Bacterial cellulose templated p-Co3O4/n-ZnO nanocomposite with excellent VOCs response performance

In this work, p-type Co3O4 decorated n-type ZnO (Co3O4/ZnO) nanocomposite was designed with the assistance of bacterial cellulose template. Phase composition, morphology and element distribution were investigated by XRD, SEM, HRTEM, EDS mapping and XPS. Volatile organic compounds (VOCs) sensing measurements indicated a noticeable improvement of response and decrease of working temperature for Co3O4/ZnO sensor, in comparison with pure ZnO, i.e., the response towards 100 ppm acetone was 63.7 (at a low working temperature of 180 °C), which was 26 times higher than pure ZnO (response of 2.3 at 240 °C). Excellent VOCs response characteristics could be ascribed to increased surface oxygen vacancy concentration (revealed by defect characterizations), catalytic activity of Co3O4 and the special p-n heterojunction structure, and bacterial cellulose provides a facile template for designing diverse functional heterojunctions for VOCs detection and other applications.