Influence of Deposition Potential on Structure of ZnO Nanowires Synthesized in Track-Etched Membranes

Single-crystal ZnO nanowires long up to several microns were fabricated by one-step electrochemical deposition. A template-based process employing track-etched polycarbonate (TE-PC) membranes was used for this purpose. The morphology and the structure characteristics of the ZnO nanowires were analyzed by means of Scanning Electron Microscopy (SEM), Focused Ion Beam (FIB), Transmission Electron Microscopy (TEM), and Selected Area Electron Diffraction (SAED). The growth process conditions turned out to have a marked influence on the crystal nature and morphology of the nanowires. Deposition rates ranging from 0.4 nm s -1 and up to 0.6 nm s -1 were recorded for the growth of ZnO nanowires. The obtained results showed that by using carefully controlled deposition conditions single crystalline nanowires and fine-grained structures can be routinely obtained. © 2012 The Electrochemical Society.This work was supported by the European Commission through the program PEOPLE, by the project no. MRTN-CT-2006-035884.Pruna, AI.; Pullini, D.; Busquets Mataix, DJ. (2012). Influence of Deposition Potential on Structure of ZnO Nanowires Synthesized in Track-Etched Membranes. Journal of The Electrochemical Society. 159(4):92-98. doi:10.1149/2.003205jesS9298159

High-Efficiency Electrodeposition of Large Scale ZnO Nanorod Arrays for Thin Transparent Electrodes

In the present work an effective technique to synthesize large-scale c-axis oriented ZnO nanorod (NR) arrays is presented. The manuscript reports a single-step cathodic electrodeposition, either in aqueous and organic electrolytes, to fill up ultra-thin anodic nanoporous alumina templates. Prior to growing, self-ordered hexagonal array of cylindrical nanopores have been fabricated by anodizing Al thin films previously deposited onto ITOglass substrates. The diameter and the aspect ratio of the vertically aligned nanopores are about 60 nm and 8:1, respectively. The results of this work demonstrate that using dimethyl sulfoxide (DMSO) as an electrolyte leads to a growth more homogeneous in shape and crystallinity, and with 60 deposition efficiency - the highest by now in literature. This fact is most probably due to a better infiltration of the alumina nanopores by this electrolyte. SEM and XRD analysis were employed for the study of morphology and crystalline structure of the obtained ZnO NR. These measurements showed furthermore that ZnO nanorod arrays are uniformly embedded into the hexagonally ordered nanopores of the anodic alumina membrane. DMSO proved to be an optimal electrolyte to obtain single-crystalline ZnO NR arrays, highly transparent in visible light range (80 transmittance). © 2011 The Electrochemical Society.The authors thank for the financial support by the European Commission, DG Research through the program PEOPLE, by the project no. MRTN-CT-2006-035884.Pullini, D.; Pruna, AI.; Zanin, S.; Busquets Mataix, DJ. (2012). High-Efficiency Electrodeposition of Large Scale ZnO Nanorod Arrays for Thin Transparent Electrodes. Journal of The Electrochemical Society. 159(2):45-51. doi:10.1149/2.093202jesS4551159

Hydrothermal-Freeze-Casting of Poly(amidoamine)-Modified Graphene Aerogels towards CO2 Adsorption

