Self-decoration of Barium Titanate with Rhodium-NP via a facile co-precipitation route for NO sensing in hot gas environment

• DOI: 10.1016/j.snb.2021.129848
• Publication Date: 2021-03-24T16:37:56Z
• Authors: Roussin Lontio Fo...; Shujie You; Robert Frohnhoven; Tim Ludwig; Sanjay Mathur; Bilge Saruhan
• Keywords: nitrogen oxide; high-temperature sensor; : Rh-loaded BaTiO3; coprecipitation; 7. Clean energy; 01 natural sciences; 0104 chemical sciences

Abstract There is an urgent need to develop real-time gas sensors capable of detection under hot-gas (>400 °C) flow, for applications such as exhaust emission control. In this context, Rh-doped BaTiO3 has been prepared by a co-precipitation route and heat-treated at 900 °C under 2 % hydrogen to obtain in-situ Rh-nanoparticle decoration of submicron BaTiO3 particles. X-ray diffraction, Raman, and X-Ray photoelectron spectrometry analysis confirm the presence of Barium Titanate phases and the substitution of Ti4+ by Rh3+. According to the analytic evidence, thermal hydrogen treatment leads probably to Rhodium diffusion out of titanate lattice, yielding a self-decoration of the nano-sized Barium Titanate particles. Further NO-sensing tests revealed that the sensors produced by deposition of this in-situ Rh-loaded BaTiO3 on the interdigitated electrodes (IDE) yield a significant increase of selectivity and response (∼18 % for 200 ppm NO) towards NO, for the first time, under a hot-gas environment reaching up to 900 °C as synthetic humid air being the carrier gas. The calculated response and recovery times are reasonable, and observed reproducibility confirms suitability to practical applications. Relying on the carried investigations, this good sensing performance can be explained by the creation of excessive oxygen vacancies resulting from Rhodium's surface diffusion. Moreover, it is to claim that excellent catalytic activity of Rhodium plays a key role in enhancing NO-sensing performance.