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Zhang W, Chen X, Chen Y, Li HY, Liu H. Construction of semiconductor nanocomposites for room-temperature gas sensors. NANOSCALE 2024; 16:12883-12908. [PMID: 38919996 DOI: 10.1039/d4nr00441h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/27/2024]
Abstract
Gas sensors are essential for ensuring public safety and improving quality of life. Room-temperature gas sensors are notable for their potential economic benefits and low energy consumption, and their expected integration with wearable electronics, making them a focal point of contemporary research. Advances in nanomaterials and low-dimensional semiconductors have significantly contributed to the enhancement of room-temperature gas sensors. These advancements have focused on improving sensitivity, selectivity, and response/recovery times, with nanocomposites offering distinct advantages. The discussion here focuses on the use of semiconductor nanocomposites for gas sensing at room temperature, and provides a review of the latest synthesis techniques for these materials. This involves the precise adjustment of chemical compositions, microstructures, and morphologies. In addition, the design principles and potential functional mechanisms are examined. This is crucial for deepening the understanding and enhancing the operational capabilities of sensors. We also highlight the challenges faced in scaling up the production of nanocomposite materials. Looking ahead, semiconductor nanocomposites are expected to drive innovation in gas sensor technology due to their carefully crafted design and construction, paving the way for their extensive use in various sectors.
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Affiliation(s)
- Wenjian Zhang
- School of Integrated Circuits, Wuhan National Laboratory for Optoelectronics, Optics Valley Laboratory, Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan, Hubei 430074, P. R. China.
| | - Xinyi Chen
- School of Integrated Circuits, Wuhan National Laboratory for Optoelectronics, Optics Valley Laboratory, Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan, Hubei 430074, P. R. China.
| | - Yuexi Chen
- School of Integrated Circuits, Wuhan National Laboratory for Optoelectronics, Optics Valley Laboratory, Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan, Hubei 430074, P. R. China.
| | - Hua-Yao Li
- School of Integrated Circuits, Wuhan National Laboratory for Optoelectronics, Optics Valley Laboratory, Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan, Hubei 430074, P. R. China.
- Wenzhou Key Laboratory of Optoelectronic Materials and Devices Application, Wenzhou Advanced Manufacturing Institute of HUST, 1085 Meiquan Road, Wenzhou, Zhejiang 325035, P. R. China
| | - Huan Liu
- School of Integrated Circuits, Wuhan National Laboratory for Optoelectronics, Optics Valley Laboratory, Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan, Hubei 430074, P. R. China.
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Wu P, Li Y, Yang A, Tan X, Chu J, Zhang Y, Yan Y, Tang J, Yuan H, Zhang X, Xiao S. Advances in 2D Materials Based Gas Sensors for Industrial Machine Olfactory Applications. ACS Sens 2024; 9:2728-2776. [PMID: 38828988 DOI: 10.1021/acssensors.4c00431] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2024]
Abstract
The escalating development and improvement of gas sensing ability in industrial equipment, or "machine olfactory", propels the evolution of gas sensors toward enhanced sensitivity, selectivity, stability, power efficiency, cost-effectiveness, and longevity. Two-dimensional (2D) materials, distinguished by their atomic-thin profile, expansive specific surface area, remarkable mechanical strength, and surface tunability, hold significant potential for addressing the intricate challenges in gas sensing. However, a comprehensive review of 2D materials-based gas sensors for specific industrial applications is absent. This review delves into the recent advances in this field and highlights the potential applications in industrial machine olfaction. The main content encompasses industrial scenario characteristics, fundamental classification, enhancement methods, underlying mechanisms, and diverse gas sensing applications. Additionally, the challenges associated with transitioning 2D material gas sensors from laboratory development to industrialization and commercialization are addressed, and future-looking viewpoints on the evolution of next-generation intelligent gas sensory systems in the industrial sector are prospected.
