Communication—Electrodeposited Co–Mo–P–TiO₂ Composites Electrocatalysts for the Hydrogen Evolution Reaction

Abstract

A Co–Mo–P–TiO 2 composite electrocatalyst is electrodeposited for the first time and the hydrogen evolution reaction (HER) was characterized. The HER Tafel slope and exchange current density on the Co–Mo–P–TiO 2 surface were compared with Co–Mo, Co–Mo–TiO 2 and Co–Mo–P electrodeposits similarly prepared with comparable Co/Mo composition ratio. The Co–Mo–P–TiO 2 exhibited a very low overpotential at −10 mA cm −2 of 31 mV in a 1 M NaOH electrolyte. The electrochemical active surface area was characterized, to show that the improvement is not merely due to surface roughness but is an intrinsic effect. The role of TiO 2 and P differed in the Co–Mo electrodeposit.