Efficient room temperature detection of H2 gas by novel ZnFe2O4–Pd decorated rGO nanocomposite

Abstract

A rapid and efficient microwave assisted synthetic route was adopted for the synthesis of ZnFe2O4–Pd decorated rGO nanocomposite. The combination of tunable electrical property of rGO and excellent sensing capability of both Pd and ZnFe2O4 was taken in to account towards the high performance hydrogen gas sensing. The structural confirmation of the designed nanocomposite was carried out by various sophisticated characterization techniques like Fourier transform infrared spectroscopy, Raman spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, Transmission electron microscopy and N2 adsorption-desorption analysis. The Transmission electron microscopy analysis revealed the presence of both ZnFe2O4 and Pd nanoparticles distributed uniformly on the rGO surface and the average particle sizes of ZnFe2O4 and Pd were found to be 7–9 and 3–5 nm respectively. The crystalline nature of the nanocomposite was confirmed from the selected area electron diffraction pattern. The synthesized nanocomposite showed high sensitivity towards a wide range of H2 gas concentrations (50-1000 ppm) (3.36 %-29.13 %). The effect of temperature (25–100 °C) on the sensing response of the designed nanocomposite was investigated. The sensor showed high response (11.43%) towards 200 ppm of H2 gas selectively with fast response (18 s) and recovery time (39 s) at room temperature. The enhanced sensing behavior can be attributed to the combined effects of high surface area and electrical conductivity of rGO with high charge carrier mobility and high sensing ability of both ZnFe2O4 and Pd nanoparticles.