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Affiliation(s)
- Peng Wu
- State Key Laboratory of Power Grid Environmental Protection, School of Electrical Engineering and Automation, Wuhan University, Wuhan, Hubei 430072, China
| | - Yi Li
- State Key Laboratory of Power Grid Environmental Protection, School of Electrical Engineering and Automation, Wuhan University, Wuhan, Hubei 430072, China
| | - Aijun Yang
- State Key Laboratory of Electrical Insulation and Power Equipment, Xi'an Jiaotong, No 28 XianNing West Road, Xi'an, Shanxi 710049, China
| | - Xiangyu Tan
- Electric Power Research Institute, Yunnan Power Grid Co., Ltd., Kunming, Yunnan 650217, China
| | - Jifeng Chu
- State Key Laboratory of Electrical Insulation and Power Equipment, Xi'an Jiaotong, No 28 XianNing West Road, Xi'an, Shanxi 710049, China
| | - Yifan Zhang
- State Key Laboratory of Power Grid Environmental Protection, School of Electrical Engineering and Automation, Wuhan University, Wuhan, Hubei 430072, China
| | - Yongxu Yan
- State Key Laboratory of Power Grid Environmental Protection, School of Electrical Engineering and Automation, Wuhan University, Wuhan, Hubei 430072, China
| | - Ju Tang
- State Key Laboratory of Power Grid Environmental Protection, School of Electrical Engineering and Automation, Wuhan University, Wuhan, Hubei 430072, China
| | - Hongye Yuan
- State Key Laboratory for Mechanical Behavior of Materials, Shaanxi International Research Center for Soft Matter, School of Materials Science and Engineering, Xi'an Jiaotong University, Xi'an, Shanxi 710049, China
| | - Xiaoxing Zhang
- Hubei Engineering Research Center for Safety Monitoring of New Energy and Power Grid Equipment, Hubei University of Technology, Wuhan, Hubei 430068, China
| | - Song Xiao
- State Key Laboratory of Power Grid Environmental Protection, School of Electrical Engineering and Automation, Wuhan University, Wuhan, Hubei 430072, China
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Lv J, Zhang C, Qu G, Pan K, Qin J, Wei K, Liang Y. Modification strategies for semiconductor metal oxide nanomaterials applied to chemiresistive NO x gas sensors: A review. Talanta 2024; 273:125853. [PMID: 38460422 DOI: 10.1016/j.talanta.2024.125853] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2023] [Revised: 02/14/2024] [Accepted: 02/28/2024] [Indexed: 03/11/2024]
Abstract
Semiconductor metal oxides (SMOs) nanomaterials are a category of sensing materials that are widely applied to chemiresistive NOx gas sensors. However, there is much space to improve the sensing performance of SMOs nanomaterials. Therefore, how to improve the sensing performance of SMOs nanomaterials for NOx gases has always attracted the interest of researchers. Up to now, there are few reviews focus on the modification strategies of SMOs which applied to NOx gas sensors. In order to compensate for the limitation, this review summarizes the existing modification strategies of SMOs, hoping to provide researchers a view of the research progress in this filed as comprehensive as possible. This review focuses on the progress of the modification of SMOs nanomaterials for chemiresistive NOx (NO, NO2) gas sensors, including the morphology modulation of SMOs, compositing SMOs, loading noble metals, doping metal ions, compositing with carbon nanomaterials, compositing with biomass template, and compositing with MXene, MOFs, conducting polymers. The mechanism of each strategy to enhance the NOx sensing performance of SMOs-based nanomaterials is also discussed and summarized. In addition, the limitations of some of the modification strategies and ways to address them are discussed. Finally, future perspectives for SMOs-based NOx gas sensors are also discussed.
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Affiliation(s)
- Jiaxin Lv
- Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Yunnan, 650500, China; National Regional Engineering Research Center-NCW, Yunnan, 650500, China
| | - Chaoneng Zhang
- Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Yunnan, 650500, China; National Regional Engineering Research Center-NCW, Yunnan, 650500, China
| | - Guangfei Qu
- Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Yunnan, 650500, China; National Regional Engineering Research Center-NCW, Yunnan, 650500, China.
| | - Keheng Pan
- Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Yunnan, 650500, China; National Regional Engineering Research Center-NCW, Yunnan, 650500, China
| | - Jin Qin
- Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Yunnan, 650500, China; National Regional Engineering Research Center-NCW, Yunnan, 650500, China
| | - Kunling Wei
- Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Yunnan, 650500, China; National Regional Engineering Research Center-NCW, Yunnan, 650500, China
| | - Yuqi Liang
- Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Yunnan, 650500, China; National Regional Engineering Research Center-NCW, Yunnan, 650500, China
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Chen H, Chen H, Chen J, Song M. Gas Sensors Based on Semiconductor Metal Oxides Fabricated by Electrospinning: A Review. SENSORS (BASEL, SWITZERLAND) 2024; 24:2962. [PMID: 38793817 PMCID: PMC11125222 DOI: 10.3390/s24102962] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2024] [Revised: 04/29/2024] [Accepted: 05/03/2024] [Indexed: 05/26/2024]
Abstract
Electrospinning has revolutionized the field of semiconductor metal oxide (SMO) gas sensors, which are pivotal for gas detection. SMOs are known for their high sensitivity, rapid responsiveness, and exceptional selectivity towards various types of gases. When synthesized via electrospinning, they gain unmatched advantages. These include high porosity, large specific surface areas, adjustable morphologies and compositions, and diverse structural designs, improving gas-sensing performance. This review explores the application of variously structured and composed SMOs prepared by electrospinning in gas sensors. It highlights strategies to augment gas-sensing performance, such as noble metal modification and doping with transition metals, rare earth elements, and metal cations, all contributing to heightened sensitivity and selectivity. We also look at the fabrication of composite SMOs with polymers or carbon nanofibers, which addresses the challenge of high operating temperatures. Furthermore, this review discusses the advantages of hierarchical and core-shell structures. The use of spinel and perovskite structures is also explored for their unique chemical compositions and crystal structure. These structures are useful for high sensitivity and selectivity towards specific gases. These methodologies emphasize the critical role of innovative material integration and structural design in achieving high-performance gas sensors, pointing toward future research directions in this rapidly evolving field.
