In situ growth of TiO2 on TiN nanoparticles for non-noble-metal plasmonic photocatalysis

Abstract

Plasmonic photocatalysis could provide a promising solution to the two fundamental problems of current TiO₂-based visible-light photocatalysis on low photocatalytic efficiency and low usage of solar illumination. But till now, most plasmonic photocatalysts have relied on noble metal nanostructures of Au or Ag due to their easy synthesis and efficient absorption of visible light. In this study, a TiN/TiO₂ nanocomposite photocatalyst was synthesized by the in situ growth of TiO₂ nanoparticles on TiN nanoparticles with a fluorine-free, vapor-phase hydrothermal process. In this composite photocatalyst system, the desirable visible light absorption could be attributed to the LSPR effect of a nanostructured TiN phase. Thus, a plasmonic photocatalyst without noble-metal components was developed, and its good visible light photocatalytic activity was demonstrated by both the photodegradation of organic pollutants of RhB and 4-NP and the disinfection of microorganisms of E. coli. From the energy alignment analysis, hot electrons were expected to be completely injected from TiN to TiO₂ once they were excited above the Fermi energy level of TiN because no barrier existed, resulting in better electron injection efficiency than previous reported noble-metal-based plasmonic photocatalysts.