LIVIVO - Search results -

Search results

Result 1 - 10 of total 22

Search options

Article ; Online: Conference on Artificial Photosynthesis and Green Catalysis

Jing Gao / Lukas Pfeifer / Paula Dias / Adélio Mendes / Michael Graetzel

CHIMIA, Vol 77, Iss

2023 Volume 12

Keywords	Chemistry ; QD1-999
Language	German
Publishing date	2023-12-01T00:00:00Z
Publisher	Swiss Chemical Society
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

Full text online

Full text

Inter-library loan at ZB MED

Your chosen title can be delivered directly to ZB MED Cologne location if you are registered as a user at ZB MED Cologne.

Article ; Online: Selection of the ultimate perovskite solar cell materials and fabrication processes towards its industrialization

Cristina O. Teixeira / Diogo Castro / Luísa Andrade / Adélio Mendes

Energy Science & Engineering, Vol 10, Iss 4, Pp 1478-

A review

2022 Volume 1525

Abstract: Abstract Hybrid organic–inorganic perovskite materials have become one of the most studied classes of light‐harvesting materials due to their exceptional properties such as high light absorption, long carrier diffusion lengths, bandgap tuning and defect ... ...

Abstract	Abstract Hybrid organic–inorganic perovskite materials have become one of the most studied classes of light‐harvesting materials due to their exceptional properties such as high light absorption, long carrier diffusion lengths, bandgap tuning and defect tolerance. Since 2009 that the scientific community has been working on improving the power conversion efficiency (PCE) of perovskite solar cell devices, reaching now an impressive value of 25.5%. Moreover, efficiencies over 18% are often reported by several authors. Since the efficiency goal is almost fulfilled, the scientific community is currently addressing five challenges, with the ultimate objective to make this technology competitive and turn it commercial; these challenges are cost, stability, upscaling, safety and environmental impact. Given the astonishing progresses reached during the past decade and the numerous research groups working to the same goal, it is a matter of time until commercial perovskite solar devices become a reality. In this review work, the most recent achievements regarding this purpose are put together and compared, so as to suggest the most suitable perovskite solar fabrication processes and materials to produce commercial devices.
Keywords	commercialization ; costs ; environmental impact ; perovskite solar cell ; stability ; upscaling ; Technology ; T ; Science ; Q
Subject code	600
Language	English
Publishing date	2022-04-01T00:00:00Z
Publisher	Wiley
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

Full text online

Full text

Inter-library loan at ZB MED

Your chosen title can be delivered directly to ZB MED Cologne location if you are registered as a user at ZB MED Cologne.

Article ; Online: Cellulose-Based Carbon Molecular Sieve Membranes for Gas Separation

Tiago Araújo / Gabriel Bernardo / Adélio Mendes

Molecules, Vol 25, Iss 3532, p

A Review

2020 Volume 3532

Abstract: In the field of gas separation and purification, membrane technologies compete with conventional purification processes on the basis of technical, economic and environmental factors. In this context, there is a growing interest in the development of ... ...

Abstract	In the field of gas separation and purification, membrane technologies compete with conventional purification processes on the basis of technical, economic and environmental factors. In this context, there is a growing interest in the development of carbon molecular sieve membranes (CMSM) due to their higher permeability and selectivity and higher stability in corrosive and high temperature environments. However, the industrial use of CMSM has been thus far hindered mostly by their relative instability in the presence of water vapor, present in a large number of process streams, as well as by the high cost of polymeric precursors such as polyimide. In this context, cellulosic precursors appear as very promising alternatives, especially targeting the production of CMSM for the separation of O 2 /N 2 and CO 2 /CH 4 . For these two gas separations, cellulose-based CMSM have demonstrated performances well above the Robeson upper bound and above the performance of CMSM based on other polymeric precursors. Furthermore, cellulose is an inexpensive bio-renewable feed-stock highly abundant on Earth. This article reviews the major fabrication aspects of cellulose-based CMSM. Additionally, this article suggests a new tool to characterize the membrane performance, the Robeson Index. The Robeson Index, θ, is the ratio between the actual selectivity at the Robeson plot and the corresponding selectivity—for the same permeability—of the Robeson upper bound; the Robeson Index measures how far the actual point is from the upper bound.
Keywords	membranes ; cellulose ; carbon molecular sieve membranes ; Robeson Index ; Organic chemistry ; QD241-441
Subject code	660
Language	English
Publishing date	2020-08-01T00:00:00Z
Publisher	MDPI AG
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

Full text online

Full text

Inter-library loan at ZB MED

Your chosen title can be delivered directly to ZB MED Cologne location if you are registered as a user at ZB MED Cologne.

