Two‐step hydrothermal fabrication of Na 0.23 TiO 2 nanofibers and enhanced photocatalysis after loaded with gold or silver determined by surface potentials

Summary Pure Na 0.23 TiO 2 nanofibers were fabricated by a two‐step hydrothermal method after a series of experiments. Na 0.23 TiO 2 is a direct bandgap semiconductor and exhibits a strong photodegradative ability for RhB, which is difficult to be degraded. The photodegradative activity is much enhanced after loaded noble metal Au or Ag nanoparticles on Na 0.23 TiO 2 nanofibers by a chemical bath deposition method. Hot electrons are generated in metal nanoparticles through a localized surface plasmon (LSP) process under light illumination and then diffuse to a semiconductor and reduce the surface potential, which is detected directly by a scanning Kelvin probe microscopy (SKPM). The high electromagnetic field induced by the LSP resonance and strong coupling between noble metal and Na 0.23 TiO 2 are beneficial for the utilization of visible light, electron produce, charge transportation, and separation, as a result, promoting the activity of semiconductor‐based photocatalysts. This work supplies an effective method to directly probe the surface plasmon and highlights the application of Na 0.23 TiO 2 in photocatalysis.