Enhanced photocatalytic hydrogen evolution activity of carbon and nitrogen self-doped TiO2 hollow sphere with the creation of oxygen vacancy and Ti3+. (December 2018)

• Record Type: Journal Article
• Authors: Zhang, Dainan; Ma, Xiyang; Zhang, Huaiwu; Liao, Yulong; Xiang, Quanjun
• Is Part Of: Materials today energy. Volume 10(2018)
• Page Start: 132
• Page End: 140
• Publication Date: 2018-12
• Subjects: Titanium dioxide -- Self-doping -- Hollow sphere -- Oxygen vacancy -- Ti3+; Energy development -- Periodicals; Energy industries -- Periodicals; Power resources -- Periodicals; Energy policy -- Periodicals; Energy development; Energy industries; Energy policy; Power resources; Electronic journals; Periodicals; 621.042
• DOI: 10.1016/j.mtener.2018.08.018
• Languages: English
• ISSNs: 2468-6069

Abstract

Abstract: Introducing oxygen vacancies and Ti 3+ into TiO2 is thought to be an effective method of increasing the utilization of sunlight and promoting the efficiency of electron transfer. In this work, novel carbon and nitrogen self-doped TiO2 hollow spheres (CNTH) with oxygen vacancies and Ti 3+ were synthesized by a one-pot hydrothermal strategy in H2 OC2 H5 OHHFH2 O2 mixed solution with TiCN as a precursor of anatase TiO2 and self-doping source of N and C. The presence of oxygen vacancies and Ti 3+ in the resulting CNTH photocatalyst was supported by electron paramagnetic resonance (EPR) and X-ray absorption near-edge structure spectroscopy (XANES). X-ray photoelectron spectroscopy (XPS) analysis showed that the C and N atoms were successfully self-doped into TiO2 lattice, which resulted in the CNTH materials exhibiting the enhanced absorption in the UV–visible region with a clear red shift at the absorption edges. The electronic structure of CNTH was examined by first-principle density functional theory (DFT) calculations, which further confirmed the optical properties of CNTH for the enhanced visible-light absorption properties and the red-shift phenomenon of the absorption edges. The resulting CNTH photocatalyst showed enhanced visible-light photocatalytic activity for H2 production. The enhanced activity of CNTH was due to the introduction of C and N self-doping and the existence of oxygen vacancies and Ti 3+ . The former can promote the photocatalytic reactions of the photogeneration electrons and holes on CNTH under visible-light irradiation, while the latter create more active sites and prolong the life time of electrons and holes by their donor states. Highlights: Novel carbon and nitrogen self-doped TiO2 hollow spheres (CNTH) with oxygen vacancies and Ti 3+ were synthesized. The existence of oxygen vacancies and Ti 3+ in CNTH was confirmed by EPR and XANES. The enhanced activity was due to the introduction of C and N self-doping and the existence of oxygen vacancies and Ti 3+ .