Research and fabrication of NiO/PPy hybrid structural materials with high gas sensitivity to ammonia (NH3)

16/05/2022

The research group of Dr. Ho Truong Giang and his colleagues at the Institute of Materials Science have studied and fabricated a hybrid material film between a conductive polymer (polypyrrole) and metal oxide nanoparticles (NiO) by polymerization from the vapor phase, using catalyst FeCl3 salt with different concentrations to control the ratio of NiO and PPy combinations. This is the result of the project "Research, design and manufacture sensors to build a system of equipment to measure exhaust gas concentration and control fuel combustion" code KC05.13/16-20 under the Program "Research and application of energy technology" KC05/2016-2020.

Recently, the direction of research on inorganic-organic hybrid materials is of great interest in many fields such as sensor components, storage batteries, LEDs, and catalysts. Gas sensors based on inorganic (metal oxide) and organic (conducting polymer) hybrid materials offer the possibility to develop devices that operate at room temperature, with high selectivity and sensitivity to target gases. On the other hand, although there are many publications on inorganic/organic hybrid materials for gas sensitization, understanding the mechanism or existence of the hybrid structure is still an issue on which researchers need to have further clarification evidence.

The research group of Dr. Ho Truong Giang and his colleagues fabricated films of hybrid materials between conducting polymers (polypyrrole) and metal oxide nanoparticles (NiO) by polymerization from the vapor phase using FeCl3 salt as catalyst with different concentrations to control the combination ratio between NiO and PPy. The survey results include X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared absorption spectroscopy (FTIR), Raman scattering spectroscopy, and Gas sensitive characterization for the samples confirmed the formation of hybrid structure between NiO and PPy.The NiO/PPy film samples exhibit high sensitivity and selectivity to NH gas at room temperature (25oC), with the maximum response value reaching S = 246.6 % at 350 ppm.

(a) SEM image of NiO/PPy, (b) illustrates how the NiO/PPy hybrid contact determines the gas sensitivity characteristic, (c) the resistance of the samples responding to NH3 gas concentrations, (d) the response depends on the concentration of NH3 gas, and (e) the gas sensitivity depends on the ratio of the combination of NiO and Ppy

This result of the research team has been published in the prestigious international journal: Sensors and Actuators B (IF = 7.46), Volume 340, 1 August 2021, 129986, “High NH3 sensing performance of NiO/PPy hybrid nanostructures” .

Translated by Phuong Ha
Link to Vietnamese version