Graphene in Photocatalysis: A Review Li, Xin; Yu, Jiaguo; Wageh, S. ...
Small (Weinheim an der Bergstrasse, Germany)
12, Issue:
48
Journal Article
Peer reviewed
In recent years, heterogeneous photocatalysis has received much research interest because of its powerful potential applications in tackling many important energy and environmental challenges at a ...global level in an economically sustainable manner. Due to their unique optical, electrical, and physicochemical properties, various 2D graphene nanosheets‐supported semiconductor composite photocatalysts have been widely constructed and applied in different photocatalytic fields. In this review, fundamental mechanisms of heterogeneous photocatalysis, including thermodynamic and kinetics requirements, are first systematically summarized. Then, the photocatalysis‐related properties of graphene and its derivatives, and design rules and synthesis methods of graphene‐based composites are highlighted. Importantly, different design strategies, including doping and sensitization of semiconductors by graphene, improving electrical conductivity of graphene, increasing eloectrocatalytic active sites on graphene, strengthening interface coupling between semiconductors and graphene, fabricating micro/nano architectures, constructing multi‐junction nanocomposites, enhancing photostability of semiconductors, and utilizing the synergistic effect of various modification strategies, are thoroughly summarized. The important applications including photocatalytic pollutant degradation, H2 production, and CO2 reduction are also addressed. Through reviewing the significant advances on this topic, it may provide new opportunities for designing highly efficient 2D graphene‐based photocatalysts for various applications in photocatalysis and other fields, such as solar cells, thermal catalysis, separation, and purification.
Fundamental mechanisms of heterogeneous photocatalysis, including thermodynamic and kinetics requirements, are first systematically summarized. Then, the photocatalysis‐related properties of graphene and its derivatives, and design rules and synthesis methods of graphene‐based composites are highlighted. The important applications including photocatalytic pollutant degradation, H2 production, and CO2 reduction are also addressed.
Contamination by chemicals from the environment is a major global food safety issue, posing a serious threat to human health. These chemicals belong to many groups, including metals/metalloids, ...polycyclic aromatic hydrocarbons (PAHs), persistent organic pollutants (POPs), perfluorinated compounds (PFCs), pharmaceutical and personal care products (PPCPs), radioactive elements, electronic waste, plastics, and nanoparticles. Some of these occur naturally in the environment, whilst others are produced from anthropogenic sources. They may contaminate our food—crops, livestock, and seafood—and drinking water and exert adverse effects on our health. It is important to perform assessments of the associated potential risks. Monitoring contamination levels, enactment of control measures including remediation, and consideration of sociopolitical implications are vital to provide safer food globally.
CdSe nanocrystallites capped with mercaptoacetic acid with a high intensity band edge emission were synthesized, and double layered hybrid light emitting devices with various structures were ...fabricated. The double layers are a blend of polyvinyl carbazole (PVK) mixed with CdSe nanoparticles and Alq 3 layer, which are encapsulated between ITO as anode and LiF/Al as cathode. Different devices were fabricated by varying the CdSe concentration as well as thickness of Alq 3 layer. The device that fabricated without incorporation of nanoparticles revealed an emission nearly at 510 nm, which is related to Alq 3 layer with diffusion of Li ions during the deposition of Al electrode. Increasing CdSe nanoparticles concentration and decreasing Alq 3 layer thickness leads to a decrease in the intensity of emission originated from CdSe nanoparticles. Mixing PVK with CdSe nanoparticles that produce emission mainly arises from trapping states, causing the shifting of emission zone to Alq 3 layer. Interestingly, the device shows that the most favorable emission is the one that consists of relatively as low concentration as 20% of CdSe nanoparticles of the blend layer and has a thickness of Alq 3 layer of 18 nm.
