Nanoporous TiCN with High Specific Surface Area for Enhanced Hydrogen Evolution Reaction

Transition-metal nitrides have attracted significant attention because of their unique electronic and surface properties and superior chemical and mechanical stability. Although various metal nitrides nanostructures have been realized, it remains challenging to introduce porosity and the high specific surface in these nanostructures, but they are required to expand the application possibility of these materials in energy storage and conversion. Here, we report the preparation of nanoporous titanium carbonitride using a high-nitrogen-containing mesoporous carbon nitride, C₃N₆(MCN-4), as a reactive template and titanium tetrachloride as the titanium source. Nitrogen adsorption and microscopic results reveal that the prepared samples are highly nanoporous in nature, and the optimized sample exhibits a specific surface area of 700 m²/g and a high specific pore volume of 1.3 cm³/g. With the slight variation of the amount of MCN-4 in the synthesis mixture, the composition and the crystal structure of the nanoporous titanium carbonitride can be finely controlled. Near-edge X-ray absorption fine structure and Raman spectroscopic analyses of these samples confirm that the titanium atoms are strongly bonded with both carbon and nitrogen. The electrochemical hydrogen evolution reaction measurements of the optimized nanoporous titanium carbonitride loaded with 5 wt % of platinum in acidic medium reveal a high electrocatalytic performance with the overpotential of 27 mV at the current density of 10 mA cm^-2, which is similar to that of commercially available Pt/C which contains 20 wt % of Pt. The combination of nanoporous structure together with the highly conducting carbon matrix in these metal carbonitride samples really helps to enhance the electrocatalytic activity. This research reveals a great opportunity for the design of porous metal nitride-based nanostructures with different composition and the potential for these materials to be used in energy storage and conversion technologies.