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Affiliation(s)
- Hao Chen
- School of Applied Science and Technology, Hainan University, Danzhou 571799, China; (H.C.); (H.C.); (J.C.)
| | - Huayang Chen
- School of Applied Science and Technology, Hainan University, Danzhou 571799, China; (H.C.); (H.C.); (J.C.)
| | - Jiabao Chen
- School of Applied Science and Technology, Hainan University, Danzhou 571799, China; (H.C.); (H.C.); (J.C.)
| | - Mingxin Song
- School of Electronic Science and Technology, Hainan University, Haikou 570228, China
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Lin PK, Qin Y, Qi X, Huang L. Improved isoprene detection performance of Si-doped WO 3 films deposited by sputtering and post-annealing. RSC Adv 2024; 14:13618-13627. [PMID: 38665489 PMCID: PMC11043919 DOI: 10.1039/d4ra00184b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2024] [Accepted: 04/12/2024] [Indexed: 04/28/2024] Open
Abstract
Si-doped WO3 films were sputtered at room temperature and then annealed in air at 500 °C. The Si doping resulted in structural distortion from space group P21/n to Pc. A high density of pores with a diameter of ∼20 nm was observed in the films, which is ideal for gas sensing applications because of the easy diffusion of gas. Isoprene sensitivity, which is defined as the resistance ratio measured in pure air and in air containing 5 ppm isoprene, was greatly improved by the Si doping. The films containing 6.3 at% Si showed the highest sensitivity of 7.7 at a working temperature of 325 °C. However, despite a lower sensitivity of 6.9 measured at 350 °C, the films exhibited better gas selectivity for isoprene over a range of reference gases, including methanol, ethanol, acetone, CO and CO2. The response and recovery times of the films were very short, being less than 1.5 and 3.0 seconds, respectively. Detailed characterization with a range of techniques verified that the increase in gas sensitivity in the Si-doped films was related to better oxygen adsorbability as a consequence of an increase in positively-charged oxygen vacancies introduced by the aliovalent substitution of W6+ by Si4+.
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Affiliation(s)
- Pin-Kuan Lin
- Department of Materials Science and Engineering, National Cheng Kung University Tainan City 70101 Taiwan
| | - Yi Qin
- Department of Materials Science and Engineering, National Cheng Kung University Tainan City 70101 Taiwan
| | - Xiaoding Qi
- Department of Materials Science and Engineering, National Cheng Kung University Tainan City 70101 Taiwan
- Centre for Micro/Nano Science and Technology, National Cheng Kung University Tainan City 70101 Taiwan
| | - Liji Huang
- Siargo Ltd. Santa Clara California 95054 USA
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Pawar KK, Kumar A, Mirzaei A, Kumar M, Kim HW, Kim SS. 2D nanomaterials for realization of flexible and wearable gas sensors: A review. CHEMOSPHERE 2024; 352:141234. [PMID: 38278446 DOI: 10.1016/j.chemosphere.2024.141234] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Revised: 01/03/2024] [Accepted: 01/14/2024] [Indexed: 01/28/2024]
Abstract
Gas sensors are extensively employed for monitoring and detection of hazardous gases and vapors. Many of them are produced on rigid substrates, but flexible and wearable gas sensors are needed for intriguing usage including the internet of things (IoT) and medical devices. The materials with the greatest potential for the fabrication of flexible and wearable gas sensing devices are two-dimensional (2D) semiconducting nanomaterials, which consist of graphene and its substitutes, transition metal dichalcogenides, and MXenes. These types of materials have good mechanical flexibility, high charge carrier mobility, a large area of surface, an abundance of defects and dangling bonds, and, in certain instances adequate transparency and ease of synthesis. In this review, we have addressed the different 2D nonmaterial properties for gas sensing in the context of fabrication of flexible/wearable gas sensors. We have discussed the sensing performance of flexible/wearable gas sensors in various forms such as pristine, composite and noble metal decorated. We believe that content of this review paper is greatly useful for the researchers working in the research area of fabrication of flexible/wearable gas sensors.
