ENHANCED DIELECTRIC AND CONDUCTIVE PROPERTIES OFZEOLITE ZSM-5 PREPARED VIA MICROWAVE-ASSISTEDHYDROTHERMAL METHOD

Abstract

This study investigates the electrical response of Zeolite ZSM-5 synthesized using a microwave-assisted hydrothermal method. Microwave heating significantly reduced crystallization time from 24–48 hours in conventional synthesis to just 2–3 hours, while also enhancing crystallinity and phase purity. X-ray diffraction (XRD) confirmed the successful formation of the MFI-type framework. Electrical characterization, performed using impedance spectroscopy in the frequency range of 40 Hz–10 MHz, revealed a strong frequency dependence of dielectric properties. The dielectric constant (ε′) was higher at low frequencies due to Maxwell–Wagner interfacial polarization and decreased with increasing frequency, while dielectric loss (tan δ) stabilized at higher frequencies. AC conductivity (σ_ac) followed Jonscher’s power law, indicating hopping conduction as the dominant mechanism. The conduction process was mainly ionic, attributed to the migration of chargecompensating cations in the zeolite channels, with a minor electronic contribution at higher frequencies. The Si/Al ratio played a crucial role in tuning the electrical properties: samples with a lower Si/Al ratio (30) exhibited higher dielectric constant and ionic conductivity, whereas those with a higher ratio (70) showed improved dielectric stability. Microwavesynthesized samples consistently outperformed their conventionally prepared counterparts, making this approach highly effective for tailoring electrical properties of ZSM-5 for applications in solid-state ionics, dielectric devices, and sensors.