Editor’s Choice – Catalytic and Photothermo-catalytic Applications of TiO2-CoOx Composites

Author(s):Roberto Fiorenza, Marcello Condorelli, Luisa D’Urso, Giuseppe Compagnini, Marianna Bellardita, Leonardo Palmisano and Salvatore Scirè*

Volume 1, Issue 1, 2020

Page: [3 – 15]

Pages: 13

DOI: 10.2174/2665976X01666200219113505

Abstract

Background: The necessity to have green and sustainable industrial processes has promoted new technologies for air and water purification together with the research of new energy sources. In this contest, the TiO2-based photocatalysis can be considered a promising route for both environmental applications and hydrogen production through water splitting.

Objective: In this work, we have investigated the photocatalytic performance of TiO2-CoOx composites on both photooxidation and photoreduction reactions. Specifically, we have compared the performance of the composites in the thermo-catalytic, photo-catalytic and photothermal-catalytic oxidation of ethanol chosen as model volatile organic compound (VOC) and in the photocatalytic hydrogen production by simulated solar light from aqueous solution of ethanol.

Methods: The samples were prepared with a simple impregnation method, and were characterized by Scanning Electron (SEM) and Transmission Electron (TEM) microscopies, X-ray powder diffraction (XRD), N2 adsorption-desorption measurements, Temperature Programmed Reduction in hydrogen (H2- TPR) and X-ray Photoelectron (XPS), Raman, UV-Vis Diffuse Reflectance (UV-Vis DRS) and Photoluminescence (PL) spectroscopies. The catalytic and photocatalytic activity were carried out on pyrex reactors irradiated with a solar lamp and analyzing the reactions products through gas chromatography.

Results: The presence and the amount of cobalt oxide were found crucial in determining the performance of the TiO2-based composites for both the catalytic and photocatalytic processes. In particular, the addition of 1 weight percent of CoOx led to the best performance in the photocatalytic processes, whereas a higher amount was beneficial in the thermo-catalytic tests. The multi-catalytic approach based on the synergistic effect of photocatalysis and thermocatalysis in the presence of the TiO2-1%CoOx sample allowed the temperature necessary to obtain 50% ethanol conversion and 50% yield in CO2 to be reduced by 40°C and 50°C, respectively. The same sample was also the best catalyst for photocatalytic solar H2 production.

Conclusion: The presence of small amounts of cobalt oxide leads to an efficient composite with TiO2 facilitating the space charge separation and increasing the lifetime of the generated photoholes and electrons. The wide versatility of TiO2-CoOx catalysts both for photooxidation and photoreduction reactions motivates to further exploit the use of these systems in real solar-driven photocatalysis. Read now: https://bit.ly/3dGdsJ5

EDITOR’S CHOICE – Mechanical and Viscoelastic Properties of In-situ Amine Functionalized Multiple Layer Graphene /epoxy Nanocomposites – Current Nanoscience

Journal: Current Nanoscience

Author(s): Pradeep Kumar Singh*, Kamal Sharma*

Graphical Abstract:

 

Abstract:

Introduction: Graphene is flat monolayer of carbon atoms (one atom thick), covalently bonded to three other atoms in tightly packed two-dimensional (2D) hexagonal single layer stable crystalline honeycomb lattice structure. In this paper, In-situ amine functionalized exfoliated graphene with multiple layers (3-6) with low defect contents and average aspect ratio upto 10 microns (average X and Y dimensions) and thickness upto 2-3 nm (average Z-direction) which have been produced with the combined effort of chemical vapor deposition (CVD) and chemical graphite exfoliation method.

Methods: This paper also focuses on the effect of the reinforcement of amine functionalized multiple graphene layers (AF-MGL) on the mechanical and visco-elastic properties of epoxy composites. AFMGL/ epoxy composites (AF-MGL/EpC) were prepared with graphene fractions ranging from 0.5 to 2.0 wt%. The four different samples were prepared using an amount of graphene as 0.0, 0.5, 1.5, and 2.0. A series of tensile three point bend tests were performed on the different AFMGL/epoxy composites. Optical and scanning electron microscopy (SEM) was used to examine the micro structural features and fractured surfaces of AF-MGL/EpC.