In the present review, we focused on the fundamental concepts of hydrogels—classification, the polymers involved, synthesis methods, types of hydrogels, properties, and applications of the hydrogel. ...Hydrogels can be synthesized from natural polymers, synthetic polymers, polymerizable synthetic monomers, and a combination of natural and synthetic polymers. Synthesis of hydrogels involves physical, chemical, and hybrid bonding. The bonding is formed via different routes, such as solution casting, solution mixing, bulk polymerization, free radical mechanism, radiation method, and interpenetrating network formation. The synthesized hydrogels have significant properties, such as mechanical strength, biocompatibility, biodegradability, swellability, and stimuli sensitivity. These properties are substantial for electrochemical and biomedical applications. Furthermore, this review emphasizes flexible and self-healable hydrogels as electrolytes for energy storage and energy conversion applications. Insufficient adhesiveness (less interfacial interaction) between electrodes and electrolytes and mechanical strength pose serious challenges, such as delamination of the supercapacitors, batteries, and solar cells. Owing to smart and aqueous hydrogels, robust mechanical strength, adhesiveness, stretchability, strain sensitivity, and self-healability are the critical factors that can identify the reliability and robustness of the energy storage and conversion devices. These devices are highly efficient and convenient for smart, light-weight, foldable electronics and modern pollution-free transportation in the current decade.
The nanocomposite composed of Nickel-cobalt layered double hydroxide and reduced graphene oxide (NiCo-LDH/rGO) has been successfully synthesized by solvothermal treatment of ZIF-67/GO, exhibiting ...high specific capacitance and excellent rate capability.
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Supercapacitors are deemed as reliable power sources for portable devices and electric vehicles. Electrode materials with high energy and power densities are greatly needed. Herein, we designed reduced-graphene-oxide supported nickel-cobalt layered double hydroxide nanosheets (NiCo-LDH/rGO) as electrode materials. The introduction of graphene could largely enhance the conductivity, and the supported NiCo-LDH could effectively prevent graphene from self-aggregation. Thanks to the synergistic effect of conductive graphene and electro-active LDH, the nanocomposites delivered a capacitance of 1675 F g−1 at 1 A g−1 and decent rate performance (capacitance retention of 83.8% at 10 A g−1); while NiCo-LDH could only exhibited a capacitance of 920 F g−1 at 1 A g−1 and 81.5% of the capacitance remained at 10 A g−1. The asymmetric supercapacitors assembled with NiCo-LDH/rGO and activated carbon (AC) delivered high energy density and power density, up to 49.9 Wh kg−1 and 3747.9 W kg−1, respectively. The appealing electrochemical performance indicates its huge application potential in supercapacitors.
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Wastewater containing organic dyestuff has caused worldwide concern, hence, it is imperative to develop materials to remove organic dyes from wastewater. Herein, we report the ...synthesis of carbon fiber-based bimetallic oxide nanocomposite with high efficiency for the adsorptive removal of Congo red (CR), a typical anionic dye. Composite nanosheets of nickel(II) oxide (NiO) and zinc oxide (ZnO) were in situ grown over electrospun carbon fibers via one-step oil bath coprecipitation and subsequent calcination in air at 350 °C. The C/NiO-ZnO nanocomposite fibers exhibited fast adsorption rates towards CR at circumneutral pH, and maximal adsorption capacity according to the Langmuir model reached 613 mg g−1, much higher than aggregated NiO-ZnO microspheres and the carbon fiber alone. The high adsorption capacity of the C/NiO-ZnO nanocomposite was attributed to its high specific surface area (222 m2 g−1), hierarchically porous structure with abundant mesopores and macropores, and the positive surface charge at circumneutral pH. Therefore, the flexible and easily recyclable C/NiO-ZnO nanocomposite fibers can become an alternative adsorbent for the treatment of anionic dye wastewater.
