Study on Strategy to Incorporate Carbon and Nitrogen in Nanostructured TiO2: Modification of Low Bandgap Initiated by Broad Spectrum Response and Its Photoelectrochemical Properties

Abstract

A material of nitrogen, carbon-codoped TiO 2 (HITNC-1) with an unusual optical property in the near-infrared region is prepared at 800 °C in NH 3 and CO 2 atmosphere. TEM results show semiconductor nanocrystals with grain size approximately in the range of 2～8 nm. HITNC-1 exhibits two strong absorption bands in near-infrared region, which is relative with the F-type color centers produced by the behaviors of Ti 3+ trapping electrons and lies on the doping of N,C atoms into TiO 2 lattices. The results of the surface photovoltage spectrum indicate that the intensity of positive photovoltage signal is 20 times than raw TiO 2 , and emerges a new signal in NIR region. The transient photovoltage results provide the investigation of dynamic behavior of photo-induced charge carriers in HITNC-1. Therefore, the photoelectrochemical properties clearly demonstrate that N,C-codoped TiO 2 at high temperature could induce the separation of e − and h + and harvest photons for optical property.