Green economy and waste management: An inevitable plan for materials science

LA/P/0037/2020 UIDP/50025/2020 UIDB/50025/2020Covid is giving us many lessons among which one must be to realize that this is the time to act for sustainable future. The smart world around us has made it inevitable to have an alarming situation regarding the uncontrolled growth of waste products such as plastic and electronic wastes. Both are immense threats to the health of human, wildlife and environment, that eventually affect the societal and economic structures as evident from recent Covid-crisis. The proper management of these wastes and innovating ideas for new sustainable technologies are the need of the hour. Circular economy act with green technology (green economy) is the way to tackle this challenge. Current perspective presents the overview of the scenario regarding these burgeoning issues and demonstrates some measures that are taken or being considered to depend on to come out of them.publishersversionpublishe

Memristors using solution-based IGZO nanoparticles

Solution-based indium-gallium-zinc oldde (IGZO) nanoparticles deposited by spin coating have been investigated as a resistive switching layer in metal-insulator-metal structures for nonvolatile memory applications. Optimized devices show a bipolar resistive switching behavior, low programming voltages of +/- 1 V, on/off ratios higher than 10, high endurance, and a retention time of up to 104 s. The better performing devices were achieved with annealing temperatures of 200 degrees C and using asymmetric electrode materials of titanium and silver. The physics behind the improved switching properties of the devices is discussed in terms of the oxygen deficiency of IGZO. Temperature analysis of the conductance states revealed a nonmetallic filamentary conduction. The presented devices are potential candidates for the integration of memory functionality into low-cost System-on-Panel technology.National Funds through FCT - Portuguese Foundation for Science and Technology [UID/CTM/50025/2013, SFRH/BDP/99136/2013]; FEDER [POCI-01-0145-FEDER-007688]info:eu-repo/semantics/publishedVersio

A class of multifunctional smart energy materials

Funding Information: S. Goswami would like to thank to Lisboa2020 Programme, Centro 2020 programme, Portugal 2020, European Union, through the European Social Fund who supported LISBOA-05-3559-FSE-000007 and CENTRO-04-3559-FSE-000094 operations as well as to Fundação para a Ciência e Tecnologia (FCT) and Agência Nacional de Inovação (ANI). Publisher Copyright: © 2022 The AuthorsPolymer material provides significant advantages over the conventional inorganic material-based electronics due to its attractive features including miniaturized dimension and feasible improvisations in physical properties through molecular design and chemical synthesis. In particular, conjugate polymers are of great interest because of their ability to control the energy gap and electronegativity through molecular design that has made possible the synthesis of conducting polymers with a range of ionization potentials and electron affinities. Polyaniline (PANI) is one of the most popular conjugated polymers that has been widely explored so far for its multifunctionality in diverse potential applications. This review is focusing on the recent advances of PANI for smart energy applications including supercapacitors, batteries, solar cells and nanogenerators and the development in its synthesis, design, and fabrication processes. A details investigation on the different types of chemical process has been discussed to fabricate PANI in nanostructures, film, and composites form. The paper includes several studies which are advantageous for understanding: the unique chemical and physical properties of this polymer; and the easily tunable electrical properties along with its redox behavior; and different processes to develop nanostructures, film, or bulk form of PANI that are useful to derive its applicability in smart objects or devices.publishersversionpublishe

Driving nanozymes towards stereochemical recognition: application to biomolecules of interest in health

National Foundation for Science and Technology, I.P., FCT, with reference SFRH/BD/130107/2017info:eu-repo/semantics/publishedVersio

Multifunctional ZnO – based Thin Films by Sol-Gel Method

The paper presents the crystalline structure, morphology, optical transmittance, electrical properties and room temperature photoreduction-ozone oxidation properties of some Al-doped ZnO thin films prepared by sol-gel method. The investigated films are high transparent (85-95% within the visible and near IR wavelength region), high conductive (2.9 10-3 Ω cm) and have a reversible photoreduction-oxidation response

