All articles published by MDPI are made immediately available worldwide under an open access license. Adv. Appl. We are always looking for ways to improve customer experience on Elsevier.com. Highly sensitive formaldehyde gas sensors based on Y-doped SnO2 hierarchical flower-shaped nanostructures. Secondly, most of the SnO2 sensors currently used work at high temperature, which limits their wide application in detecting VOCs at room temperature. (2019). The dispersion of functional components is the key factor to realize good gas sensitivities (Wei et al., 2020). doi: 10.1016/j.snb.2017.12.050, Zhou, Q., Xu, L. N., Umar, A., Chen, W. G., and Kumar, R. (2018c). It is a highly sensitive formaldehyde detection material (Zhu et al., 2019). Enhanced sensing properties of SnO2 nanofibers with a novel structure by carbonization. More importantly, both methods are offline and cannot detect the content and change of VOCs in real-time. Sensor. Appl. doi: 10.1166/sam.2017.3111, Zhang, R., Ma, S. Y., Zhang, Q. X., Zhu, K. M., Tie, Y., Pei, S. T., et al. In order to change the nanostructure of a single material, there are other ways to improve the gas sensitivity of the sensor. 273, 418428. (2015). Analysis of aldehydes in beer using solid-phase microextraction with on-fiber derivatization and gas chromatography/mass spectrometry. Highly sensitive carbon monoxide (CO) gas sensors based on Ni and Zn doped SnO2 nanomaterials. Alloy. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). Cookie Settings, Terms and Conditions
3-D structures, such as microspheres, microflowers, and mesoporous structures, are assembled by diverse lower dimension fundamental blocks.
In addition, the Ag-doped Zn2SnO4/SnO2 hollow nanospheres responded to 50 ppm of formaldehyde with a value of 62.2 and a lower detection temperature of 140C (Zhang et al., 2019). (2017). Front. 
doi: 10.1016/j.pmatsci.2014.06.003, Ducere, J. M., Hemeryck, A., Esteve, A., Rouhani, M. D., Landa, G., Menini, P., et al. B Chem. 21 Articles, This article is part of the Research Topic, Creative Commons Attribution License (CC BY). Copyright 2022 Elsevier B.V. or its licensors or contributors. Appl. Institute of Applied Synthetic Chemistry, Vienna University of Technology, Getreidemarkt 9/163-AC, A-1060 Vienna, Austria. Chem. Long term exposure to acetone can stimulate human sensory organs and lead to inflammation. several techniques or approaches, or a comprehensive review paper with concise and precise updates on the latest Microwave-assisted and gram-scale synthesis of ultrathin SnO2 nanosheets with enhanced lithium storage properties. The uniform distribution of SnO2 NCs in the pore walls of TiO2 forms numerous n-n heterojunctions which are extremely useful for surface catalytic reaction. To request permission to reproduce material from this article, please go to the
A perspective on paper-based microfluidics: Current status and future trends. permission provided that the original article is clearly cited. B Chem. (2018). B Chem. doi: 10.1016/j.snb.2016.10.024, Shahabuddin, M., Umar, A., Tomar, M., and Gupta, V. (2017). In this review, the sensing mechanism of SnO2-based sensors detecting VOCs are discussed. Sensor. In the detection of common VOCs, the lower detection limit, response value and detection temperature of SnO2 based nanomaterials are different. Flexible cellulose-based devices for monitoring physical parametersDieric dos Santos de Abreu, Mathias Strauss and Murilo Santhiago12. permission is required to reuse all or part of the article published by MDPI, including figures and tables. Actuat. Cookie Notice
44, 43924399. Compared with low dimensional structure, 2-D structure possesses larger special surface area.
Actuat. Chem.
Reprinted with permission from Li et al. Front. Table 1. Surf. Visit our dedicated information section to learn more about MDPI. We use cookies to help provide and enhance our service and tailor content and ads. Sci. Int.