Article ; Online: Hydrogen production via aqueous-phase reforming for high-temperature proton exchange membrane fuel cells - a review [version 3; peer review

Paulo Ribeirinha / Paranjeet Lakhtaria / Saara Viik / Werneri Huhtinen / Adélio Mendes / José Sousa

Open Research Europe, Vol

2 approved]

2022 Volume 1

Abstract: Aqueous-phase reforming (APR) can convert methanol and other oxygenated hydrocarbons to hydrogen and carbon dioxide at lower temperatures when compared with the corresponding gas phase process. APR favours the water-gas shift (WGS) reaction and inhibits ... ...

Abstract	Aqueous-phase reforming (APR) can convert methanol and other oxygenated hydrocarbons to hydrogen and carbon dioxide at lower temperatures when compared with the corresponding gas phase process. APR favours the water-gas shift (WGS) reaction and inhibits alkane formation; moreover, it is a simpler and more energy efficient process compared to gas-phase steam reforming. For example, Pt-based catalysts supported on alumina are typically selected for methanol APR, due to their high activity at temperatures of circa 200°C. However, non-noble catalysts such as nickel (Ni) supported on metal-oxides or zeolites are being investigated with promising results in terms of catalytic activity and stability. The development of APR kinetic models and reactor designs is also being addressed to make APR a more attractive process for producing in situ hydrogen. This can also lead to the possibility of APR integration with high-temperature proton exchange membrane fuel cells. The integration can result into increased overall system efficiency and avoiding critical issues faced in the state-of-the-art fuel cells integrated with methanol steam reforming.
Keywords	Aqueous-phase reforming ; methanol ; hydrogen ; catalyst ; fuel cell ; PEMFC ; eng ; Science ; Q ; Social Sciences ; H
Subject code	660
Language	English
Publishing date	2022-03-01T00:00:00Z
Publisher	F1000 Research Ltd
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

Full text online

Full text

Inter-library loan at ZB MED

Your chosen title can be delivered directly to ZB MED Cologne location if you are registered as a user at ZB MED Cologne.

Article ; Online: A Systematic Performance History Analysis of a Chlor-Alkali Membrane Electrolyser under Industrial Operating Conditions

Filipa Franco / Jorge Prior / Svetlozar Velizarov / Adélio Mendes

Applied Sciences, Vol 9, Iss 2, p

2019 Volume 284

Abstract: The history of the potential and electrical current evolution of an industrial chlor-alkali membrane electrolyser is a powerful tool to track its operational efficiency progress over time and for deciding the required maintenance instants. For this ... ...

Abstract	The history of the potential and electrical current evolution of an industrial chlor-alkali membrane electrolyser is a powerful tool to track its operational efficiency progress over time and for deciding the required maintenance instants. For this reason, the performance of a dedicated industrial NaCl electrolyser was systematically analysed as a function of its service time for about 8 years, recording the cell potential versus current density. The documented potential values were normalized taking into account the initial current density, which allowed to reduce data scattering due to small fluctuations of the current density values. The ohmic overpotential contribution, associated to the ion-exchange membranes, showed an average relative error smaller than 3% and the activation overpotential, related to the electrodes’ performance, displayed an average relative error of 6%. Thus, the proposed approach enables rigorous assessing of the performance of industrial chlor-alkali membrane electrolysers for adequate scheduling of their maintenance, which leads to significant operational and economic improvements of the chlor-alkali process.
Keywords	chlor-alkali membrane electrolyser ; energy consumption ; overpotential ; service time ; Technology ; T ; Engineering (General). Civil engineering (General) ; TA1-2040 ; Biology (General) ; QH301-705.5 ; Physics ; QC1-999 ; Chemistry ; QD1-999
Subject code	670
Language	English
Publishing date	2019-01-01T00:00:00Z
Publisher	MDPI AG
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

Full text online

Full text

Inter-library loan at ZB MED

Your chosen title can be delivered directly to ZB MED Cologne location if you are registered as a user at ZB MED Cologne.

