Structural engineering of robust titanium nitride as effective platinum support for the oxygen reduction reaction

Abstract

The development of both effective and robust catalysts is crucial for the commercialization of polymer electrolyte membrane fuel cells since the reactivity and durability of the catalysts determine its ultimate lifetime and activity. Herein, we developed a facile approach for the synthesis of porous and hierarchical mono- or bi-metallic titanium nitride nanotubes (NTs), and this robust non-carbon material was used as the Pt support. The optimized catalyst (Pt/Ti_0.9Ni_0.1N NTs) demonstrated a mass activity of 0.78 A mg_Pt⁻¹ and a specific activity of 1.3 mA cm⁻² at 0.9 V (vs. RHE), which is roughly 3.6 times that of the commercial Pt/C catalyst. In particular, the catalyst exhibited excellent stability, such that the mass activity remained 3.2 times greater than that of pristine commercial Pt/C even after 15 000 continuous cycles at up to 1.2 V; in addition, the structure of the catalyst was perfectly maintained. The experimental data demonstrates that the hollow and porous structures, the strong metal-support interaction, and the synergistic effects derived from the nickel doping contribute to the improved performance and durability of the catalyst. This study paves the way for the rational synthesis of robust non-carbon catalysts that can be applied in a wide range of energy conversion processes.