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Tripathi M, Deokar G, Casanova-Chafer J, Jin J, Sierra-Castillo A, Ogilvie SP, Lee F, Iyengar SA, Biswas A, Haye E, Genovese A, Llobet E, Colomer JF, Jurewicz I, Gadhamshetty V, Ajayan PM, Schwingenschlögl U, Costa PMFJ, Dalton AB. Vertical heterostructure of graphite-MoS 2 for gas sensing. NANOSCALE HORIZONS 2024; 9:1330-1340. [PMID: 38808602 DOI: 10.1039/d4nh00049h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2024]
Abstract
2D materials, given their form-factor, high surface-to-volume ratio, and chemical functionality have immense use in sensor design. Engineering 2D heterostructures can result in robust combinations of desirable properties but sensor design methodologies require careful considerations about material properties and orientation to maximize sensor response. This study introduces a sensor approach that combines the excellent electrical transport and transduction properties of graphite film with chemical reactivity derived from the edge sites of semiconducting molybdenum disulfide (MoS2) through a two-step chemical vapour deposition method. The resulting vertical heterostructure shows potential for high-performance hybrid chemiresistors for gas sensing. This architecture offers active sensing edge sites across the MoS2 flakes. We detail the growth of vertically oriented MoS2 over a nanoscale graphite film (NGF) cross-section, enhancing the adsorption of analytes such as NO2, NH3, and water vapor. Raman spectroscopy, density functional theory calculations and scanning probe methods elucidate the influence of chemical doping by distinguishing the role of MoS2 edge sites relative to the basal plane. High-resolution imaging techniques confirm the controlled growth of highly crystalline hybrid structures. The MoS2/NGF hybrid structure exhibits exceptional chemiresistive responses at both room and elevated temperatures compared to bare graphitic layers. Quantitative analysis reveals that the sensitivity of this hybrid sensor surpasses other 2D material hybrids, particularly in parts per billion concentrations.
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Affiliation(s)
- M Tripathi
- Department of Physics and Astronomy, University of Sussex, Brighton BN1 9RH, UK.
| | - G Deokar
- King Abdullah University of Science and Technology (KAUST), Physical Science and Engineering Division, Thuwal, 23955 - 6900, Saudi Arabia
| | - J Casanova-Chafer
- Universitat Rovira i Virgili, MINOS, Avda. Països Catalans, 26, 43007 Tarragona, Spain
| | - J Jin
- King Abdullah University of Science and Technology (KAUST), Physical Science and Engineering Division, Thuwal, 23955 - 6900, Saudi Arabia
| | - A Sierra-Castillo
- Research Group on Carbon Nanostructures (CARBONNAGe), University of Namur, 5000 Namur, Belgium
| | - S P Ogilvie
- Department of Physics and Astronomy, University of Sussex, Brighton BN1 9RH, UK.
| | - F Lee
- Department of Physics and Astronomy, University of Sussex, Brighton BN1 9RH, UK.
- International Institute for Nanocomposites Manufacturing (IINM), WMG, University of Warwick, Coventry CV47AL, UK
| | - S A Iyengar
- Department of Materials Science and NanoEngineering, Rice University, Houston, Texas, 77005, USA
| | - A Biswas
- Department of Materials Science and NanoEngineering, Rice University, Houston, Texas, 77005, USA
| | - E Haye
- Laboratoire d'Analyse par Réactions Nucléaires (LARN), Namur Institute of Structured Matter (NISM), University of Namur, 61 Rue de Bruxelles, 5000 Namur, Belgium
| | - A Genovese
- King Abdullah University of Science and Technology, Core Labs, Thuwal, 23955-6900, Saudi Arabia
| | - E Llobet
- Universitat Rovira i Virgili, MINOS, Avda. Països Catalans, 26, 43007 Tarragona, Spain
| | - J-F Colomer
- Research Group on Carbon Nanostructures (CARBONNAGe), University of Namur, 5000 Namur, Belgium
| | - I Jurewicz
- Department of Physics, Faculty of Engineering & Physical Sciences, University of Surrey, Guildford GU2 7XH, UK
| | - V Gadhamshetty
- Department of Civil and Environmental Engineering, and 2D-Materials for Biofilm Engineering, Science, and Technology Center, South Dakota School of Mines and Technology, Rapid City, SD, 57701, USA.
