Preparation and Hydrogen-Sensitive Property of WO3/Graphene/Pd Ternary Composite

Abstract

Hydrogen (H2) is a renewable energy source that has the potential to reduce greenhouse gas emissions. However, H2 is also highly flammable and explosive, requiring sensitive and safe sensors for its detection. This work presents the synthesis and characterization of WO3/graphene binary and WO3/graphene/Pd (WG-Pd) ternary nanocomposites with varying graphene and Pd contents using the microwave-assisted hydrothermal method. The excellent catalytic efficacy of Pd nanoparticles facilitated the disintegration of hydrogen molecules into hydrogen atoms with heightened activity, consequently improving the gas-sensing properties of the material. Furthermore, the incorporation of graphene, possessing high conductivity, serves to augment the mobility of charge carriers within the ternary materials, thereby expediting the response/recovery rates of gas sensors. Both graphene and Pd nanoparticles, with work functions distinct from WO3, engender the formation of a heterojunction at the interface of these diverse materials. This enhances the efficacy of electron–hole pair separation and further amplifies the gas-sensing performance of the ternary materials. Consequently, the WG-Pd based sensors exhibited the best gas-sensing performance when compared to anther materials, such as a wide range of hydrogen concentrations (0.05–4 vol.%), a short response time and a good selectivity below 100 °C, even at room temperature. This result indicates that WG-Pd ternary materials are a promising room-temperature hydrogen-sensing materials for H2 detection.