Electrocatalytic activity of WB2 electrodes for hydrogen evolution reaction prepared by different methods

Abstract

Tungsten diboride (WB₂) exhibits excellent catalytic activity and stability in the hydrogen evolution reaction (HER) of water electrolysis, which are found to be closely related to the processing method of the electrode. In the present work, flake-like WB₂ powder was used to prepare self-supported electrodes through spark plasma sintering (SPS) at 750, 800, and 1600 °C, respectively, as well as cold isostatic pressing (CIP), with the electrode prepared by drop-casting from powder direction. The results showed that, in an acidic medium, the sample sintered at 750 °C exhibited an overpotential of 141.6 mV at 10 mA/cm², with a corresponding Tafel slope of 42.1 mV/dec, which demonstrated a high catalytic activity. In addition, the experimental results showed that the WB₂ particles bonded together to form a porous network structure after SPS low-temperature sintering, resulting in a high density of actively catalytic sites, reduced electron transfer impedance, and exceptional long-term stability.