| | - P M Ajayan
- Department of Materials Science and NanoEngineering, Rice University, Houston, Texas, 77005, USA
| | - Udo Schwingenschlögl
- King Abdullah University of Science and Technology (KAUST), Physical Science and Engineering Division, Thuwal, 23955 - 6900, Saudi Arabia
| | - Pedro M F J Costa
- King Abdullah University of Science and Technology (KAUST), Physical Science and Engineering Division, Thuwal, 23955 - 6900, Saudi Arabia
| | - A B Dalton
- Department of Physics and Astronomy, University of Sussex, Brighton BN1 9RH, UK.
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2
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Zhao F, Li Z, Fu Y, Wang Q. Gas-Sensitive Characteristics of Graphene Composite Tungsten Disulfide to Ammonia. SENSORS (BASEL, SWITZERLAND) 2022; 22:8672. [PMID: 36433267 PMCID: PMC9696837 DOI: 10.3390/s22228672] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Revised: 10/29/2022] [Accepted: 11/06/2022] [Indexed: 06/16/2023]
Abstract
Two-dimensional materials have outstanding application prospects in gas sensing. By constructing composite structures of various gas-sensitive materials, more-efficient and sensitive gas sensors can be further developed. After graphene is compounded with WS2, the composite material can improve the gas detection performance. In this work, the adsorption energy and the electronic properties of a graphene/WS2 structure were calculated by first-principles before and after adsorption of NH3. The calculation results indicate that the bandgap of the material was appreciably reduced after NH3 was adsorbed. In addition, a graphene/WS2 gas sensor was prepared. The response of the sensor to NH3 at a concentration of 100 ppm was 2.42% and 1.73% at 30 °C and 60 °C, respectively. Combining simulation with experiment, it is feasible to use graphene composite WS2 to detect NH3, which provides a new idea for applications of graphene and other composite materials in gas sensing.
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Affiliation(s)
- Fei Zhao
- Institute of Electrical and Information Engineering, Zhenjiang College, Zhenjiang 212100, China
- Zhenjiang Key Laboratory of Advanced Sensing Materials and Devices, School of Mechanical Engineering, Jiangsu University, Zhenjiang 212013, China
| | - Zhongxue Li
- Zhenjiang Key Laboratory of Advanced Sensing Materials and Devices, School of Mechanical Engineering, Jiangsu University, Zhenjiang 212013, China
| | - Yongzhong Fu
- Zhenjiang Key Laboratory of Advanced Sensing Materials and Devices, School of Mechanical Engineering, Jiangsu University, Zhenjiang 212013, China
| | - Quan Wang
- Zhenjiang Key Laboratory of Advanced Sensing Materials and Devices, School of Mechanical Engineering, Jiangsu University, Zhenjiang 212013, China
- State Key Laboratory of Transducer Technology, Chinese Academy of Sciences, Shanghai 200050, China
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Ultra-Sensitive Photo-Induced Hydrogen Gas Sensor Based on Two-Dimensional CeO 2-Pd-PDA/rGO Heterojunction Nanocomposite. NANOMATERIALS 2022; 12:nano12101628. [PMID: 35630850 PMCID: PMC9147198 DOI: 10.3390/nano12101628] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Accepted: 05/06/2022] [Indexed: 11/17/2022]
Abstract
A two-dimensional (2D) CeO2-Pd-PDA/rGO heterojunction nanocomposite has been synthesised via an environmentally friendly, energy efficient, and facile wet chemical procedure and examined for hydrogen (H2) gas sensing application for the first time. The H2 gas sensing performance of the developed conductometric sensor has been extensively investigated under different operational conditions, including working temperature up to 200 °C, UV illumination, H2 concentrations from 50–6000 ppm, and relative humidity up to 30% RH. The developed ceria-based nanocomposite sensor was functional at a relatively low working temperature (100 °C), and its sensing properties were improved under UV illumination (365 nm). The sensor’s response towards 6000 ppm H2 was drastically enhanced in a humid environment (15% RH), from 172% to 416%. Under optimised conditions, this highly sensitive and selective H2 sensor enabled the detection of H2 molecules down to 50 ppm experimentally. The sensing enhancement mechanisms of the developed sensor were explained in detail. The available 4f electrons and oxygen vacancies on the ceria surface make it a promising material for H2 sensing applications. Moreover, based on the material characterisation results, highly reactive oxidant species on the sensor surface formed the electron–hole pairs, facilitated oxygen mobility, and enhanced the H2 sensing performance.