Plasmalogens derived from dietary phospholipids are considered to be potential protectors against oxidation-related disorders, while lead (Pb) is an environmental contaminant worldwide and is known ...to induce oxidative stress. However, the protective and antilipid oxidative effects of individual plasmalogen species against Pb damage have received little attention. In this study, six plasmalogen species (with either choline or ethanolamine as the headgroup and p16:0/18:1, p16:0/18:2, or p16:0/20:5 as the side chains) were evaluated in human hepatoma cells. Plasmalogen species showed a remarkable recovery in cell viability as well as elimination of reactive oxygen species and suppressed the accumulation of phosphatidylcholine hydroperoxides (from 63.6 ± 1.8% to 80.3 ± 2.9%) and phosphatidylethanolamine hydroperoxides (from 25.7 ± 9.3% to 76.1 ± 3.7%). Moreover, plasmalogens significantly upregulated the gene expression levels of a series of antioxidant enzymes that are regulated via the Nrf-2-dependent pathway. This study suggested that choline and ethanolamine plasmalogens could prevent Pb-induced cytotoxicity and lipid oxidation in HepG2 cells.
The research is aimed at introducing the low temperature and extremely simple method of preparing ZnS:Te, within aqueous media. In order to accomplish this research objective, the research is ...intended to perform analysis of the prepared nanoparticles by using different techniques. Some of the major techniques include X-ray diffraction, optical transmission, photoluminescence (PL), and infrared and Raman spectroscopies. In this research, ZnS
(1−x)
Te
(x)
, with x = 0.0, 0.05 and 0.2 nanoparticles, was synthesized, for the first time, in aqueous medium by colloidal method. The synthesized nanoparticles were characterized by using XRD, EDX, and UV–Vis optical transmission, PL, thermogravimetric, and FTIR and Raman spectroscopies. XRD analysis confirmed that the prepared nanoparticles had zinc blende structure and that the size of nanoparticles ranged from 1.8 to 2.5 nm. Optical transmission revealed energy gap of 4.05–3.36 eV and high transmission in the infrared region of the prepared nanoparticles, doped with Te. PL and PL excitation showed formation of isoelectronic trapping states in forbidden gap for the doped nanoparticles.
Glioma is often referred to as one of the most dreadful central nervous system (CNS)-specific tumors with rapidly-proliferating cancerous glial cells, accounting for nearly half of the brain tumors ...at an annual incidence rate of 30-80 per a million population. Although glioma treatment remains a significant challenge for researchers and clinicians, the rapid development of nanomedicine provides tremendous opportunities for long-term glioma therapy. However, several obstacles impede the development of novel therapeutics, such as the very tight blood-brain barrier (BBB), undesirable hypoxia, and complex tumor microenvironment (TME). Several efforts have been dedicated to exploring various nanoformulations for improving BBB permeation and precise tumor ablation to address these challenges. Initially, this article briefly introduces glioma classification and various pathogenic factors. Further, currently available therapeutic approaches are illustrated in detail, including traditional chemotherapy, radiotherapy, and surgical practices. Then, different innovative treatment strategies, such as tumor-treating fields, gene therapy, immunotherapy, and phototherapy, are emphasized. In conclusion, we summarize the article with interesting perspectives, providing suggestions for future glioma diagnosis and therapy improvement.
Glioma originates from the aberrant proliferation of brain glial cells, accounting for the highest mortality among major CNS malignancies. Apart from traditional surgical ablation, there still lacks effective long-term therapy. In the present review, glioma pathogenesis and conventional treatments are firstly illustrated. Recent advancements in glioma diagnosis and therapeutics based on nanomaterials are then categorized and discussed with suggestions for future improvement. Display omitted
Cadmium-based alloyed quantum dots are one of the most popular metal chalcogenides in both the industrial and research fields owing to their extraordinary optical and electronic properties that can ...be manipulated by varying the compositional ratio in addition to size control. This report aims to cover the main information concerning the synthesis techniques, properties, and applications of Cd-based alloyed quantum dots. It provides a comprehensive overview of the most common synthesis methods for these QDs, which include hot injection, co-precipitation, successive ionic layer adsorption and reaction, hydrothermal, and microwave-assisted synthesis methods. This detailed literature highlights the optical and structural properties of both ternary and quaternary quantum dots. Also, this review provides the high-potential applications of various alloyed quantum dots.
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