Flame-spray-made PtO<inf>x</inf>-functionalized Zn<inf>2</inf>SnO<inf>4</inf> spinel nanostructures for conductometric H<inf>2</inf> detection

Abstract

© 2020 Elsevier B.V. In this work, 0–3 wt% PtOx-loaded Zn2SnO4 nanoparticles synthesized for the first time by a single-nozzle flame spray pyrolysis (FSP) were studied for hydrogen (H2) detection. Structural characterizations by X-ray diffraction, X-ray photoelectron spectroscopy, electron microscopy, and nitrogen adsorption revealed that PtOx nanoparticles with the sizes of 1–3 nm were attached quite uniformly on surfaces of 5–15 nm cubic Zn2SnO4 nanoparticles. The sensing layers fabricated by spin coating technique were measured towards various environmental gases and VOCs in dry ambient at 200–400 °C. Gas-sensing data showed that the Zn2SnO4-based sensor with the optimum Pt content of 2 wt% exhibited high H2 selectivity against to other environmental gases and VOCs with an excellent response of 1500.4 and a small response time of ∼3.4 s toward 10,000 ppm H2 at an optimal working temperature of 350 °C. Moreover, the PtOx-loaded Zn2SnO4 sensor presented low dependency of response on humidity, high stability and good reproducibility. The results were explained based on the effects of PtOx-Zn2SnO4 heterointerfaces on spillover mechanisms. Therefore, the flame-made PtOx-loaded Zn2SnO4 nanoparticles could be a highly promising candidate for practical H2-sensing applications.