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4
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Comparative Analysis of Derivative Parameters of Chemoresistive Sensor Signals for Gas Concentration Estimation. CHEMOSENSORS 2022. [DOI: 10.3390/chemosensors10040126] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/10/2022]
Abstract
Signals from resistive gas sensors based on zirconium dioxide and silicon–carbon films have been extensively investigated to estimate gas concentration. In this study, the change in the normalized resistance of the sensor’s response under NO2 exposure is shown and the analysis of the first and second derivatives of the response curves were carried out. A signal-processing scheme, reducing the effect of noise and signal drift, is proposed. The extreme of the second derivative of the sensor response, the initial reaction rate, and the slope of the curve of the approximating line in the coordinates of the Elovich equation are proposed as calibration dependencies. The calibration curves built from the values of the maximum second derivative turned out to be the most stable, with the lowest relative error in estimating gas concentration compared to the traditional fixed-time point method.
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Two-Dimensional Dy2O3-Pd-PDA/rGO Heterojunction Nanocomposite: Synergistic Effects of Hybridisation, UV Illumination and Relative Humidity on Hydrogen Gas Sensing. CHEMOSENSORS 2022. [DOI: 10.3390/chemosensors10020078] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
A two-dimensional (2D) Dy2O3-Pd-PDA/rGO heterojunction nanocomposite has been synthesised and tested for hydrogen (H2) gas sensing under various functioning conditions, including different H2 concentrations (50 ppm up to 6000 ppm), relative humidity (up to 25 %RH) and working temperature (up to 200 °C). The material characterisation of Dy2O3-Pd-PDA/rGO nanocomposite performed using various techniques confirms uniform distribution of Pd NPs and 2D Dy2O3 nanostructures on multi-layered porous structure of PDA/rGO nanosheets (NSs) while forming a nanocomposite. Moreover, fundamental hydrogen sensing mechanisms, including the effect of UV illumination and relative humidity (%RH), are investigated. It is observed that the sensing performance is improved as the operating temperature increases from room temperature (RT = 30 °C) to the optimum temperature of 150 °C. The humidity effect investigation revealed a drastic enhancement in sensing parameters as the %RH increased up to 20%. The highest response was found to be 145.2% towards 5000 ppm H2 at 150 °C and 20 %RH under UV illumination (365 nm). This work offers a highly sensitive and selective hydrogen sensor based on a novel 2D nanocomposite using an environmentally friendly and energy-saving synthesis approach, enabling us to detect hydrogen molecules experimentally down to 50 ppm.
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Zhang F, Lin Q, Han F, Wang Z, Tian B, Zhao L, Dong T, Jiang Z. A flexible and wearable NO 2 gas detection and early warning device based on a spraying process and an interdigital electrode at room temperature. MICROSYSTEMS & NANOENGINEERING 2022; 8:40. [PMID: 35498341 PMCID: PMC9005537 DOI: 10.1038/s41378-022-00369-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Revised: 12/28/2021] [Accepted: 02/07/2022] [Indexed: 05/07/2023]
Abstract
Flexible sensors used to detect NO2 gas generally have problems such as poor repeatability, high operating temperature, poor selectivity, and small detection range. In this work, a new spraying platform with a simple structure, low cost, and good film-forming consistency was designed and built to make a sensitive film (rGO/SnO2) for NO2 gas sensors. The relationship between the solid content of rGO and SnO2 nanoparticles, annealing temperature, and sensor performance was studied. The results show that the interdigital electrode-sensitive film formed by spraying 0.25 ml of a 0.4 wt% rGO/SnO2 mixture and annealing at 250 °C exhibited the best comprehensive performance for NO2 detection. The sensor's response value for 100 ppm NO2 gas was 0.2640 at room temperature (25 °C), and the response time and recovery time were 412.4 s and 587.3 s, respectively. In the range of 20-100 ppm, the relationship between the response and NO2 concentration was linear, and the correlation coefficient was 0.9851. In addition, a soft-monitoring node module with an overlimit warning function for NO2 gas was designed and manufactured based on flexible electronics. Finally, the flexible sensor and node module were embedded into woven fabric that could be used to make a mask or a watch that could detect NO2 gas, realizing the practical application of flexible NO2 gas sensors in the field of wearable electronics.