Article ; Online: Project and Implementation of an Educational Large-Scale Water Distillation Unit with a Closed-Circuit Condenser

Luís Carlos Matos / Ana Eulálio / Tiago Antunes / José Miguel Loureiro / Alexandre Ferreira / Adélio Mendes

Sustainability, Vol 12, Iss 3239, p

2020 Volume 3239

Abstract: Water is one of the scarcest resources in the world, and it is becoming rarer fast, year after year. Chemical engineers are particularly suited to addressing the challenges of saving water and producing more fresh water. Proper education is then critical ...

Abstract	Water is one of the scarcest resources in the world, and it is becoming rarer fast, year after year. Chemical engineers are particularly suited to addressing the challenges of saving water and producing more fresh water. Proper education is then critical to prepare them for the upcoming decades. All student laboratories need distilled water, which is typically produced using commercial distillation units, which consume up to 70 L of fresh water per liter of distillated water. This work reports the design, construction, optimization, and operation of a water distillation unit that produces 10 liters per hour at 4 µS∙cm −1 and wastes no fresh water. Developed by a committed team made up of students, lab technicians, and instructors, this unit saves ca. 550 m 3 of fresh water annually while spending less electrical power.
Keywords	distilled water ; heat transfer ; distillation ; automation and control ; chemical engineering education ; Environmental effects of industries and plants ; TD194-195 ; Renewable energy sources ; TJ807-830 ; Environmental sciences ; GE1-350
Subject code	333 ; 690
Language	English
Publishing date	2020-04-01T00:00:00Z
Publisher	MDPI AG
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

Full text online

Full text

Inter-library loan at ZB MED

Your chosen title can be delivered directly to ZB MED Cologne location if you are registered as a user at ZB MED Cologne.

Article ; Online: Graded Morphologies and the Performance of PffBT4T-2OD:PC 71 BM Devices Using Additive Choice

Hugo Gaspar / Andrew J. Parnell / Gabriel E. Pérez / Júlio C. Viana / Stephen M. King / Adélio Mendes / Luiz Pereira / Gabriel Bernardo

Nanomaterials, Vol 11, Iss 3367, p

2021 Volume 3367

Abstract: The impact of several solvent processing additives (1-chloronaphthalene, methylnaphthalene, hexadecane, 1-phenyloctane, and p-anisaldehyde), 3% v / v in o-dichlorobenzene, on the performance and morphology of poly[(5,6-difluoro-2,1,3-benzothiadiazol-4,7- ... ...

Abstract	The impact of several solvent processing additives (1-chloronaphthalene, methylnaphthalene, hexadecane, 1-phenyloctane, and p-anisaldehyde), 3% v / v in o-dichlorobenzene, on the performance and morphology of poly[(5,6-difluoro-2,1,3-benzothiadiazol-4,7-diyl)-alt-(3,3‴-di(2-octyldodecyl)-2,2′,5′,22033,5″,2‴-quaterthiophen-5,5‴-diyl)] (PffBT4T-2OD):[6,6]-phenyl-C71-butyric acid methyl ester (PC 71 BM)-based polymer solar cells was investigated. Some additives were shown to enhance the power conversion efficiency (PCE) by ~6%, while others decreased the PCE by ~17–25% and a subset of the additives tested completely eliminated any power conversion efficiency and the operation as a photovoltaic device. Grazing-Incidence Wide Angle X-ray Scattering (GIWAXS) revealed a clear stepwise variation in the crystallinity of the systems when changing the additive between the two extreme situations of maximum PCE (1-chloronaphthalene) and null PCE (hexadecane). Small-Angle Neutron Scattering (SANS) revealed that the morphology of devices with PCE ~0% was composed of large domains with correlation lengths of ~30 nm, i.e., much larger than the typical exciton diffusion length (~12 nm) in organic semiconductors. The graded variations in crystallinity and in nano-domain size observed between the two extreme situations (1-chloronaphthalene and hexadecane) were responsible for the observed graded variations in device performance.
Keywords	Organic photovoltaics ; bulk-heterojunction morphology ; additives ; PffBT4T-2OD ; Chemistry ; QD1-999
Language	English
Publishing date	2021-12-01T00:00:00Z
Publisher	MDPI AG
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

Full text online

Full text

Inter-library loan at ZB MED

Your chosen title can be delivered directly to ZB MED Cologne location if you are registered as a user at ZB MED Cologne.