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Affiliation(s)
- Krishna Kiran Pawar
- Division of Materials Science and Engineering, Hanyang University, Seoul, 04763, South Korea; The Research Institute of Industrial Science, Hanyang University, Seoul, 04763, South Korea; School of Nanoscience and Technology, Shivaji University, Kolhapur, 416004, India
| | - Ashok Kumar
- Department of Electrical Engineering, Indian Institute of Technology, Jodhpur, 342030, India
| | - Ali Mirzaei
- Department of Materials Science and Engineering, Shiraz University of Technology, Shiraz, 715557-13876, Iran
| | - Mahesh Kumar
- Department of Electrical Engineering, Indian Institute of Technology, Jodhpur, 342030, India; Department of Cybernetics, Nanotechnology and Data Processing, Faculty of Automatic Control, Electronics and Computer Science, Silesian University of Technology, Akademicka 16, 44-100, Gliwice, Poland
| | - Hyoun Woo Kim
- Division of Materials Science and Engineering, Hanyang University, Seoul, 04763, South Korea.
| | - Sang Sub Kim
- Department of Materials Science and Engineering, Inha University, Incheon, 22212, South Korea.
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Fu L, You S, Li G, Li X, Fan Z. Application of Semiconductor Metal Oxide in Chemiresistive Methane Gas Sensor: Recent Developments and Future Perspectives. Molecules 2023; 28:6710. [PMID: 37764486 PMCID: PMC10536930 DOI: 10.3390/molecules28186710] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Revised: 09/13/2023] [Accepted: 09/17/2023] [Indexed: 09/29/2023] Open
Abstract
The application of semiconductor metal oxides in chemiresistive methane gas sensors has seen significant progress in recent years, driven by their promising sensitivity, miniaturization potential, and cost-effectiveness. This paper presents a comprehensive review of recent developments and future perspectives in this field. The main findings highlight the advancements in material science, sensor fabrication techniques, and integration methods that have led to enhanced methane-sensing capabilities. Notably, the incorporation of noble metal dopants, nanostructuring, and hybrid materials has significantly improved sensitivity and selectivity. Furthermore, innovative sensor fabrication techniques, such as thin-film deposition and screen printing, have enabled cost-effective and scalable production. The challenges and limitations facing metal oxide-based methane sensors were identified, including issues with sensitivity, selectivity, operating temperature, long-term stability, and response times. To address these challenges, advanced material science techniques were explored, leading to novel metal oxide materials with unique properties. Design improvements, such as integrated heating elements for precise temperature control, were investigated to enhance sensor stability. Additionally, data processing algorithms and machine learning methods were employed to improve selectivity and mitigate baseline drift. The recent developments in semiconductor metal oxide-based chemiresistive methane gas sensors show promising potential for practical applications. The improvements in sensitivity, selectivity, and stability achieved through material innovations and design modifications pave the way for real-world deployment. The integration of machine learning and data processing techniques further enhances the reliability and accuracy of methane detection. However, challenges remain, and future research should focus on overcoming the limitations to fully unlock the capabilities of these sensors. Green manufacturing practices should also be explored to align with increasing environmental consciousness. Overall, the advances in this field open up new opportunities for efficient methane monitoring, leak prevention, and environmental protection.
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Affiliation(s)
- Li Fu
- Key Laboratory of Novel Materials for Sensor of Zhejiang Province, College of Materials and Environmental Engineering, Hangzhou Dianzi University, Hangzhou 310018, China;
- Research and Development Center, Siterwell Electronics Co., Ltd., Ningbo 315000, China; (G.L.); (Z.F.)
| | - Shixi You
- Research and Development Center, Siterwell Electronics Co., Ltd., Ningbo 315000, China; (G.L.); (Z.F.)
| | - Guangjun Li
- Research and Development Center, Siterwell Electronics Co., Ltd., Ningbo 315000, China; (G.L.); (Z.F.)
| | - Xingxing Li
- Key Laboratory of Novel Materials for Sensor of Zhejiang Province, College of Materials and Environmental Engineering, Hangzhou Dianzi University, Hangzhou 310018, China;
| | - Zengchang Fan
- Research and Development Center, Siterwell Electronics Co., Ltd., Ningbo 315000, China; (G.L.); (Z.F.)
