared by heating a mixture of B4 C 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 B4 C to form WCx , WB4 , and graphite nanoribbons. The oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) performance of W-WB4 -WCx /B4 C is tested in an alkaline solution, and the results show that the W-WB4 -WCx /B4 C 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 -WCx /B4 C composites is attributed to their unique structure, in which WCx and WB4 not only improve the catalytic activity for the OER and HER, but also effectively anchor the W coating on the substrate.