(2018). doi: 10.1016/j.matlet.2018.08.007, Zhu, Y. Q., Guo, H. Z., Zhai, H. Z., and Cao, C. B. Actuat. Depending on the main goal to be achieved in paper-based sensors, the fabrication methods and the analysis techniques can be tuned to fulfill the needs of the end-user. (D)SnO2/ZnO nanofibers. Comparison of SnO2 based nanomaterials for VOCs detection. Sensor. J. Front. (2019). J. provided correct acknowledgement is given. Analyst, 2019,144, 2467
Actuat. SnO2 based sensors has received extensive attention in the field of toxic gas detection due to their excellent performances with high sensitivity, fast response, long-term stability. 7, 27452753. However, it is anticipated that in the future, with advances in fabrication and analytical techniques, that there will be more new and innovative developments in paper-based sensors. There are also some organic waste gas shows a strong toxic effect, the human body in the excessive inhalation, will lead to coma or even death (Li G. et al., 2019). Paper-based sensors are a new alternative technology for fabricating simple, low-cost, portable and disposable analytical devices for many application areas including clinical diagnosis, food quality control and environmental monitoring. Multifarious aspects of electrochemical paper-based (bio)sensorsFabiana Arduini and Danila Moscone6. 9, 13501355. In addition, long-term stability is also one of the research hotspots of SnO2 sensors in the future. We use cookies on our website to ensure you get the best experience. One-step synthesis of micro-/mesoporous SnO2 spheres by solvothermal method for toluene gas sensor. Chem. cstc2016jcyjA0400), and the project of China Scholarship Council (CSC). to access the full features of the site or access our, Department of Industrial Chemistry, Addis Ababa Science and Technology University, P. O. Box.16417, Addis Ababa, Ethiopia, Institute of Applied Synthetic Chemistry, Vienna University of Technology, Getreidemarkt 9/163-AC, A-1060 Vienna, Austria. Sitemap. Sensor. Ag modified SnO2 nanoparticles prepared by hydrothermal in situ reduction improved the sensor's ability to detect formaldehyde. 
9: 11505-11526. doi: 10.1016/j.ceramint.2017.12.038, Zhou, Q., Umar, A., Sodki, E., Amine, A., Xu, L. N., Gui, Y. G., et al. doi: 10.1016/j.jallcom.2017.07.017, Zhang, K., Yang, X., Wang, Y., Bing, Y., Qiao, L., Liang, Z., et al. https://doi.org/10.3390/s120911505, Subscribe to receive issue release notifications and newsletters from MDPI journals, You can make submissions to other journals. Carbon materials and metal oxide semiconductor materials like SnO2, ZnO, WO3, and In2O3 have received scientific and technological importance and are widely used to detect VOCs gases (Luo et al., 2016; Lin et al., 2019; Zhao et al., 2019b). doi: 10.1016/j.snb.2018.05.039, Xu, X., Chen, Y., Zhang, G., Ma, S., Lu, Y., Bian, H., et al. Actuat. XDJK2019B021), the Chongqing Science and Technology Commission (CSTC) (No. Enhanced toluene sensing performances of Pd- loaded SnO2 cubic nanocages with porous nanoparticle-assembled shells. The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. 2013:127345. doi: 10.1155/2013/127345, Cheng, L., Ma, S. Y., Wang, T. T., and Luo, J. (2020). Sci. This section mainly reflects the changes in the gas-sensing properties of SnO2 nanomaterials from the aspects of structure and morphology design, ion doping, oxide composite and noble metal modification (Chen et al., 2013; Das and Jayaraman, 2014). 301:126845. doi: 10.1016/j.snb.2019.126845, Chen, W. G., Zhou, Q., Gao, T. Y., Su, X. P., and Wan, F. (2013). B Chem. This is an open access article distributed under the. Facile synthesis of Ca2+/Au co-doped SnO2 nanofibers and their application in acetone sensor. 256, 656664. He is also involved in teaching PhD courses in field of nanomaterial-based biosensors in several Spanish and international centres. If you are the author of this article, you do not need to request permission to reproduce figures
138, 1258612595. (2018b). 813:152170. doi: 10.1016/j.jallcom.2019.152170, Zhao, T., Qiu, P. P., Fan, Y. C., Yang, J. P., Jiang, W., Wang, L. J., et al. (2017). 243, 465474. Alloy. If you are an author contributing to an RSC publication, you do not need to request permission
