Sensitive and selective ozone sensor based on CuCo2O4 synthesized by a facile solution combustion method

In this study, p-type spinel CuCo2O4 nanomaterials with abundant oxygen vacancies were synthesized by a facile one-step solution combustion method, and their sensing characteristics have been investigated. The p-type CuCo2O4 sensor shows a high response of 11 to 1 ppm O3 and low responses (< 2) to various interference gases (100 ppm NH3, NO2, SO2, and 500 ppm ethanol, methanol and acetone) at 90 °C in dry air, indicating a superior selectivity. The sensor also possesses a wide O3 detection range from 10 to 3000 ppb and good repeatability. More importantly, the relative humidity (RH) could promote the electrical response to O3, and the response to 1 ppm O3 only deviates from 24 to 27 as the RH increases from 50% to 90%, benefitting for practical applications in ambient humid air atmospheres. The humidity enhanced response for p-type CuCo2O4 could be ascribed to the competition of hole carrier reduction, O2− active sites reduction and O3 decomposition promotion induced by the hydroxyl groups.