Dual-selective detection of CO and CH4 based on hierarchical porous In2O3 nanoflowers with Pd modification

The timely and effective detection of CO and CH4 is critical as the explosion and poisoning of them can bring serious potential risks to coal mining. In this study, combining metal oxide semiconductors with noble metals offers a promising route to achieve this target. Hierarchical porous Pd modified In2O3 nanoflowers were prepared via two-step hydrothermal method and exhibited dual detection of CO and CH4 at different temperatures. The material has been characterized by a number of advanced techniques and the results indicate that Pd modified In2O3 are hierarchical porous nanoflowers structure consisting of pores of approximately 1.8 nm in size. The sensing properties results show that the Pd modified In2O3 based sensor exhibits temperature-dependent dual selectivity detection of CO at 280 °C and CH4 at 340 °C. In addition, the Pd modified In2O3 sensor display higher sensing response of CO (5.824 for 100 ppm) and CH4 (1.162 for 1000 ppm), fast response and recovery time, as well as good repeatability, which demonstrating the great potential for practical application. Such good gas-sensing performance are mainly attributed to the unique flower-like structure, the presence of porosity on the sample surface, and the catalytic effect of Pd.