[EN] This article presents novel poly(amidoamine) (PAMAM) dendrimer-modified with partially-reduced graphene oxide (rGO) aerogels, obtained using the combined solvothermal synthesis-freeze-casting approach. The properties of modified aerogels are investigated with varying synthesis conditions, such as dendrimer generation (G), GO:PAMAM wt. ratio, solvothermal temperature, and freeze-casting rate. Scanning electron microscopy, Fourier Transform Infrared spectroscopy, Raman spectroscopy, X-ray photoelectron spectroscopy are employed to characterize the aerogels. The results indicate a strong correlation of the synthesis conditions with N content, N/C ratio, and nitrogen contributions in the modified aerogels. Our results show that the best CO2 adsorption performance was exhibited by the aerogels modified with higher generation (G7) dendrimer at low GO:PAMAM ratio as 2:0.1 mg mL(-1) and obtained at higher solvothermal temperature and freeze-casting in liquid nitrogen. The enclosed results are indicative of a viable approach to modify graphene aerogels towards improving the CO2 capture.This research was supported by European Commission through the GRAMOFON project, contract No. H2020-LCE-24-2016-727619.Pruna, AI.; Cárcel, AC.; Benedito, A.; Giménez Torres, E. (2021). Hydrothermal-Freeze-Casting of Poly(amidoamine)-Modified Graphene Aerogels towards CO2 Adsorption. International Journal of Molecular Sciences. 22(17):1-15. https://doi.org/10.3390/ijms22179333115221

Tailoring the Performance of Graphene Aerogels for Oil/Organic Solvent Separation by 1-Step Solvothermal Approach

[EN] Ultra-light eco-friendly graphene oxide (GO)-based aerogels are reported by simple one-step solvothermal self-assembly. The effect of varying parameters such as C/O ratio of GO; reducing agent amount; temperature; and duration on the properties of the aerogels was studied. The structural and vibrational features and hydrophobic surface properties of the obtained aerogels were obtained by XRD; FTIR; XPS; Raman; SEM; and contact angle measurements. The effect of synthesis conditions on the engine oil and organic solvent absorption properties was assessed. The results indicated that the lower the C/O ratio of GO, the better the absorption properties, with the best performance for oil uptake reaching 86 g g(-1). The obtained results indicate the approach based on ice-templating and the tailoring of oxygen content in GO make the resulting aerogels potential candidates for use in oil spill and organic solvent treatments.This research was supported by European Commission through GRAMOFON project, contract No. H2020-LCE-24-2016-727619.Pruna, AI.; Cárcel, AC.; Barjola, A.; Benedito, A.; Giménez Torres, E. (2019). Tailoring the Performance of Graphene Aerogels for Oil/Organic Solvent Separation by 1-Step Solvothermal Approach. Nanomaterials. 9(8):1-11. https://doi.org/10.3390/nano90810771119

Factorial electrochemical design for tailoring of morphological and optical properties of Cu2O