SERS-based biosensors for on-site determination of pancreatic cancer biomarkers

Yuselis Castaño-Guerrero acknowledges Fundação para a Ciência e a Tecnologia (FCT) her PhD Grant (SFRH/BD/145590/2019)info:eu-repo/semantics/publishedVersio

Metal oxide-based photocatalytic paper: A green alternative for environmental remediation

The interest in advanced photocatalytic technologies with metal oxide-based nanomaterials has been growing exponentially over the years due to their green and sustainable characteristics. Photocatalysis has been employed in several applications ranging from the degradation of pollutants to water splitting, CO2 and N2 reductions, and microorganism inactivation. However, to maintain its eco-friendly aspect, new solutions must be identified to ensure sustainability. One alternative is creat-ing an enhanced photocatalytic paper by introducing cellulose-based materials to the process. Paper can participate as a substrate for the metal oxides, but it can also form composites or membranes, and it adds a valuable contribution as it is environmentally friendly, low-cost, flexible, recyclable, lightweight, and earth abundant. In term of photocatalysts, the use of metal oxides is widely spread, mostly since these materials display enhanced photocatalytic activities, allied to their chemical stability, non-toxicity, and earth abundance, despite being inexpensive and compatible with low-cost wet-chemical synthesis routes. This manuscript extensively reviews the recent developments of using photocatalytic papers with nanostructured metal oxides for environmental remediation. It focuses on titanium dioxide (TiO2) and zinc oxide (ZnO) in the form of nanostructures or thin films. It discusses the main characteristics of metal oxides and correlates them to their photocatalytic activity. The role of cellulose-based materials on the systems’ photocatalytic performance is extensively discussed, and the future perspective for photocatalytic papers is highlighted.publishersversionpublishe

Microwave-Assisted Hydrothermal Synthesis of Zn2SnO4 Nanostructures for Photocatalytic Dye Degradation

Zinc-tin oxide (ZTO) nanostructures appear as one of the most promising material systems for a new generation of nanodevices. In this work, a microwave-assisted hydrothermal synthesis to produce different shapes of Zn2SnO4 nanostructures (nanoparticles, octahedrons and nanoplates) is presented. Reproducible and homogeneous results were obtained with the advantage of reducing up to 20 h the synthesis time when compared to using a conventional oven. Furthermore, the photocatalytic activity of the Zn2SnO4 nanostructures in the degradation of rhodamine B under UV light was studied. Zn2SnO4 nanoparticles demonstrated better performance with >90% of degradation being achieved in 2.5 h.publishersversionpublishe

Photocatalytic Activity of TiO2 Nanostructured Arrays Prepared by Microwave-Assisted Solvothermal Method

The use of metal-oxide-semiconductor nanostructures as photocatalytic materials has been an area of intense research over the last decade, and in this field, titanium dioxide (TiO2) receives much attention. TiO2 is an attractive material since it is stable, insoluble, non-toxic, resistant to corrosion and relatively inexpensive. In this chapter, we will demonstrate the influence of different solvents on the synthesis of TiO2 nanostructures considering a solvothermal method assisted by microwave radiation and their photocatalytic behaviour. The TiO2 nanostructured arrays were synthesized on seeded polyethylene naphthalate (PEN) substrates with different solvents: water, 2 – propanol, ethanol and methanol. TiO2 thin films deposited by spin-coating were used as seed layer for the nanostructures growth. Structural characterization of the microwave synthesized materials has been carried out by scanning electron microscopy (SEM) and X-Ray diffraction (XRD). The optical properties have also been investigated. The TiO2 nanostructures arrays were tested as photocatalytic agents in the degradation of pollutant dyes like methylene blue (MB) in the presence of UV radiation. Expressive differences between the different solvents were detected, in which methanol demonstrated higher MB degradation for the conditions tested

Nanomaterials and Biosensors for health application

Akmaral Suleimenova gratefully acknowledges Fundação para a Ciência e a Tecnologia for the PhD grant PD/BD/142776/2018, within the MIT Portugal Programinfo:eu-repo/semantics/publishedVersio