Electrocatalytic behaviour of titanium implanted with nickel and molybdenum ions

Abstract

The electrocatalytic activity of titanium induced by ion implantation has been investigated. Ion implantation was carried out using a metal vapour vacuum arc source ion implanter at room temperature. Nickel ion implantation was followed by molybdenum ion implantation at doses ranging from 1 × 1016 to 1 × 1017 ions/cm2 at the same average extracting voltage of 45 kV. The concentration profiles of Ni and Mo ions in the near surface were detected by electron probe microanalysis and X-ray photoelectron spectroscopy. The catalytic behaviour of implanted titanium was determined by an electrochemical method. Potential versus current density curves for the cathodic hydrogen evolution reaction indicated that Ni and Mo ions implanted into titanium electrodes resulted in a low hydrogen overvoltage of 110-180 mV (at a current density of 200-400 mA cm-2 in 30 wt-%KOH at 25°C) and excellent stability. The electrocatalytic activity induced by ion implantation can be explained provisionally by interactions between Ni and Mo ions and the titanium substrate.