Abstract
Semiconductor photocatalysts showing excellent performance under irradiation of both ultraviolet (UV)- and visible (VIS)-light are highly demanded towards realization of sustainable energy systems. TiO2 is one of the most common photocatalysts and has been widely investigated as candidate showing UV/VIS responsive performance. In this study, we report synthesis of Nb doped TiO2 by environmentally benign mechanochemical reaction. Nb atoms were successfully incorporated into TiO2 lattice by applying mechanical energy. As synthesized Nb doped TiO2 were metastable phase and formed chemical compositional gradient structure of poorly Nb doped TiO2 core and highly Nb doped TiO2 surface after high temperature heat treatment. It was found that formed gradient chemical compositional heterojunctions effectively enhanced photocatalytic performance of Nb doped TiO2 under both of UV- and VIS-light irradiation, which is different trend compared with Nb doped TiO2 prepared through conventional methods. The approach shown here will be employed for versatile systems because of simple and environmentally benign process.
Highlights
In the last decade, there is a numerous number of studies about functionality improvement of semiconductor photocatalysts to achieve both of ultraviolet (UV)-light and visible (VIS)-light responsive performance
We focused on the fabrication of Nb doped T iO2 by using mechanochemical process
Heat treated powder of TiNb2O7 was employed as a Nb source in subsequent mechanochemical process because TiNb2O7 was reportedly segregated from Nb doped TiO2 only after high temperature heat treatment that means TiNb2O7 will be highly compatible with TiO232
Summary
There is a numerous number of studies about functionality improvement of semiconductor photocatalysts to achieve both of ultraviolet (UV)-light and visible (VIS)-light responsive performance Several strategies, such as band gap engineering by doping cations and/or anions, modification of surface structures, and design heterojunction with cocatalysts of metals or semiconductors, were employed to achieve UV/VIS responsive photocatalytic performance[1,2,3,4]. Nb doped TiO2 were synthesized through vairous methods, such as pulsed laser deposition[28,29], sol–gel technique[30,31], thermal plasma processing[32], and spray pyrolysis[33], chemical compositional gradient structures have not been reported This indicates that mechanochemically synthesized materials are key to form the gradient structure and enhance photocatalytic property. The method reported here is a simple and facile approach, it is expected to widely apply other dopant-semiconductor systems towards highly functionalized photocatalysts
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