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Affiliation(s)
- Fuzheng Zhang
- State Key Laboratory for Mechanical Manufacturing Systems Engineering, Xi’an Jiaotong University, 710049 Xi’an, China
| | - Qijing Lin
- State Key Laboratory for Mechanical Manufacturing Systems Engineering, Xi’an Jiaotong University, 710049 Xi’an, China
- Chongqing Key Laboratory of Micro-Nano Systems and Intelligent Sensing, Chongqing Academician Workstation, Chongqing 2011 Collaborative Innovation Center of Micro/Nano Sensing and Intelligent Ecological Internet of Things, Chongqing Technology and Business University, 400067 Chongqing, China
| | - Feng Han
- State Key Laboratory for Mechanical Manufacturing Systems Engineering, Xi’an Jiaotong University, 710049 Xi’an, China
| | - Zuowei Wang
- State Key Laboratory for Mechanical Manufacturing Systems Engineering, Xi’an Jiaotong University, 710049 Xi’an, China
| | - Bian Tian
- State Key Laboratory for Mechanical Manufacturing Systems Engineering, Xi’an Jiaotong University, 710049 Xi’an, China
| | - Libo Zhao
- State Key Laboratory for Mechanical Manufacturing Systems Engineering, Xi’an Jiaotong University, 710049 Xi’an, China
| | - Tao Dong
- Chongqing Key Laboratory of Micro-Nano Systems and Intelligent Sensing, Chongqing Academician Workstation, Chongqing 2011 Collaborative Innovation Center of Micro/Nano Sensing and Intelligent Ecological Internet of Things, Chongqing Technology and Business University, 400067 Chongqing, China
- Department of Microsystems, Faculty of Technology, Natural Sciences and Maritime Sciences, University of South-Eastern Norway (USN), Raveien 215, 3184 Borre, Norway
| | - Zhuangde Jiang
- State Key Laboratory for Mechanical Manufacturing Systems Engineering, Xi’an Jiaotong University, 710049 Xi’an, China
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One-Dimensional Nanomaterials in Resistive Gas Sensor: From Material Design to Application. CHEMOSENSORS 2021. [DOI: 10.3390/chemosensors9080198] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
With a series of widespread applications, resistive gas sensors are considered to be promising candidates for gas detection, benefiting from their small size, ease-of-fabrication, low power consumption and outstanding maintenance properties. One-dimensional (1-D) nanomaterials, which have large specific surface areas, abundant exposed active sites and high length-to-diameter ratios, enable fast charge transfers and gas-sensitive reactions. They can also significantly enhance the sensitivity and response speed of resistive gas sensors. The features and sensing mechanism of current resistive gas sensors and the potential advantages of 1-D nanomaterials in resistive gas sensors are firstly reviewed. This review systematically summarizes the design and optimization strategies of 1-D nanomaterials for high-performance resistive gas sensors, including doping, heterostructures and composites. Based on the monitoring requirements of various characteristic gases, the available applications of this type of gas sensors are also classified and reviewed in the three categories of environment, safety and health. The direction and priorities for the future development of resistive gas sensors are laid out.