[EN] The electrodeposition of cuprous oxide (Cu2O) onto FTO-coated glass substrate was studied by using a statistical approach in order to control the Cu2O morphology and optical properties. The factorial design considered four electrodeposition conditions at two representative levels as input variables (electrolyte temperature and pH, deposition potential and duration) and the deposition charge and morphology of obtained Cu2O as the output variables. The morphology analysis showed the highest influence on crystal shape was exhibited by electrolyte temperature and pH, reaching significance levels of 95 and 98%, respectively. Temperature as low as 35°C and pH 12.2 results in cubic morphology, while other parameters result in octahedron shape. The highest absorbance was exhibited by the Cu2O with cubic morphology.AP acknowledges financial support from Romanian National Authority for Scientific Research and Innovation, CNCS - UEFISCDI (project number PN-II-RU-TE-2014-4-0806].Cembrero-Coca, P.; Cembrero Cil, J.; Busquets Mataix, DJ.; Pérez Puig, MA.; Marí, B.; Pruna, AI. (2017). Factorial electrochemical design for tailoring of morphological and optical properties of Cu2O. Materials Science and Technology. 33(17):2102-2109. https://doi.org/10.1080/02670836.2017.1349595S210221093317Rakhshani, A. E. (1987). Measurement of dispersion in electrodeposited Cu2O. Journal of Applied Physics, 62(4), 1528-1529. doi:10.1063/1.339619Chen, L.-C. (2013). Review of preparation and optoelectronic characteristics of Cu2O-based solar cells with nanostructure. Materials Science in Semiconductor Processing, 16(5), 1172-1185. doi:10.1016/j.mssp.2012.12.028Hsu, Y.-K., Lin, H.-H., Wu, J.-R., Chen, M.-H., Chen, Y.-C., & Lin, Y.-G. (2014). Electrochemical growth and characterization of a p-Cu2O thin film on n-ZnO nanorods for solar cell application. RSC Advances, 4(15), 7655. doi:10.1039/c3ra47188hChou, S.-M., Hon, M.-H., Leu, I.-C., & Lee, Y.-H. (2008). Al-Doped ZnO∕Cu[sub 2]O Heterojunction Fabricated on (200) and (111)-Orientated Cu[sub 2]O Substrates. Journal of The Electrochemical Society, 155(11), H923. doi:10.1149/1.2980424Siegfried, M. J., & Choi, K.-S. (2004). Electrochemical Crystallization of Cuprous Oxide with Systematic Shape Evolution. Advanced Materials, 16(19), 1743-1746. doi:10.1002/adma.200400177Siegfried, M. J., & Choi, K.-S. (2005). Directing the Architecture of Cuprous Oxide Crystals during Electrochemical Growth. Angewandte Chemie International Edition, 44(21), 3218-3223. doi:10.1002/anie.200463018Yang, W.-Y., Kim, W.-G., & Rhee, S.-W. (2008). Radio frequency sputter deposition of single phase cuprous oxide using Cu2O as a target material and its resistive switching properties. Thin Solid Films, 517(2), 967-971. doi:10.1016/j.tsf.2008.08.184Reddy, A. S., Uthanna, S., & Reddy, P. S. (2007). Properties of dc magnetron sputtered Cu2O films prepared at different sputtering pressures. Applied Surface Science, 253(12), 5287-5292. doi:10.1016/j.apsusc.2006.11.051Laik, B., Poizot, P., & Tarascon, J.-M. (2002). The Electrochemical Quartz Crystal Microbalance as a Means for Studying the Reactivity of Cu[sub 2]O toward Lithium. Journal of The Electrochemical Society, 149(3), A251. doi:10.1149/1.1445430Fu, L. J., Gao, J., Zhang, T., Cao, Q., Yang, L. C., Wu, Y. P., … Wu, H. Q. (2007). Preparation of Cu2O particles with different morphologies and their application in lithium ion batteries. Journal of Power Sources, 174(2), 1197-1200. doi:10.1016/j.jpowsour.2007.06.030Zhou, Y., & Switzer, J. A. (1998). Electrochemical Deposition and Microstructure of Copper (I) Oxide Films. Scripta Materialia, 38(11), 1731-1738. doi:10.1016/s1359-6462(98)00091-8Budevski, E., Staikov, G., & Lorenz, W. J. (2000). Electrocrystallization. Electrochimica Acta, 45(15-16), 2559-2574. doi:10.1016/s0013-4686(00)00353-4Morales, J., Sánchez, L., Bijani, S., Martı́nez, L., Gabás, M., & Ramos-Barrado, J. R. (2005). Electrodeposition of Cu[sub 2]O: An Excellent Method for Obtaining Films of Controlled Morphology and Good Performance in Li-Ion Batteries. Electrochemical and Solid-State Letters, 8(3), A159. doi:10.1149/1.1854126Holzschuh, H., & Suhr, H. (1990). Deposition of copper oxide (Cu2O, CuO) thin films at high temperatures by plasma-enhanced CVD. Applied Physics A Solids and Surfaces, 51(6), 486-490. doi:10.1007/bf00324731Jeong, S., & Aydil, E. S. (2009). Heteroepitaxial growth of Cu2O thin film on ZnO by metal organic chemical vapor deposition. Journal of Crystal Growth, 311(17), 4188-4192. doi:10.1016/j.jcrysgro.2009.07.020Pruna, A., Pullini, D., & Busquets, D. (2015). Effect of AZO film as seeding substrate on the electrodeposition and properties of Al-doped ZnO nanorod arrays. Ceramics International, 41(10), 14492-14500. doi:10.1016/j.ceramint.2015.07.087Pruna, A., Pullini, D., Tamvakos, D., Tamvakos, A., & Busquets-Mataix, D. (2015). Effect of tin-doped indium oxide film on electrodeposition of ZnO nanostructures. Materials Science and Technology, 31(14), 1794-1799. doi:10.1179/1743284715y.0000000016Pruna, A., Reyes-Tolosa, M. D., Pullini, D., Hernandez-Fenollosa, M. A., & Busquets-Mataix, D. (2015). Seed-free electrodeposition of ZnO bi-pods on electrophoretically-reduced graphene oxide for optoelectronic applications. Ceramics International, 41(2), 2381-2388. doi:10.1016/j.ceramint.2014.10.052Cembrero, J., Pruna, A., Pullini, D., & Busquets-Mataix, D. (2014). Effect of combined chemical and electrochemical reduction of graphene oxide on morphology and structure of electrodeposited ZnO. Ceramics International, 40(7), 10351-10357. doi:10.1016/j.ceramint.2014.03.008Prună, A., Pullini, D., & Mataix, D. B. (2012). Influence of Deposition Potential on Structure of ZnO Nanowires Synthesized in Track-Etched Membranes. Journal of The Electrochemical Society, 159(4), E92-E98. doi:10.1149/2.003205jesJiang, X., Zhang, M., Shi, S., He, G., Song, X., & Sun, Z. (2014). Microstructure and optical properties of nanocrystalline Cu2O thin films prepared by electrodeposition. Nanoscale Research Letters, 9(1), 219. doi:10.1186/1556-276x-9-219Yu, X., Li, X., Zheng, G., Wei, Y., Zhang, A., & Yao, B. (2013). Preparation and properties of KCl-doped Cu2O thin film by electrodeposition. Applied Surface Science, 270, 340-345. doi:10.1016/j.apsusc.2013.01.026Bijani, S., Schrebler, R., Dalchiele, E. A., Gabás, M., Martínez, L., & Ramos-Barrado, J. R. (2011). Study of the Nucleation and Growth Mechanisms in the Electrodeposition of Micro- and Nanostructured Cu2O Thin Films. The Journal of Physical Chemistry C, 115(43), 21373-21382. doi:10.1021/jp208535