Results: Increased graphene content results in improved tensile strength and the modulus of an epoxy matrix when compared with the pure epoxy matrix. The 1.5 wt% AF-MGL/EpC showed an increase in tensile strength and modulus by 50.2 and 52.8% respectively. However, a shrink was noticed beyond 1.5 wt.% samples of AF-MGL/EpC composite. Moreover, an improvement of 28.8% in the storage modulus was also recorded when compared with epoxy composites.

Conclusion: The effect of the amine functional group on the mechanical and viscoelastic properties was also explored using molecular dynamics (MD) simulations and predicted results were then compared with experimental results.

Read more here: http://www.eurekaselect.com/158477/article

 

Press Release for EurekAlert! Non-ambient conditions in the investigation and manufacturing of drug forms

To become a drug, a pharmacologically active compound must be prepared in a specific form. This form must be robust during manufacturing, packaging, storage and transport, and must administer the correct dose to the patient. To successfully prepare a drug form, one often needs to produce solid samples with controlled crystal structure and a specific particle size and shape. To further complicate matters, these compounds, these drug particles must often end up as a part of a multi-component composite. The present review summarizes how extreme pressure and temperature conditions help achieve this highly tuned material.

In modern culture, it is very rare to find an individual who has never taken any form of medication. It must follow that the pharmaceutical industry is required to produce an enormous quantity of drug products, which can take a variety of different forms: solutions for injections, inhalation powders, sprays, tablets, ointments, patches, amongst others. In many cases, although adopting different administration routes, different trade names are used to market the very same active pharmaceutical ingredient (API). This begs the question: if these products are the same API, is there any difference in which form is taken?

Quite simply put, yes.

Drug molecules move around the body and, by necessity, act at the molecular level. However, many of these compounds are manufactured as solids, which must either be dissolved prior to injection, or are expected to dissolve on digestion in biological fluids. In either case, dissolution is required to release individual molecules into the body.

Solid pharmaceuticals containing the same API (either pure or with additives) can have different crystal structures (polymorphism) or be amorphous. Additionally, solid particles can differ in size, shape, meso-structure, and surface charge. Within the bulk material, the spatial distribution of an API and the additives can vary. Control of these, and many other, characteristics is within the scope of materials sciences and solid-state chemistry. The chemical and material properties of their physical form therefore needs to be identified and optimized for in vivo performance, reliable manufacture and the protection of intellectual property.

Drugs are materials, not simply molecules [1-12], By viewing drugs in this way, one can apply the knowledge of solid-state chemistry, materials science and non-ambient conditions to obtain solid forms with optimized properties. These conditions include, among others, different types of mechanical and ultrasonic treatment, hydrostatic compression, high-temperature or cryogenic spray-drying, and crystallization from supercritical solvents. Solid-state reactions (e.g. dehydration or clathrate decomposition) can be efficient in accessing metastable polymorphs or in uniformly micronizing the sample. To achieve control over drug forms and the processes used for their robust manufacturing, one needs to account for both the thermodynamic and kinetic aspects of their transformations.

The review contains over 400 references and provides a comprehensive guide through the vast ocean of publications in this field. This work is based on the personal experience of the author over several decades of active research.

For more information visit: http://benthamscience.com/journals/current-pharmaceutical-design/volume/22/issue/32/page/4981/

Editor’s Choice – “An Overview on Polylactic Acid, its Cellulosic Composites and Applications”

Journal: Current Organic Synthesis

Author(s):  Naheed Saba, Mohammad Jawaid and Othman Al-Othman

Abstract:

Poly lactic acids (PLA) received greater attention among other biodegradable plastics as they exhibit higher strength, stiffness, molecular weight and biocompatibility. PLA are polymers in which the stereo chemical structures are modified by polymerizing according to different versatile and flexible applications. The increased demands for PLA resins create a promising and attractive positive impact on the global agricultural economy by being nontoxic for both human body and the environment. However, the inherent brittleness of PLA essentially hampers its wide applications frame. PLA surface modification through blending, polymerization, filler and fiber reinforcement for fabricating high end composite products perfectly overcomes its shortcomings for various purposes. Present review article is designed to be a comprehensive source of recent literature on PLA structure, synthesis, modification and its different applications. This review article also aims to cover the reported research work of PLA biocomposites and nanocomposites, including manufacturing techniques and there diverge industrial applications.

Read more here: http://benthamscience.com/journals/current-organic-synthesis/volume/14/issue/2/page/156/