Synthesis and characterization of SnO₂-modified ZSM-5 zeolite for hydrogen gas sensing

In the present work, pure and SnO₂ modified ZSM-5 zeolites were successfully prepared using hydrothermal method. Structural, morphological, surface compositions and vibrational properties of the synthesized samples were characterized by XRD, HRTEM, FE-SEM, EDS, XPS, and FT-IR. HRTEM analysis through SAED patterns showed that pure and SnO₂ modified ZSM-5 have well-defined nanocrystalline structure. SnO₂ nanoparticles, approximately 5 nm in size, were highly dispersed and homogenously distributed throughout the ZSM-5 zeolite. XPS surface composition analysis confirmed Sn in its +4 oxidation state, indicating that ZSM-5 successfully incorporated the SnO₂ nanoparticles. The SnO₂ modified ZSM-5 zeolite chemiresistive sensitivity towards different concentrations of H₂ gas (500–10,000 ppm) was investigated. The sensor exhibited reasonable performance with excellent stability and repeatability. Moreover, the transient and steady state characteristics of the sensor's experimental response to hydrogen was found to be consistent with the Langmuir adsorption model in evaluating the adsorption/desorption behavior of analytes (i.e., H₂ adsorbate) on the sensor's active layer, under different concentrations.