The effect of Co and In combinational or individual doping on the structural, optical and selective sensing properties of ZnO nanoparticles

Maswanganye, Mpho William; Rammutla, K.E.; Mosuang, Thuto; Mwakikunga, Bonex W.

doi:10.1016/j.snb.2017.02.039

Cited by 42 publications

(22 citation statements)

References 39 publications

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“…Maswangwane et al . 49 also found that both the undoped and In-doped ZnO displayed optimal response values at a RH level of 50% since further increase in RH levels up to 100% led to significant drop in response values of these sensors. The observed drop in sensor performance with increasing humidity levels in this work therefore arises from competition between the water vapor molecules and the NH 3 molecules for the surface reaction sites, thereby limiting oxygen adsorption 13 .…”

Section: Resultsmentioning

confidence: 71%

A highly responsive NH3 sensor based on Pd-loaded ZnO nanoparticles prepared via a chemical precipitation approach

Mhlongo

Motaung

Cummings

et al. 2019

Sci Rep

103

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The gas-detecting ability of nanostructured ZnO has led to significant attention being paid to the development of a unique and effective approach to its synthesis. However, its poor sensitivity, cross-sensitivity to humidity, long response/recovery times and poor selectivity hinder its practical use in environmental and health monitoring. In this context, the addition of noble metals, as dopants or catalysts to modify the ZnO surface has been examined to enhance its sensing performance. Herein, we report preparation of Pd-loaded ZnO nanoparticles via a chemical precipitation approach. Various Pd loadings were employed to produce surface-modified ZnO nanostructure sensors, and their resulting NH 3 sensing capabilities both in dry and humid environments were investigated. Through a comparative gas sensing study between the pure and Pd-loaded ZnO sensors upon exposure to NH 3 at an optimal operating temperature of 350 °C, the Pd-loaded ZnO sensors were found to exhibit enhanced sensor responses and fast response/recovery times. The influence of Pd loading and its successful incorporation into ZnO nanostructure was examined by X-ray diffraction, high resolution-transmission electron microscopy, and X-ray photoelectron spectroscopy. XPS studies demonstrated that in all samples, Pd existed in two chemical states, namely Pd° and Pd 2+ . The possible sensing mechanism related to NH 3 gas is also discussed in detail.

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Section: Resultsmentioning

confidence: 71%

A highly responsive NH3 sensor based on Pd-loaded ZnO nanoparticles prepared via a chemical precipitation approach

Mhlongo

Motaung

Cummings

et al. 2019

Sci Rep

103

View full text Add to dashboard Cite

show abstract

“…Among them, metal oxide semiconductor materials such as ZnO, TiO 2 , CuO, and Al 2 O 3 are widely used for sensor development due to their simple fabrication, high sensing response, good operational stability, low cost, and good portability [12,13,14,15]. Among them, ZnO has become widely studied as a nano-sensing material because it is plentiful and has controllable surface morphology, wide resistivity range, good chemical stability, and thermal stability [15,16].…”

Section: Introductionmentioning

confidence: 99%

Effects of pH on High-Performance ZnO Resistive Humidity Sensors Using One-Step Synthesis

Zhang

et al. 2019

Sensors

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In this paper, we prepared a high-performance zinc oxide (ZnO) humidity sensor in an alkaline environment using one-step hydrothermal method. Experiments showed that the pH value of the precursor solution affects the performance of ZnO humidity sensors. There are abundant hydroxyl group and oxygen vacancies on the surface of ZnO with a precursor pH value of 10. Abundant hydroxyl groups on the surface of ZnO can adsorb a large number of water molecules and rich oxygen vacancies can accelerate the decomposition of water molecules, thus increasing the number of conductive ions (H3O+) and further improving the performance of the sensor. So, such a ZnO humidity sensor exhibited high sensitivity (14,415), good linearity, small hysteresis (0.9%), fast response/recovery time (31/15 s) in the range from 11% to 95% relative humidity (RH). Moreover, the ZnO-2 humidity sensor has good repeatability and can be effectively used for a long time. This study provides a new idea for the development of low-cost, high-performance and reusable ZnO resistive humidity sensors.

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“…In gas sensors, selectivity is one of the key parameter more especially gas sensor for disease detection to ensure correct diagnosis and avoid false positive results. To perform the selectivity test, we used the selectivity (σ) equation [39]: Where R , gas is the gas of interest and + R gas1…”

Section: Gas Sensing Properties Of Wo 3 Sensorsmentioning

confidence: 99%

Effect of varying ethanol and water compositions on the acetone sensing properties of WO₃ for application in diabetes mellitus monitoring

Saasa

Lemmer²,

Malwela

et al. 2020

Mater. Res. Express

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Tungsten oxide based gas sensors have attracted a lot of attention in breath acetone analysis due to their potential in clinical diagnosis of diabetes. The major problem with this material in sensor application has been remarkable response to all gases but low selectivity to specific gases. Herein, we report the gas sensing performance of WO 3 materials which were synthesized by varying water and ethanol ratios using a facile solvothermal method for acetone detection. The gas sensing properties of as-prepared WO 3 were tested on acetone C 7 H 8 , NO 2 , NH 3 , H 2 S and CH 4 under relative humidity. X-ray diffraction patterns show that as-prepared WO 3 samples are mainly composed of monoclinic WO 3 , a phase having relatively high selectivity to acetone. The as-prepared WO 3 sensors produced using 51:49 ratio of water: ethanol show an increase in acetone response as the acetone concentration increases and a decrease in acetone response as the relative humidity increases. The sensor responded to a very low acetone concentration ranging from 0.5 to 4.5 ppm which is normally found in human breath. Furthermore, the sensor exhibited high sensitivity and selectivity to low ppm of acetone at 100°C. On contrary, the sensor showed significantly lower response to other gases tested.

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The effect of Co and In combinational or individual doping on the structural, optical and selective sensing properties of ZnO nanoparticles

Cited by 42 publications

References 39 publications

A highly responsive NH3 sensor based on Pd-loaded ZnO nanoparticles prepared via a chemical precipitation approach

A highly responsive NH3 sensor based on Pd-loaded ZnO nanoparticles prepared via a chemical precipitation approach

Effects of pH on High-Performance ZnO Resistive Humidity Sensors Using One-Step Synthesis

Effect of varying ethanol and water compositions on the acetone sensing properties of WO₃ for application in diabetes mellitus monitoring

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The effect of Co and In combinational or individual doping on the structural, optical and selective sensing properties of ZnO nanoparticles

Cited by 42 publications

References 39 publications

A highly responsive NH3 sensor based on Pd-loaded ZnO nanoparticles prepared via a chemical precipitation approach

A highly responsive NH3 sensor based on Pd-loaded ZnO nanoparticles prepared via a chemical precipitation approach

Effects of pH on High-Performance ZnO Resistive Humidity Sensors Using One-Step Synthesis

Effect of varying ethanol and water compositions on the acetone sensing properties of WO3 for application in diabetes mellitus monitoring

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Effect of varying ethanol and water compositions on the acetone sensing properties of WO₃ for application in diabetes mellitus monitoring