Enhanced sensing performance of catalytic combustion methane sensor by using Pd nanorod/γ-Al2O3

Novel metal palladium was loaded on γ-Al2O3 using decompression distillation, ultrasonic impregnation, and isometric impregnation. Of these loading methods, isometric impregnation was examined to be the best method for preparing high-performance Pd/Al2O3 catalysts. The observation with transmission electron microscopy demonstrated that Pd nanorods were formed on γ-Al2O3 for the samples preparing with isometric impregnation. The correlation of the morphology of Pd with the loading time was also investigated: Pd catalysts loaded for 2 and 6 h had the almost same nanorod morphology and relatively uniform size. Nitrogen adsorption and desorption isotherms indicate that Pd nanorods increased the BET-specific surface area of Pd/γ-Al2O3. The catalytic combustion gas sensor prepared using Pd/γ-Al2O3 via isometric impregnation exhibited high sensitivity to methane as well as fast response and recovery properties.