Nano-porous hollow Li0.5La0.5TiO3 spheres and electronic structure modulation for ultra-fast H2S detection. Issue 5 (20th November 2019)

• Record Type: Journal Article
• Authors: Zheng, Ningchong; Li, Xiaofeng; Yan, Shen; Wang, Qian; Qiao, Rui; Hu, Junhua; Fan, Jiajie; Cao, Guoqin; Shao, Guosheng
• Is Part Of: Journal of materials chemistry. Volume 8:Issue 5(2020)
• Page Start: 2376
• Page End: 2386
• Publication Date: 2019-11-20
• Subjects: Materials -- Research -- Periodicals; Chemistry, Analytic -- Periodicals; Environmental sciences -- Research -- Periodicals; 543.0284
• DOI: 10.1039/c9ta10482h
• Languages: English
• ISSNs: 2050-7488

Abstract

Abstract : The ultra-fast response of Li0.5 La0.5 TiO3 was first reported and effective modulation of the band structure further enhances the response value. Abstract : Ultra-fast detection of hazardous gases with high selectivity is important for environmental safety monitoring. In this study, we report a Li0.5 La0.5 TiO3 (LLTO) sensor with an ultrafast response to H2 S. We used a simple solvothermal method to controllably synthesize hollow LLTO nano-spheres. The LLTO nano-spheres had a porous surface structure, which provides sufficient channels for diffusion of H2 S gas. Response/recovery speeds of 0.7 s/0.8 s were achieved at an optimum working temperature of 340 °C. To further improve the response, the band structure was modulated by Fe doping (FLTO). When doped with Fe 3+, more oxygen vacancies were generated which enhanced the chemical absorption of O2 and generation of active oxygen species (O − and O 2− ). Furthermore, the band gap was also narrowed and the conduction band was elevated by 0.44 eV, which promoted charge transfer from the conduction band of FLTO to chemisorbed gas molecules. After doping, the response was 5.5 times as great as that of the pristine LLTO sensor for 30 ppm H2 S and the optimum temperature decreased to 300 °C. In addition, the detection limit was as low as 100 ppb. The doped LLTO sensor also had good repeatability and long-term stability.