Palladium‐Loaded Hierarchical Flower‐like Tin Dioxide Structure as Chemosensor Exhibiting High Ethanol Response in Humid Conditions

Abstract

AbstractThe impact of humidity is a crucial factor in the sensing performance of a chemiresistive gas sensor. Therefore, strategies for developing sensors with a small humidity dependence are required. Herein, the volatile organic compound (VOC)‐sensing performance of palladium‐loaded hierarchical flower‐like tin dioxide structures (Pd/FL‐SnO2) under humid conditions is reported. To prepare the Pd/FL‐SnO2 heterostructures, FL‐SnO2 is first synthesized using a microwave‐assisted solvothermal method, followed by calcination, and then is loaded with Pd nanoparticles (NPs). VOC‐sensing studies are conducted in dry and wet air with relative humidities (RHs) between 25% and 98%. FL‐SnO2 and Pd/FL‐SnO2 exhibit an enhanced response toward ethanol in comparison with other VOCs, including acetone, benzene, methanol, m‐xylene, and toluene. However, FL‐SnO2 with Pd NPs has a substantially decreased optimal working temperature, from 340 to 140 °C, and an improved selectivity. Furthermore, the ethanol response of the Pd/FL‐SnO2 heterostructures is preserved under humid conditions, whereas the response of FL‐SnO2 is significantly affected by humidity. The response to 100 ppm of ethanol under 98% RH is 3.1 and 8.0 for neat FL‐SnO2 and 5% Pd/FL‐SnO2 heterostructure, respectively. The ethanol‐sensing performance enhancement under high humidity is attributed to the Pd/SnO2 heterointerface.