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Wang T, Chu Y, Li X, Liu Y, Luo H, Zhou D, Deng F, Song X, Lu G, Yu J. Zeolites as a Class of Semiconductors for High-Performance Electrically Transduced Sensing. J Am Chem Soc 2023; 145:5342-5352. [PMID: 36812430 DOI: 10.1021/jacs.2c13160] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/24/2023]
Abstract
Zeolites are widely used as catalysts and adsorbents in the chemical industry, but their potential for electronic devices has been stunted to date, as they are commonly recognized as electronic insulators. Here, we have for the first time demonstrated that Na-type ZSM-5 zeolites are ultrawide-direct-band-gap semiconductors based on optical spectroscopy, variable-temperature current-voltage characteristics, and photoelectric effect as well as electronic structure theoretical calculations and further unraveled the band-like charge transport mechanism in electrically conductive zeolites. The increase in charge-compensating Na+ cations in Na-ZSM-5 decreases the band gap and affects its density of states, shifting the Fermi level close to the conduction band. Remarkably, the semiconducting Na-ZSM-5 zeolites have been first applied for constructing electrically transduced sensors that can sense trace-level (77 ppb) ammonia with unprecedentedly high sensitivity, negligible cross-sensitivity, and high stability under moisture ambient conditions compared with conventional semiconducting materials and conductive metal-organic frameworks (MOFs). The charge density difference shows that the massive electron transfer between NH3 molecules and Na+ cations ascribed to Lewis acid sites enables electrically transduced chemical sensing. This work opens a new era of zeolites in applications of sensing, optics, and electronics.
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Affiliation(s)
- Tianshuang Wang
- State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, Jilin University, Changchun 130012, China.,International Center of Future Science, Jilin University, Changchun 130012, China
| | - Yueying Chu
- National Center for Magnetic Resonance in Wuhan, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan 430071, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xiao Li
- State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, Jilin University, Changchun 130012, China
| | - Yinghao Liu
- State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, Jilin University, Changchun 130012, China
| | - Hao Luo
- State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, Jilin University, Changchun 130012, China
| | - Donglei Zhou
- State Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, Changchun 130012, China
| | - Feng Deng
- National Center for Magnetic Resonance in Wuhan, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan 430071, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xiaowei Song
- State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, Jilin University, Changchun 130012, China
| | - Geyu Lu
- State Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, Changchun 130012, China
| | - Jihong Yu
- State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, Jilin University, Changchun 130012, China.,International Center of Future Science, Jilin University, Changchun 130012, China
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Electrospun ZnO/Pd Nanofibers as Extremely Sensitive Material for Hydrogen Detection in Oxygen Free Gas Phase. Polymers (Basel) 2022; 14:polym14173481. [PMID: 36080555 PMCID: PMC9459723 DOI: 10.3390/polym14173481] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2022] [Revised: 08/21/2022] [Accepted: 08/23/2022] [Indexed: 11/17/2022] Open
Abstract
The development of safety sensors is an urgent necessity for the successful use of hydrogen in real conditions, which may differ, in particular, by the oxygen content in the surrounding atmosphere. Palladium-modified zinc oxide shows the high sensitivity when detecting hydrogen in air; however, studies of the sensor properties and the operation mechanism of the ZnO/Pd sensor when reducing gases are detected in an oxygen deficient or inert atmosphere have not been effectuated. In this work, we synthesized the ZnO and ZnO/Pd nanofibers by electrospinning and for the first time determined their sensor properties in the detection of CO, NH3 and H2 in different oxygen backgrounds. The microstructure and composition of nanofibers were characterized by electron microscopy, X-ray diffraction, X-ray fluorescent spectroscopy, and X-ray photoelectron spectroscopy. The interaction with the gas phase was investigated in situ by diffuse reflectance IR Fourier transform spectroscopy (DRIFTS). The sensor properties of ZnO and ZnO/Pd nanofibers were studied at 100–450 °C towards CO, NH3 and H2 in the N2/O2 gas mixtures containing 0.0005–20% O2. When detecting CO, a decrease in the oxygen concentration from 20 to 0.0005% in the gas phase does not lead to a significant change in the sensor response. At the same time, when detecting NH3 and especially H2, a decrease in oxygen concentration down to 0.0005% results in the dramatic increase in the sensor response of ZnO/Pd nanofibers. This result is discussed in terms of palladium hydride formation, modulation of the potential barrier at the ZnO/Pd interface, as well as changes in the concentration of donor defects and charge carriers in the ZnO matrix. Synthesized electrospun ZnO/Pd nanofibers are extremely promising materials for sensors for detecting hydrogen in an oxygen free atmosphere.
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