Experiences in the development of didactic videos in remote and hybrid teaching: the case of Materials Science laboratory practices

[EN] The COVID-19 pandemics greatly affected teaching methods and tools. In the last two years the teaching method switched from face-to-face to online or hybrid and later on, to face-to-face again. This paper presents the results of the experience carried out in the lab-sessions of Materials Science subject within the Degree in Engineering in Industrial Design and Product Development, taught at the Higher Technical School of Design Engineering of the Universitat politècnica de València. The aim of this work is to develop an audio-visual teaching tool to be used during the course, to aid students understand the experimental procedures and the use of laboratory equipment in order to increase their academic performance. For this purpose, the obligatory didactic videos employed to undertake the laboratory session during the pandemics, when the students participated remotely, were processed and employed in a shorter version as an optional TIC tool during the last academic course. The student satisfaction towards the utility of didactic videos was measured by using an individual questionnaire. A comparison between the academic performance during pre- and post-pandemics was performed, as well.[ES] La pandemia de COVID-19 afectó en gran medida a los métodos y herramientas de aprendizaje. En los dos últimos años se pasó de la modalidad de enseñanza presencial a online o híbrida y, posteriormente, nuevamente a la presencial. Este artículo presenta los resultados de la experiencia realizada en las prácticas de la asignatura Ciencia de los Materiales del Grado en Ingeniería en Diseño Industrial y Desarrollo de Productos, impartida en la Escuela Técnica Superior de Ingeniería del Diseño de la Universitat Politècnica de València. El objetivo de este trabajo es desarrollar una herramienta didáctica audiovisual a utilizar durante el curso, para ayudar a los estudiantes a comprender los procedimientos experimentales y el uso de equipos de laboratorio con el objetivo de incrementar su rendimiento académico. Para ello se procesaron los videos didácticos desarrollados para realizar la sesión de laboratorio durante la pandemia, cuando los estudiantes participaban de forma no presencial, y se emplearon en una versión más corta como herramienta TIC opcional durante el último curso académico. La satisfacción de los estudiantes con la utilidad de los videos didácticos se midió mediante un cuestionario individual. También se realizó una comparación entre el rendimiento académico durante la pre-pandemia y post-pandemia.Pruna, AI.; Klyatskina Rusinovich, E.; Vicente Escuder, A.; Rupérez Moreno, MJ. (2022). Experiencias en el desarrollo de videos didácticos en las enseñanzas remota e híbrida: el caso de las prácticas de laboratorio de Ciencia de los Materiales. Editorial Universitat Politècnica de València. 1136-1143. https://doi.org/10.4995/INRED2022.2022.159061136114