Article: TiO₂-coated window for facilitated gas evolution in PEC solar water splitting

Miranda, Sérgio / António Vilanova / Tânia Lopes / Adélio Mendes

RSC advances. 2017 June 07, v. 7, no. 47

2017

Abstract: Photoelectrochemical (PEC) cells for water splitting generally have a transparent front window for the sunlight to reach the surface of the photoelectrode or tandem photoelectrode. The overall efficiency of a PEC system for solar hydrogen production is ... ...

Abstract	Photoelectrochemical (PEC) cells for water splitting generally have a transparent front window for the sunlight to reach the surface of the photoelectrode or tandem photoelectrode. The overall efficiency of a PEC system for solar hydrogen production is strongly affected by the evolved gases that get trapped in the front window. This negative effect is clearly observed when the PEC cells are placed in tilted positions to maximize light harvesting. Titanium dioxide coatings become superhydrophilic when exposed to UV light, facilitating the gas bubbles to slip up. The present study focuses on the development of a thin TiO₂ coating to minimize the adhesion of the evolved bubbles in the front window of PEC cells, thereby maximizing its transparency. Highly transparent, crack-free, and stable thin films of TiO₂ were prepared by spin coating followed by sintering at 465 °C for 45 min. A water contact angle (WCA) of 0° was obtained after irradiating the surface of the sample for 30 min with UV-light (365 nm, 2 W m⁻²), confirming the superhydrophilic behaviour. The irradiance loss during the evolution of H₂/O₂ was assessed using a silicon PV cell; the cell, tilted at 45° and equipped with a TiO₂-coated glass window, showed ca. 10% higher irradiance as compared to the uncoated glass window cell for both hydrogen and oxygen evolutions, whereas no significant differences were observed when the cells were vertically placed.
Keywords	adhesion ; bubbles ; coatings ; contact angle ; gases ; glass ; hydrogen ; hydrogen production ; hydrophilicity ; light intensity ; oxygen ; silicon ; solar radiation ; titanium dioxide ; ultraviolet radiation
Language	English
Dates of publication	2017-0607
Size	p. 29665-29671.
Publishing place	The Royal Society of Chemistry
Document type	Article
ISSN	2046-2069
DOI	10.1039/c7ra01923h
Database	NAL-Catalogue (AGRICOLA)

Order via subito

This service is chargeable due to the Delivery terms set by subito. Orders including an article and supplementary material will be classified as separate orders. In these cases, fees will be demanded for each order.

Inter-library loan at ZB MED

Your chosen title can be delivered directly to ZB MED Cologne location if you are registered as a user at ZB MED Cologne.

Article: Pre-fabricated, environmentally friendly and energy self-sufficient single-family house in Kenya

Samani, Pouya / Adélio Mendes / Nuno Correia / Vítor Leal

Journal of cleaner production. 2017 Jan. 20, v. 142

2017

Abstract: This work provides a comprehensive approach for electrification of rural areas of Kenya through taking into account both energy demand and supply sides. Toward this, a pre-fabricated composite building is assessed by defining two different levels of ... ...