Pt nanoparticles decorated SnO2 nanoneedles for effificient CO gas sensing applications. 6:364. doi: 10.3389/Fchem.2018.00364, Zhang, Q. Y., Zhou, Q., Yin, X. T., Liu, H. C., Xu, L. N., Tan, W. M., et al. Acs. B Chem. Appl. Highly sensitive acetone sensors based on flame-spray-made La2O3-doped SnO2 nanoparticulate thick films. published in the various research areas of the journal. 254, 178181. B., Tang, X. H., Huang, J. R., et al. When exposed to air, oxygen molecules would be adsorbed on the surface of the SnO2 nanostructures and capture electrons from the conduction band of SnO2 to generate chemisorbed oxygen species [O2-, O, and O2, depending on temperatures; (Shahabuddin et al., 2017; Zhou et al., 2019)]. doi: 10.1021/jacs.6b07355, Mahajan, S., and Jagtap, S. (2019). Metal oxide composite can not only achieve functional dispersion, but also form heterojunctions to promote the movement of charge carriers. Multilevel effective heterojunctions based on SnO2/ZnO 1D fibrous hierarchical structure with unique interface electronic effects. Despite great progress has been made in the application of SnO2 nanomaterials, there is still much room for further development. Sign in to view your account details and order history. Sens. B Chem. Bulk doping influence on the response of conductometric SnO2 gas sensors: understanding through cathodoluminescence study. Alloy. Different preparation methods will change the structure and morphology of SnO2 sensing materials and further enhance the gas sensitivity (Long et al., 2018; Zhang Y. J. et al., 2018; Zhou et al., 2018b). Publishing services by Elsevier B.V. on behalf of KeAi Communications Co. Ltd. https://doi.org/10.1016/j.sintl.2022.100189. Understanding wax printing: a simple micropatterning process for paper-based microfluidics. 143, 8487. Mater. (2015). The aim is to provide a snapshot of some of the most exciting work *
J. J. (2017). 42, 45974609. Moreover, the heterostructure formed by SnO2 and another metal oxide can promote the transfer of carriers between materials and change the conductivity and energy band structure of composite materials (Gusain et al., 2019; Wei et al., 2019). Nanopaper-based sensorsTina Naghdi, Hossein Yousefi, Amir Reza Sharifi and Hamed Golmohammadi10. Sensor. He is member of the Academics Working Group of BIST and coordinator of the Nanodiagnostics module of Nanotechnology Master of UAB. Plant-extract-mediated SnO2 nanoparticles: synthesis and applications. Sensing. This is due to the charge transfer between Ag and SnO2, which increases the absorption band on the composite by 20 nm, thus improving the gas sensitivity (Liu et al., 2019). In comparison to the 3-D structure, freestanding 2-D structures such as SnO2 nanosheets (Figure 1E) can provide better optimization including the modulation of the materials activity, surface polarization, and rich oxygen vacancies (Zhu et al., 2015). The synergistic effect between them improves the sensing performance of the composite nanomaterial to acetone gas (Zhu et al., 2018). This section summarizes the gas-sensitive characteristics of SnO2-based nanomaterials for the above gases, as shown in Table 1. paper; sensor; device; microfluidics; lab-on-a-chip; diagnostics; analytical, Help us to further improve by taking part in this short 5 minute survey, Using the Image Analysis Method for Describing Soil Detachment by a Single Water Drop Impact, CANoE: A Context-Aware Notification Model to Support the Care of Older Adults in a Nursing Home. Fetching data from CrossRef. Chem. Received: 29 January 2020; Accepted: 30 March 2020; Published: 05 May 2020. Actuat. Ion doping can change the cell parameters of the material, the number of suspensions on the surface of the material and the richness of defects, thereby enhance the gas sensitivity of the sensor (Korotcenkov and Cho, 2014). The cactus-like WO3-SnO2 nanocomposite was prepared by one-step hydrothermal method by attaching many tiny SnO2 nanospheres to large WO3 nanospheres, which provided many active sites for the acetone molecule and provided heterojunctions between WO3 and SnO2. Sensor. prior to publication. On the one hand, the p-n hybrid interface of p-type Ag2O and n-type SnO2 causes the energy band of the depletion layer to bend, increasing the initial resistance. This may take some time to load. doi: 10.1016/j.ijhydene.2016.12.054, Shao, S., Chen, X., Chen, Y., Lai, M., and Che, L. (2019). SnO2: a comprehensive review on structures and gas sensors. Prof. Merkoi has published 305 articles (H-index / citations: Google Scholar 77 / 20908; WOS 63 / 15617) and supervised 30 PhD theses. Department of Industrial Chemistry, Addis Ababa Science and Technology University, P. O. Box.16417, Addis Ababa, Ethiopia
262, 245262.
