Improving carrier transport and catalytic oxidation of Bi2O3/Co3O4 hybrid structures to enhance gas sensing selectivity and response toward n-butanol gas

Abstract

N-butanol is a widely used and multifunctional raw material, but is harmful to the environment and human health. Developing gas sensing materials with high selectivity toward n-butanol is the foundation and crux to achieve n-butanol precise detection. Herein, Bi2O3/Co3O4 hybrid structures have been constructed by a feasible two-step strategy and employed as gas sensing materials. The gas sensor based on Bi2O3/Co3O4 composites treated at 400 °C (BCO-400) presents a high selectivity, a superior stability/reliability, a well humidity resistance and a low detection limit of 1 ppm toward n-butanol at a relatively low operating temperature of 130 °C. The response and response/recovery time of BCO-400 to 1 ppm n-butanol is 14.9 % and 51 s/53 s, respectively. In the hybrid structures, p-type Bi2O3 semiconductor as a catalyst promotes the catalytic selectivity of Bi2O3/Co3O4 toward n-butanol gas while the semiconductor Co3O4 significantly improves carrier transport and further decreases baseline resistance in air of hybrid structures, which collaboratively brings about the improved gas sensing performance to n-butanol. This work provides a preferable strategy for bismuth based semiconductor materials in the field of the low temperature volatile organic gas detection.