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8
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Chen X, Jin W. Effective and Robust Parameter Identification Procedure of a Two-Site Langmuir Kinetics Model for a Gas Sensor Process. ACS Sens 2020; 5:2408-2414. [PMID: 32854509 DOI: 10.1021/acssensors.0c00442] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Gas sensors have received plenty of attention due to various applications, and the methods to model the kinetic processes and estimate the corresponding parameters play a critical role in characterizing the sensor response behavior. In this work, a two-site Langmuir kinetics model is applied to describe the adsorption/desorption response processes of a SnO2/reduced graphene oxide resistive gas sensor and the pertinent kinetic parameters are optimized based on the genetic algorithm (GA). For the robustness and fast convergence of the GA, the initial values and ranges of kinetic parameters are obtained step-by-step. This a priori knowledge is sufficient to guarantee reasonable parameter identification from experimental data. Moreover, the kinetics model and GA are integrated into graphical user interface software for subsequent application. Eventually, the exploration of improvements to experimental design is uncovered to increase the accuracy and reliability of the estimation.
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Affiliation(s)
- Xiaobo Chen
- First Clinical Medical College, Zhejiang Chinese Medical University, Hangzhou 310053, China
| | - Weifeng Jin
- College of Pharmaceutical Science, Zhejiang Chinese Medical University, Hangzhou 310053, China
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Du H, Xie G, Zhang Q. Enhanced Room Temperature NO 2 Sensing Performance of RGO Nanosheets by Building RGO/SnO 2 Nanocomposite System. SENSORS 2019; 19:s19214650. [PMID: 31717730 PMCID: PMC6864535 DOI: 10.3390/s19214650] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Revised: 10/17/2019] [Accepted: 10/24/2019] [Indexed: 11/16/2022]
Abstract
RGO/SnO2 nanocomposites were prepared by a simple blending method and then airbrushed on interdigitated electrodes to obtain the corresponding gas sensors. The characterizations of SEM, TEM, Raman, XRD and FTIR were used to characterize the microstructures, morphologies and surface chemical compositions of the nanocomposites, indicating that the two materials coexist in the composite films and the concentration of surface defects is affected by the amount of SnO2 nanoparticles. It is also found that the room temperature sensing performance of RGO to NO2 can be improved by introducing appropriate amount of SnO2 nanoparticles. The enhanced NO2 sensing properties are attributed to the rough surface structure and increased surface area and surface defects of the nanocomposite films. Since further reduction of RGO, heat treating the sensing films resulted in a decrease in the response and recovery times of the sensors. Furthermore, the sensor annealed at 200 ∘C exhibited a small baseline drift, wide detection range, good linearity, high stability and better selectivity.
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Affiliation(s)
- Hongfei Du
- School of Optoelectronic Science and Engineering, State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China (UESTC), Chengdu 610054, China; (H.D.); (G.X.)
- School of Mathematical Sciences, University of Electronic Sciences and Technology of China (UESTC), Chengdu 611731, China
| | - Guangzhong Xie
- School of Optoelectronic Science and Engineering, State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China (UESTC), Chengdu 610054, China; (H.D.); (G.X.)
| | - Qiuping Zhang
- Key Laboratory of Information Materials of Sichuan Province, School of Electrical and Information Engineering, Southwest University for Nationalities, Chengdu 610041, China
- Correspondence:
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Yan X, Wu Y, Li R, Shi C, Moro R, Ma Y, Ma L. High-Performance UV-Assisted NO 2 Sensor Based on Chemical Vapor Deposition Graphene at Room Temperature. ACS OMEGA 2019; 4:14179-14187. [PMID: 31508539 PMCID: PMC6732984 DOI: 10.1021/acsomega.9b00935] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Accepted: 08/09/2019] [Indexed: 05/30/2023]
Abstract
Nitrogen dioxide (NO2) is one of the most dangerous air pollutants that can affect human health even at the ppb (part per billion) level. Thus, the superior sensing performance of nitrogen dioxide gas sensors is an imperative for real-time environmental monitoring. Traditional solid-state sensors based on metal-oxide transistors have the drawbacks of high power consumption, high operating temperature, poor selectivity, and difficult integration with other electronics. In that respect, graphene-based gas sensors have been extensively studied as potential replacements. However, their advantages of high sensing efficiency, low power consumption, and simple electronic integration have been countered by their slow response and poor repeatability. Here, we report the fabrication of high-performance ultraviolet (UV)-assisted room temperature NO2 sensors based on chemical vapor deposition-grown graphene. UV irradiation improves the response of the sensor sevenfold with respect to the dark condition attaining 26% change in resistance at 100 ppm NO2 concentration with a practical detection limit below 1 ppm (42.18 ppb). In addition, the recovery time was shortened fivefold to a few minutes and the excellent repeatability. This work may provide a promising and practical method to mass produce room-temperature NO2 gas sensors for real-time environment monitoring due to its simple fabrication process, low cost, and practicality.