Due to these characteristics, paperbased potentiometric sensors are more ecofriendly, suitable to be used in resourcelimited areas, can be used in remote locations or onsite settings with lowcost analytical instrumentation. Only visits after 24 November 2015 are recorded.
Role of oxygen vacancies in nanostructured metal-oxide gas sensors: a review. Paper is also an ideal substrate to be used, considering that it is flexible, lightweight, mechanicallyresistant, a good medium for immobilization and trapping, and that it can be easily chemically and physically modified for customized applications, it can adsorb and transport liquid via capillary forces, can close the electrical circuit between electrodes when wet, it can be produced in diverse geometrical dimensions and porosities.
doi: 10.1016/j.pmatsci.2014.06.003, Ducere, J. M., Hemeryck, A., Esteve, A., Rouhani, M. D., Landa, G., Menini, P., et al. B Chem. 21 Articles, This article is part of the Research Topic, Creative Commons Attribution License (CC BY). Copyright 2022 Elsevier B.V. or its licensors or contributors. Appl. Institute of Applied Synthetic Chemistry, Vienna University of Technology, Getreidemarkt 9/163-AC, A-1060 Vienna, Austria. Chem. Long term exposure to acetone can stimulate human sensory organs and lead to inflammation. several techniques or approaches, or a comprehensive review paper with concise and precise updates on the latest Microwave-assisted and gram-scale synthesis of ultrathin SnO2 nanosheets with enhanced lithium storage properties. The uniform distribution of SnO2 NCs in the pore walls of TiO2 forms numerous n-n heterojunctions which are extremely useful for surface catalytic reaction. To request permission to reproduce material from this article, please go to the
A perspective on paper-based microfluidics: Current status and future trends. permission provided that the original article is clearly cited. B Chem. (2018). B Chem. doi: 10.1016/j.snb.2016.10.024, Shahabuddin, M., Umar, A., Tomar, M., and Gupta, V. (2017). In this review, the sensing mechanism of SnO2-based sensors detecting VOCs are discussed. Sensor. In the detection of common VOCs, the lower detection limit, response value and detection temperature of SnO2 based nanomaterials are different. Flexible cellulose-based devices for monitoring physical parametersDieric dos Santos de Abreu, Mathias Strauss and Murilo Santhiago12. permission is required to reuse all or part of the article published by MDPI, including figures and tables. Actuat. Cookie Notice
44, 43924399. Compared with low dimensional structure, 2-D structure possesses larger special surface area.
Actuat. Chem.
Reprinted with permission from Li et al. Front. Table 1. Surf. Visit our dedicated information section to learn more about MDPI. We use cookies to help provide and enhance our service and tailor content and ads. Sci. Int.
(2018). doi: 10.1016/j.matlet.2018.08.007, Zhu, Y. Q., Guo, H. Z., Zhai, H. Z., and Cao, C. B. Actuat. Depending on the main goal to be achieved in paper-based sensors, the fabrication methods and the analysis techniques can be tuned to fulfill the needs of the end-user. (D)SnO2/ZnO nanofibers. Comparison of SnO2 based nanomaterials for VOCs detection. Sensor. J. Front. (2019). J. provided correct acknowledgement is given. Analyst, 2019,144, 2467
Actuat. SnO2 based sensors has received extensive attention in the field of toxic gas detection due to their excellent performances with high sensitivity, fast response, long-term stability. 7, 27452753. However, it is anticipated that in the future, with advances in fabrication and analytical techniques, that there will be more new and innovative developments in paper-based sensors. There are also some organic waste gas shows a strong toxic effect, the human body in the excessive inhalation, will lead to coma or even death (Li G. et al., 2019). Paper-based sensors are a new alternative technology for fabricating simple, low-cost, portable and disposable analytical devices for many application areas including clinical diagnosis, food quality control and environmental monitoring. Multifarious aspects of electrochemical paper-based (bio)sensorsFabiana Arduini and Danila Moscone6. 