Controlling incorporation of TiO2 nanoparticles in the carbonization process: a new strategy to develop a nitrogen-doped carbon-based Mo2C@TiO2 electrocatalyst for electrochemical hydrogen evolution reaction

Abstract

The rational design of an active and stable electrocatalyst for the hydrogen evolution reaction (HER) is demonstrated as a major challenge for the renewable energy-driven water-splitting process. Herein, a unique structure of nitrogen-doped carbon-based Mo₂C@TiO₂ (NC/Mo₂C@TiO₂) was synthesized via controlling incorporation of TiO₂ nanoparticles in the carbonization process to achieve promising electrocatalytic activity towards the HER. The electronic structure of Mo₂C nanodots was regulated by TiO₂ and nitrogen-doped carbon, thus exposing abundant active sites for the HER. Electrochemical measurement shows that the NC/Mo₂C@TiO₂ electrocatalyst has a low overpotential of 167 mV at 10 mA cm⁻² with a Tafel slope of 158 mV dec⁻¹ in 1 M KOH. The electrocatalyst shows excellent stability with a slightly declined current density of 92.88% after 35 h of operation because of the involvement of TiO₂. Moreover, the design concept can be extended to developing other transition metal carbide electrocatalysts.