Photochemical fabrication of defect-abundant Pd/SnO2 with promoted performance for dioctyl phthalate gas sensing

The development of a selective and fast response gas sensor for dioctyl phthalate (DOP) has been attracting considerable attention for the early warning of electrical fires. In this study, photodeposition was applied to fabricate highly dispersed Pd/SnO2 with abundant defects. The obtained 5%Pd/SnO2 has more Sn2+ species and oxygen vacancies than SnO2, which may be due to the reduction of photogenerated electrons. 5%Pd/SnO2 exhibited the best comprehensive performance in response value and response and recovery time for DOP sensing among different Pd loadings. The response to 5 ppm of DOP is 3.58 at 240 degrees C, which is much higher than 1.03 for SnO2, due to the abundant oxygen vacancies and Sn2+ defects of the material. Besides, the material exhibited good selectivity, stability, and a linear response to different concentrations of DOP. The 5%Pd/SnO2 sensor also responded much faster than conventional smoke detectors for the overheated PVC cable.