Synthesis and characterization of Ag NPs and Ag@Cr core–shell nanoparticles for sensing H₂S gas via plasma jet

High-performance gas sensor devices with core–shell structures can be obtained by optimizing the preparation conditions. This work describes the use of a plasma Jet to fabricate Ag@Cr NPs. The core and shell Ag@Cr nanoparticles (NPs) with core and shell structure were synthesized by using a plasma process, which involved the initial synthesis of Ag NPs and their subsequent mixing with chromium solution. Using different methods, which include HRTEM, XRD, and FESEM, Ag/Cr and Ag NPs have been characterized. The resulting particles have a spherical shape. The presence of elements is verified by Energy Dispersive X-ray analysis. According to data from ultraviolet–visible spectroscopy, the prepared materials exhibit a direct energy gap value between 2.06 and 3.05 eV. Under various operating temperatures, films have been examined for H₂S sensing. Differences in thin-film resistance to the gas sensing response that have been observed suggest either n-type or p-type conductivity. The resistance related to films (Ag, AgCr) increases in the case when Ag@Cr NPs as well as Ag NPs are present in a reducing gas, which indicates that the films are p-type. The prepared gas’s sensitizing qualities were assessed in relation to low H₂S concentrations. The impact of hierarchical electronic sensitization was discovered. When put to comparison with original Ag sensors, the peculiarity of chromium nanoparticles in Ag/Cr sensors significantly alters the gas sensing capabilities.