Facile preparation of hierarchical structure based on p-type Co3O4 as toluene detecting sensor

Abstract Rational structure design of sensing materials plays a crucial part in fabricating high performance gas sensors. In this work, three Co3O4 samples with different morphologies, including Co3O4-C (Cube-shaped Co3O4), Co3O4-R (Rod-shaped Co3O4) and Co3O4-S (Sheet-shaped Co3O4), were synthesized through a hydrothermal route. Hierarchical structures-dependent gas-sensing properties were further investigated. The toluene sensing performance of Co3O4-S hierarchical structure-based sensor outperforms the other two ones. It exhibited higher sensitivity, faster response-recovery speed and better selectivity to toluene at the working temperature of 180 °C. In addition, the Co3O4-S-based gas sensor can maintain its sensitivity to toluene after one month, suggesting it good reliability. Preliminary functional tests for the detection of toxic analytes indicated it can be considered as a promising candidate for applications in detecting toluene.