Improving the properties of Cu2O/ZnO heterojunction for photovoltaic application by graphene oxide

[EN] A p-Cu2O/n-ZnO heterojunction grown on fluorine-doped tin oxide (FTO) substrate is reported by a combined low-cost approach employing tape-casting of ZnO layer and subsequent electrochemical deposition of Cu2O layer. Graphene oxide (GO) nanosheets were employed as nanofiller for the ZnO matrix. Moreover, a ZnO buffer layer was inserted at the interface between the Cu2O and ZnO layers. The morphological, structural and photoelectrical characteristics of these heterojunction layers were investigated by field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), Raman spectroscopy and photoelectrical current-voltage measurements. The results confirmed that the morphology and structure of ZnO layer were affected by the incorporation of GO nanosheets while the presence of buffer layer influenced the growth of Cu2O layer. This work shows the addition of GO and the use of ZnO buffer layer represent a viable approach towards improving the photoelectrical properties of the Cu2O/ZnO heterojunction cell.Financial support from Escuela Politecnica Nacional, Ecuador (project number PIMI 15-09) and Secretaria de Education Superior, Ciencia, Tecnologia e Innovation (SENESCYT) and Romanian National Authority for Scientific Research and Innovation, Romania CNCS - UEFISCDI (project number PN-III-P1-1.1-TE-2016-1544) is gratefully acknowledged.Rosas-Laverde, NM.; Pruna, AI.; Busquets Mataix, DJ.; Marí, B.; Cembrero Cil, J.; Salas Vicente, F.; Orozco-Messana, J. (2018). Improving the properties of Cu2O/ZnO heterojunction for photovoltaic application by graphene oxide. Ceramics International. 44(18):23045-23051. https://doi.org/10.1016/j.ceramint.2018.09.107S2304523051441

Experiencias y conclusiones en el desarrollo y validación de instrumentos de evaluación enfocados a la adquisición de la competencia transversal ‘CT13 Instrumental Específica’ en asignaturas de Ingeniería Mecánica

