The synergistic sensitization strategy based on bimetallic AuPd-modified In2O3 nanospheres compounded on rGO for ppb-level toluene detection

Toluene is not only a prevalent indoor air pollutant but also a regulated chemical precursor in illicit drug synthesis. Therefore, developing a gas sensor capable of highly sensitive detection of trace toluene is critically important. In this study, rGO-In 2 O 3 -AuPd nanocomposites were synthesized through the hydrothermal growth of In 2 O 3 on rGO and the in-situ chemical reduction of Au and Pd precursors, achieving ppb-level detection of toluene. The crystalline phase, nanoscale morphology, and chemical states of the nanomaterials were systematically characterized and analyzed through characterization techniques such as XRD, SEM, TEM, and XPS. Gas-sensing experiments revealed that the rGO-In 2 O 3 -AuPd demonstrated superior gas-sensing performance to toluene, exhibiting a high response value (101.1) to 100 ppm toluene, which was 43.96 times that of pure In 2 O 3 . Additionally, comparative studies demonstrated that the gas-sensing performance of In 2 O 3 modified with AuPd bimetallic nanoparticles (NPs) surpassed that of In 2 O 3 modified with a single metal (Au or Pd). The synergistic sensitization strategy based on bimetallic AuPd-modified In 2 O 3 compounded on rGO effectively reduced the operating temperature while enhancing the sensitivity response. This study provides promising sensing materials and design concepts for developing low-power, high-sensitivity trace-level toluene sensors.