Rapid Hydrogen Detection with Low Temperature Realized by Regulating Chemisorbed Oxygen Species of Mesoporous Indium Tin Oxide Microsphere

Abstract

The hydrogen sensors have attracted great attention due to the widely application of hydrogen in many fields and its high risk. However, the low sensitivity, slow response-recovery, high working temperature and bad detection limit greatly hinder the application of these sensors. In this work, a series of indium tin oxides (ITOs) with enhanced hydrogen sensing performance were successfully synthesized by a "self-template" solvothermal method and followed calcination. At a low working temperature of 200 o C, 10.7 % In-doped SnO 2 (named as ITO-II) based sensor exhibits high sensitivity, excellent selectivity, great stability and ultra-fast dynamic process (response time and recovery time < 3 s). X-ray photoelectron spectroscopy and scanning Kelvin probe technique reveal the band structure and the regulated chemisorbed oxygen species of ITO-II. O 2  temperature-programmed desorption and H 2  temperature-programmed reduction analysis suggest that she excellent selectivity, high sensitivity and fast response-recovery should be attributed to the increased chemisorbed oxygen and the high intrinsic reactivity of SnO 2  toward hydrogen. The strategy of forming alkoxide precursors provides a new insight for the preparation of mesoporous ITO solid solution with good hydrogen sensing performance.

Keywords: Hydrogen, Gas sensor, solvothermal method, mesoporous ITO, chemisorbed oxygen