[EN] This paper presents the results of the experience carried out in the lab-sessions of several subjects of Mechanical Engineering. The aim of this work is to find a common methodology focused on the acquisition and evaluation of the Specific Instrumental Transversal Competence (CT13 in the UPV institutional project). The work has been applied in two types of lab-sessions: computer lab and laboratory. The instrumentation used in each of them has a different nature, while the former is focused on the use and comprehension of a numerical calculation software, in the latter the students must understand the management and purpose of some experimental measurement equipments. In the computer sessions, after an accompanied learning, the students must carry out and justify the steps followed in solving a numerical problem. The evaluation takes into account the level of adequacy of the steps followed throughout the process. In the laboratory practices, the students must demonstrate the ability to correctly select the proper equipment based on the parameter to be measured as well as to define the sequence of treatments in the measurement process. The measurement of the level of acquisition of the CT13 is done through an individual questionnaire.[ES] En este trabajo se presentan los resultados de la experiencia llevada a cabo en las prácticas de diversas asignaturas de Ingeniería Mecánica. El objetivo final es encontrar una metodología unificada enfocada a la adquisición y evaluación de la Competencia Transversal Instrumental Específica (CT13 en el proyecto institucional de la UPV).Se ha trabajado con dos tipos de prácticas: informáticas y de laboratorio. La instrumentación empleada en cada una de ellas tiene distinta naturaleza, mientras las primeras están enfocadas al manejo de un programa de cálculo numérico, en las segundas los estudiantes deben comprender el manejo y la finalidad de diversos equipos de medida experimental.En las prácticas informáticas los alumnos, tras un aprendizaje acompañado, deben ser capaces de realizar y justificar los pasos seguidos en la resolución de un problema numérico. En la evaluación se tiene en cuenta el nivel de adecuación de los pasos seguidos a lo largo del proceso. En las prácticas de laboratorio los alumnos deben demostrar la capacidad de seleccionar correctamente el equipo adecuado en función del parámetro a medir, así como definir la secuencia de tratamientos en el proceso experimental. La medida del nivel de adquisición de la CT13 se realiza con un cuestionario individual.Los autores agradecen la financiación recibida del Vicerrectorado de Estudios, Calidad y Acreditación, el Vicerrectorado de Recursos Digitales y Documentación (proyecto PIME B/19-20/165) y el Instituto de Ciencias de la Educación de la Universitat Politècnica de València (EICE INTEGRAL).Pedrosa Sanchez, AM.; Besa Gonzálvez, AJ.; Rupérez Moreno, MJ.; Sánchez Orgaz, EM.; Giner Navarro, J.; Martinez Sanchis, S.; Vila Tortosa, MP.... (2021). Experiencias y conclusiones en el desarrollo y validación de instrumentos de evaluación enfocados a la adquisición de la competencia transversal ‘CT13 Instrumental Específica’ en asignaturas de Ingeniería Mecánica. En IN-RED 2021: VII Congreso de Innovación Edicativa y Docencia en Red. Editorial Universitat Politècnica de València. 1521-1532. https://doi.org/10.4995/INRED2021.2021.13771OCS1521153

Tailoring the Performance of Graphene Aerogels for Oil/Organic Solvent Separation by 1-Step Solvothermal Approach

Ultra-light eco-friendly graphene oxide (GO)-based aerogels are reported by simple one-step solvothermal self-assembly. The effect of varying parameters such as C/O ratio of GO; reducing agent amount; temperature; and duration on the properties of the aerogels was studied. The structural and vibrational features and hydrophobic surface properties of the obtained aerogels were obtained by XRD; FTIR; XPS; Raman; SEM; and contact angle measurements. The effect of synthesis conditions on the engine oil and organic solvent absorption properties was assessed. The results indicated that the lower the C/O ratio of GO, the better the absorption properties, with the best performance for oil uptake reaching 86 g g−1. The obtained results indicate the approach based on ice-templating and the tailoring of oxygen content in GO make the resulting aerogels potential candidates for use in oil spill and organic solvent treatments

Supercapacitance of Single-Walled Carbon Nanotubes-Polypyrrole Composites

The composites based on carbon nanotubes (CNTs) and conducting polymers (CPs) are promising materials for supercapacitor devices due to their unique nanostructure that combines the large pseudocapacitance of the CPs with the fast charging/discharging double-layer capacitance and excellent mechanical properties of the CNTs. Here, we report a new electrochemical method to obtain polypyrrole (PPY)/single-walled carbon nanotube (SWCNT) composites. In the first step, the SWCNTs are covalently functionalized with monomeric units of pyrrole by esterification of acyl chloride functionalized SWCNTs and N-(6-hydroxyhexyl)pyrrole. In the second step, the PPY/SWCNTs composites are obtained by copolymerizing the pyrrole monomer with the pyrrole units grafted on SWCNTs surface using controlled potential electrolysis. The composites were further characterized by cyclic voltammetry and electrochemical impedance spectroscopy. The results showed good electrochemical charge storage properties for the synthesized composites based on PPY and SWCNTs covalently functionalized with pyrrole units making them promising electrode materials for high power supercapacitors