Copper-Containing Films Obtained by the Simple Citrate Sol–Gel Route for NO2 Detection: Adsorption and Kinetic Study

Tatiana N Myasoedova,Tatiana A Moiseeva,Nina K Plugotarenko

doi:10.3390/chemosensors8030079

Tatiana N Myasoedova, Tatiana A Moiseeva + Show 1 more

Open Access

https://doi.org/10.3390/chemosensors8030079

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Journal: Chemosensors	Publication Date: Aug 30, 2020
Citations: 4	License type: CC BY 4.0

Affiliation: Southern Federal University

Abstract

The citrate sol–gel method was utilized for the fabrication of copper-containing films sensitive to NO2 gas. Effect of annealing temperature on the film phase composition, morphology, and sensor response was studied. X-ray diffraction reveals the formation of Cu2Cl(OH)3 phase at 250 °C and the CuO phase at 350 and 500 °C. It was found out that the films annealed at 250 °C and 350 °C showed the best sensor characteristics. The influence of thermal degradation on the probability of percolation effect in films and its connection to a decrease of gas sensitivity was studied. The kinetics of the NO2 gas adsorption on the film’s surface was described following the Elovich model. Activation energy estimated from the ln(S) vs. 1/T plots was 252 and 30 kJ/mol for the films annealed at 250 and 350 °C, respectively.

Highlights

Nitrogen oxides are formed in the atmosphere, both natural and by anthropogenic combustion of fossil fuels
It is evident that when producing gas-sensitive materials, it is necessary to increase and develop a surface adsorption center activity [16,17,18], which significantly depends on the technological conditions of manufacturing, i.e., type of precursors, reaction temperature, time, etc
Materials based on copper oxide have promising physicochemical properties for gas sensor applications [15,19,20] due to their capability to form nanostructures with a different particle’s shape, such as cubes, sheets, stars, flowers, and others [21,22,23]

Summary

Introduction

Nitrogen oxides are formed in the atmosphere, both natural and by anthropogenic combustion of fossil fuels. The main anthropogenic sources of nitrogen oxides entering the atmosphere are the combustion of all types of natural fuels (12 million tons/year), transport (8 million tons/year), and industry (1 million tons/year). The oxide semiconductor gas sensor attracted attention due to its high sensitivity, low cost, and simple fabrication [4]. Copper oxide (CuO) as p-type material has attracted significant attention in last decade for its possible application as gas sensors [5,6,7,8,9,10,11,12,13,14,15]. Materials based on copper oxide have promising physicochemical properties for gas sensor applications [15,19,20] due to their capability to form nanostructures with a different particle’s shape, such as cubes, sheets, stars, flowers, and others [21,22,23]

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