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Affiliation(s)
- Xin Yan
- Tianjin
International Center for Nanoparticles and Nanosystems and State Laboratory
of Precision Measuring Technology and Instruments, Tianjin University, Tianjin 300072, China
| | - Yanan Wu
- Tianjin
International Center for Nanoparticles and Nanosystems and State Laboratory
of Precision Measuring Technology and Instruments, Tianjin University, Tianjin 300072, China
| | - Rui Li
- Tianjin
International Center for Nanoparticles and Nanosystems and State Laboratory
of Precision Measuring Technology and Instruments, Tianjin University, Tianjin 300072, China
| | - Chengqian Shi
- Tianjin
International Center for Nanoparticles and Nanosystems and State Laboratory
of Precision Measuring Technology and Instruments, Tianjin University, Tianjin 300072, China
| | - Ramiro Moro
- Tianjin
International Center for Nanoparticles and Nanosystems and State Laboratory
of Precision Measuring Technology and Instruments, Tianjin University, Tianjin 300072, China
| | - Yanqing Ma
- Tianjin
International Center for Nanoparticles and Nanosystems and State Laboratory
of Precision Measuring Technology and Instruments, Tianjin University, Tianjin 300072, China
| | - Lei Ma
- Tianjin
International Center for Nanoparticles and Nanosystems and State Laboratory
of Precision Measuring Technology and Instruments, Tianjin University, Tianjin 300072, China
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Balasubramani V, Sureshkumar S, Rao TS, Sridhar TM. Impedance Spectroscopy-Based Reduced Graphene Oxide-Incorporated ZnO Composite Sensor for H 2S Investigations. ACS OMEGA 2019; 4:9976-9982. [PMID: 31460090 PMCID: PMC6648247 DOI: 10.1021/acsomega.9b00754] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Accepted: 05/10/2019] [Indexed: 06/10/2023]
Abstract
Electrochemical impedance spectroscopy (EIS) has been applied to measure the H2S gas response of the sensor fabricated on reduced graphene oxide (rGO)-incorporated nano-zinc oxide (n-ZnO) composites. These nanocomposites were prepared by a facile one-step solution route at room temperature. The structural, surface morphological, and elemental analyses of the composite material have been investigated. EIS was carried out to study the H2S gas-sensing properties of fabricated sensors. The developed sensor showed an optimal H2S gas response to various concentrations ranging from 2 to 100 ppm at 90 °C. The H2S gas-sensing performances of pure n-ZnO and various concentrations of rGO-incorporated n-ZnO were evaluated. The H2S gas-sensing results showed that n-ZnO/rGO composites exhibited high response when compared to pure n-ZnO. The enhanced H2S response was speculated to be ascribed due to two factors. First, rGO creates reactive sites for H2S molecule adsorption. Second, rGO has great electrical conductivity compared to n-ZnO that enables the active transport of electrons from H2S gas on interaction with the sensing layer, resulting in enhanced gas response at 90 °C temperatures.
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Affiliation(s)
- V. Balasubramani
- Department
of Analytical Chemistry, University of Madras, Guindy Campus, Chennai 600025, India
| | - S. Sureshkumar
- Department
of Chemistry, Rajalakshmi Engineering College, Chennai 602105, India
| | - T. Subba Rao
- Water
and Steam Chemistry Division, BARCF, Kalpakkam 603 102, India
| | - T. M. Sridhar
- Department
of Analytical Chemistry, University of Madras, Guindy Campus, Chennai 600025, India
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