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

Abstract

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 °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.