9, 13501355. In addition, long-term stability is also one of the research hotspots of SnO2 sensors in the future. We use cookies on our website to ensure you get the best experience. One-step synthesis of micro-/mesoporous SnO2 spheres by solvothermal method for toluene gas sensor. Chem. cstc2016jcyjA0400), and the project of China Scholarship Council (CSC). to access the full features of the site or access our, Department of Industrial Chemistry, Addis Ababa Science and Technology University, P. O. Box.16417, Addis Ababa, Ethiopia, Institute of Applied Synthetic Chemistry, Vienna University of Technology, Getreidemarkt 9/163-AC, A-1060 Vienna, Austria. Sitemap. Sensor. Ag modified SnO2 nanoparticles prepared by hydrothermal in situ reduction improved the sensor's ability to detect formaldehyde. 9: 11505-11526. doi: 10.1016/j.ceramint.2017.12.038, Zhou, Q., Umar, A., Sodki, E., Amine, A., Xu, L. N., Gui, Y. G., et al. doi: 10.1016/j.jallcom.2017.07.017, Zhang, K., Yang, X., Wang, Y., Bing, Y., Qiao, L., Liang, Z., et al. https://doi.org/10.3390/s120911505, Subscribe to receive issue release notifications and newsletters from MDPI journals, You can make submissions to other journals. Carbon materials and metal oxide semiconductor materials like SnO2, ZnO, WO3, and In2O3 have received scientific and technological importance and are widely used to detect VOCs gases (Luo et al., 2016; Lin et al., 2019; Zhao et al., 2019b). doi: 10.1016/j.snb.2018.05.039, Xu, X., Chen, Y., Zhang, G., Ma, S., Lu, Y., Bian, H., et al. Actuat. XDJK2019B021), the Chongqing Science and Technology Commission (CSTC) (No. Enhanced toluene sensing performances of Pd- loaded SnO2 cubic nanocages with porous nanoparticle-assembled shells. The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. 2013:127345. doi: 10.1155/2013/127345, Cheng, L., Ma, S. Y., Wang, T. T., and Luo, J. (2020). Sci. This section mainly reflects the changes in the gas-sensing properties of SnO2 nanomaterials from the aspects of structure and morphology design, ion doping, oxide composite and noble metal modification (Chen et al., 2013; Das and Jayaraman, 2014). 301:126845. doi: 10.1016/j.snb.2019.126845, Chen, W. G., Zhou, Q., Gao, T. Y., Su, X. P., and Wan, F. (2013). B Chem. This is an open access article distributed under the. Facile synthesis of Ca2+/Au co-doped SnO2 nanofibers and their application in acetone sensor. 256, 656664. He is also involved in teaching PhD courses in field of nanomaterial-based biosensors in several Spanish and international centres. If you are the author of this article, you do not need to request permission to reproduce figures
138, 1258612595. (2018b). 813:152170. doi: 10.1016/j.jallcom.2019.152170, Zhao, T., Qiu, P. P., Fan, Y. C., Yang, J. P., Jiang, W., Wang, L. J., et al. (2017). 243, 465474. Alloy. If you are an author contributing to an RSC publication, you do not need to request permission
Pt nanoparticles decorated SnO2 nanoneedles for effificient CO gas sensing applications. 6:364. doi: 10.3389/Fchem.2018.00364, Zhang, Q. Y., Zhou, Q., Yin, X. T., Liu, H. C., Xu, L. N., Tan, W. M., et al. Acs. B Chem. Appl. Highly sensitive acetone sensors based on flame-spray-made La2O3-doped SnO2 nanoparticulate thick films. published in the various research areas of the journal. 254, 178181. B., Tang, X. H., Huang, J. R., et al. When exposed to air, oxygen molecules would be adsorbed on the surface of the SnO2 nanostructures and capture electrons from the conduction band of SnO2 to generate chemisorbed oxygen species [O2-, O, and O2, depending on temperatures; (Shahabuddin et al., 2017; Zhou et al., 2019)]. doi: 10.1021/jacs.6b07355, Mahajan, S., and Jagtap, S. (2019). Metal oxide composite can not only achieve functional dispersion, but also form heterojunctions to promote the movement of charge carriers. Multilevel effective heterojunctions based on SnO2/ZnO 1D fibrous hierarchical structure with unique interface electronic effects. Despite great progress has been made in the application of SnO2 nanomaterials, there is still much room for further development. Sign in to view your account details and order history. Sens. B Chem. Bulk doping influence on the response of conductometric SnO2 gas sensors: understanding through cathodoluminescence study. Alloy. Different preparation methods will change the structure and morphology of SnO2 sensing materials and further enhance the gas sensitivity (Long et al., 2018; Zhang Y. J. et al., 2018; Zhou et al., 2018b). Publishing services by Elsevier B.V. on behalf of KeAi Communications Co. Ltd. https://doi.org/10.1016/j.sintl.2022.100189. Understanding wax printing: a simple micropatterning process for paper-based microfluidics. 143, 8487. Mater. (2015). The aim is to provide a snapshot of some of the most exciting work *
