Electrocatalytic activity of α‐MoB₂ porous self‐supported electrodes for the HER: The effects of sintering temperature

Abstract α‐MoB 2 , which has been considered as one of the promising nonprecious transition metal borides catalysts for the hydrogen evolution reaction (HER), has recently been reported to be very efficient in the bulk form (self‐supported electrode). However, bulk α‐MoB 2 is normally synthesized under high‐temperature and high‐pressure conditions. In the present work, α‐MoB 2 porous self‐supported electrodes with relative density of ∼52%–55% were synthesized by a combination of mechano‐chemical process and low‐temperature (750°C, 800°C, 850°C, and 900°C) spark plasma sintering technique. The effects of the sintering temperature on HER activity of the self‐supported electrodes in acidic solution were investigated in this study. The results showed that an overpotential as low as 91.2 mV at a current density of 10 mA/cm 2 , and a Tafel slope of 61.8 mV/dec were obtained by the α‐MoB 2 electrode prepared at 850°C. This is the lowest overpotential value of the pure α‐MoB 2 at a current density of 10 mA/cm 2 ever reported in the open literature. Thus, the present study provides a new insight into the potentially innovative approach to manufacture α‐MoB 2 porous self‐supported electrodes with excellent HER performance.