Abstract	This work provides a comprehensive approach for electrification of rural areas of Kenya through taking into account both energy demand and supply sides. Toward this, a pre-fabricated composite building is assessed by defining two different levels of energy needs and calculating annual cooling and heating energy demands to keep the occupants within the comfort temperature range. Consequently, four passive cooling techniques (shading, natural ventilation, cool painting and increased thickness of interior gypsum plaster) are applied to decrease the cooling energy demand. Afterwards, a stand-alone photovoltaic (SAPV) system is designed through sizing of the main components as well as determining the optimum tilt angle and azimuth for the PV array. Finally, four PV technologies (monocrystalline silicon (mono-Si), polycrystalline silicon (poly-Si), cadmium telluride (CdTe) and copper indium selenide (CIS)) were assessed for the designed SAPV system and compared in terms of environmental impact and cost and CIS demonstrated the best performance in all criteria. The results highlight a reduction of about 84% in cooling energy demand through combining all passive cooling techniques originating a house displaying passive behavior. Moreover, the SAPV system proves to be a feasible solution with significant lower cost and greenhouse gas (GHG) emissions in comparison with alternative solutions. The results also outline the importance of the loss of load probability (LLP) in designing SAPV systems indicating a sudden increase in required power of array for LLPs less than 2%.
Keywords	cooling ; energy ; environmental impact ; greenhouse gas emissions ; greenhouse gases ; gypsum ; heat ; natural ventilation ; plaster ; probability ; rural areas ; rural electrification ; shade ; silicon ; supply balance ; temperature ; Kenya
Language	English
Dates of publication	2017-0120
Size	p. 2100-2113.
Publishing place	Elsevier Ltd
Document type	Article
ISSN	0959-6526
DOI	10.1016/j.jclepro.2016.11.073
Database	NAL-Catalogue (AGRICOLA)

Order via subito

Inter-library loan at ZB MED

Your chosen title can be delivered directly to ZB MED Cologne location if you are registered as a user at ZB MED Cologne.

Article ; Online: Influence of the ZrO 2 Crystalline Phases on the Nature of Active Sites in PdCu/ZrO 2 Catalysts for the Methanol Steam Reforming Reaction—An In Situ Spectroscopic Study

Daniel Ruano / Beatriz M. Pabón / Càtia Azenha / Cecilia Mateos-Pedrero / Adélio Mendes / Virginia Pérez-Dieste / Patricia Concepción

Catalysts, Vol 10, Iss 1005, p

2020 Volume 1005

Abstract: In this work, the electronic properties of the metal sites in cubic and monoclinic ZrO 2 supported Pd and PdCu catalysts have been investigated using CO as probe molecule in in-situ IR studies, and the surface composition of the outermost layers has been ...

Abstract	In this work, the electronic properties of the metal sites in cubic and monoclinic ZrO 2 supported Pd and PdCu catalysts have been investigated using CO as probe molecule in in-situ IR studies, and the surface composition of the outermost layers has been studied by APXPS (Ambient Pressure X-ray Photoemission Spectroscopy). The reaction products were followed by mass spectrometry, making it possible to relate the chemical properties of the catalysts under reaction conditions with their selectivity. Combining these techniques, it has been shown that the structure of the support (monoclinic or cubic ZrO 2 ) affects the metal dispersion, mobility, and reorganization of metal sites under methanol steam reforming (MSR) conditions, influencing the oxidation state of surface metal species, with important consequences in the catalytic activity. Correlating the mass spectra of the reaction products with these spectroscopic studies, it was possible to conclude that electropositive metal species play an imperative role for high CO 2 and H 2 selectivity in the MSR reaction (less CO formation).
Keywords	APXPS ; Near Ambient Pressure-X-ray Photoelectron Spectroscopy ; X-ray spectroscopy ; in situ characterization ; copper ; palladium ; Chemical technology ; TP1-1185 ; Chemistry ; QD1-999
Subject code	540
Language	English
Publishing date	2020-09-01T00:00:00Z
Publisher	MDPI AG
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

Full text online

Full text

Inter-library loan at ZB MED

Your chosen title can be delivered directly to ZB MED Cologne location if you are registered as a user at ZB MED Cologne.

To top

Full text online

More links

Kategorien

Inter-library loan at ZB MED

Full text online

More links

Kategorien

Inter-library loan at ZB MED

Full text online

More links

Kategorien

Inter-library loan at ZB MED

Full text online

More links

Kategorien

Inter-library loan at ZB MED

Full text online

More links

Kategorien

Inter-library loan at ZB MED

Full text online

More links

Kategorien

Inter-library loan at ZB MED

Full text online

More links

Kategorien

Inter-library loan at ZB MED

More links

Kategorien

Order via subito

Inter-library loan at ZB MED

More links

Kategorien

Order via subito

Inter-library loan at ZB MED

Full text online

More links

Kategorien

Inter-library loan at ZB MED