Exsolution of catalytic cobalt nanoparticles for metal oxide chemiresistive gas sensors with highly selective and stable acetone detection

Abstract

Acetone detection in exhaled breath is a useful and promising tool for the noninvasive diagnosis of diabetes. As human breath contains hundreds of different volatile organic compound gases with high humidity and low concentrations, sensors that can accurately detect acetone without cross-interference with water molecules and other gases should be developed. In this study, a new type of chemiresistive sensor that can solve existing problems was explored by introducing an exsolution method in which catalytic Co nanoparticles were uniformly exsolved on a ZnO surface with a unique socket-like structure. This sensor can sense acetone at the sub-ppm level with ultrahigh selectivity using exsolved Co nanoparticles, which completely removed potential interfering gases through catalytic oxidation. The developed sensor exhibited high immunity to humidity variations. Furthermore, it exhibited excellent thermal stability and long-term detection reliability at high temperatures owing to the strong metal-support interaction between the nanosocketed Co particles and parent ZnO oxide support.