Fabrication of a selective 4-amino phenol sensor based on H-ZSM-5 zeolites deposited silver electrodes

Abstract

H-ZSM-5 zeolite is an inorganic material with large surface area and well-defined internal structure with porous uniform cages, cavities or channels. In this study, H-ZSM-5 was synthesised by calcination of the NH₄-form at 500 °C for 3 h in air flow. This protonated H-ZSM-5 has been characterized in detail, which includes its optical, structural, morphological, and elemental properties by various conventional methods. For probable chemical sensor development, H-ZSM-5 was deposited on a silver electrode (AgE, surface area, 0.0216 cm²) to fabricate a sensor with a fast response towards selective 4-amino phenol (4-AMP) in the liquid phase. The sensor exhibited good sensitivity and long-term stability and enhanced electrochemical responses. The calibration plot was linear (r² = 0.9979) over the 0.1 nM to 1.0 mM 4-AMP concentration ranges. The sensitivity was ∼2.085 μA cm⁻² nM⁻¹ and the detection limit was 0.02 nM (at a signal-to-noise ratio (SNR) of 3). By employing CV and EIS techniques, it was unveiled that the sensor is not well-operative in the absence of air. This shows a promising future for sensitive sensor development using mesoporous H-ZSM-5 by I–V methods for applications in the detection of hazardous and carcinogenic phenolic compounds in environmental and health care fields.