J. J. (2017). 42, 45974609. Moreover, the heterostructure formed by SnO2 and another metal oxide can promote the transfer of carriers between materials and change the conductivity and energy band structure of composite materials (Gusain et al., 2019; Wei et al., 2019). Nanopaper-based sensorsTina Naghdi, Hossein Yousefi, Amir Reza Sharifi and Hamed Golmohammadi10. Sensor. He is member of the Academics Working Group of BIST and coordinator of the Nanodiagnostics module of Nanotechnology Master of UAB. Plant-extract-mediated SnO2 nanoparticles: synthesis and applications. Sensing. This is due to the charge transfer between Ag and SnO2, which increases the absorption band on the composite by 20 nm, thus improving the gas sensitivity (Liu et al., 2019). In comparison to the 3-D structure, freestanding 2-D structures such as SnO2 nanosheets (Figure 1E) can provide better optimization including the modulation of the materials activity, surface polarization, and rich oxygen vacancies (Zhu et al., 2015). The synergistic effect between them improves the sensing performance of the composite nanomaterial to acetone gas (Zhu et al., 2018). This section summarizes the gas-sensitive characteristics of SnO2-based nanomaterials for the above gases, as shown in Table 1. paper; sensor; device; microfluidics; lab-on-a-chip; diagnostics; analytical, Help us to further improve by taking part in this short 5 minute survey, Using the Image Analysis Method for Describing Soil Detachment by a Single Water Drop Impact, CANoE: A Context-Aware Notification Model to Support the Care of Older Adults in a Nursing Home. Fetching data from CrossRef. Chem. Received: 29 January 2020; Accepted: 30 March 2020; Published: 05 May 2020. Actuat. Ion doping can change the cell parameters of the material, the number of suspensions on the surface of the material and the richness of defects, thereby enhance the gas sensitivity of the sensor (Korotcenkov and Cho, 2014). The cactus-like WO3-SnO2 nanocomposite was prepared by one-step hydrothermal method by attaching many tiny SnO2 nanospheres to large WO3 nanospheres, which provided many active sites for the acetone molecule and provided heterojunctions between WO3 and SnO2. Sensor. prior to publication. On the one hand, the p-n hybrid interface of p-type Ag2O and n-type SnO2 causes the energy band of the depletion layer to bend, increasing the initial resistance. This may take some time to load. doi: 10.1016/j.ijhydene.2016.12.054, Shao, S., Chen, X., Chen, Y., Lai, M., and Che, L. (2019). SnO2: a comprehensive review on structures and gas sensors. Prof. Merkoi has published 305 articles (H-index / citations: Google Scholar 77 / 20908; WOS 63 / 15617) and supervised 30 PhD theses. Department of Industrial Chemistry, Addis Ababa Science and Technology University, P. O. Box.16417, Addis Ababa, Ethiopia
262, 245262.
Due to these characteristics, paperbased potentiometric sensors are more ecofriendly, suitable to be used in resourcelimited areas, can be used in remote locations or onsite settings with lowcost analytical instrumentation. Only visits after 24 November 2015 are recorded.
Role of oxygen vacancies in nanostructured metal-oxide gas sensors: a review. Paper is also an ideal substrate to be used, considering that it is flexible, lightweight, mechanicallyresistant, a good medium for immobilization and trapping, and that it can be easily chemically and physically modified for customized applications, it can adsorb and transport liquid via capillary forces, can close the electrical circuit between electrodes when wet, it can be produced in diverse geometrical dimensions and porosities.