Polynuclear Cobalt Complexes as Catalysts for Light-Driven Water Oxidation: A Review of Recent Advances

Photochemical water oxidation, as a half-reaction of water splitting, represents a great challenge towards the construction of artificial photosynthetic systems. Complexes of first-row transition metals have attracted great attention in the last decade due to their pronounced catalytic efficiency in water oxidation, comparable to that exhibited by classical platinum-group metal complexes. Cobalt, being an abundant and relatively cheap metal, has rich coordination chemistry allowing construction of a wide range of polynuclear architectures for the catalytic purposes. This review covers recent advances in application of cobalt complexes as (pre)catalysts for water oxidation in the model catalytic system comprising [Ru(bpy)3]2+ as a photosensitizer and S2O82− as a sacrificial electron acceptor. The catalytic parameters are summarized and discussed in view of the structures of the catalysts. Special attention is paid to the degradation of molecular catalysts under catalytic conditions and the experimental methods and techniques used to control their degradation as well as the leaching of cobalt ions.

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Artificial photosynthesis: a molecular approach to photo-induced water oxidation

Pure and Applied Chemistry ◽

10.1515/pac-2014-1106 ◽

2015 ◽

Vol 87 (6) ◽

pp. 583-599 ◽

Cited By ~ 2

Author(s):

Giuseppina La Ganga ◽

Fausto Puntoriero

Keyword(s):

Water Oxidation ◽

Artificial Photosynthesis ◽

Organic Ligands ◽

Molecular Approach ◽

Efficient System ◽

Photosynthetic System ◽

Different Types ◽

Artificial Photosynthetic ◽

Polypyridine Complexes ◽

Molecular Catalysts

Abstract By the use of a molecular approach we performed photo-induced water oxidation by combining different photosensitizers and catalysts in order to obtain an efficient system that pave the way to the construction of an artificial photosynthetic system. Different types of molecular catalysts, such as ruthenium and vanadium polyoxometalates or cobalt core stabilized by different organic ligands were combined with ruthenium (II) polypyridine complexes of different nuclearity, mononuclear species like [Ru(bpy)3]2+ or a tetranuclear dendrimer.

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p-Sulfonic acid calix[n]arene catalyzed synthesis of bioactive heterocycles: A review

Current Organic Chemistry ◽

10.2174/1385272824999201019162655 ◽

2020 ◽

Vol 24 ◽

Author(s):

Bubun Banerjee ◽

Gurpreet Kaur ◽

Navdeep Kaur

Keyword(s):

Supramolecular Chemistry ◽

Sulfonic Acid ◽

Catalytic Efficiency ◽

The Other ◽

Reaction Conditions ◽

Metal Free ◽

Bioactive Scaffolds ◽

Wide Range ◽

Efficient Alternative ◽

Bioactive Heterocycles

: Metal-free organocatalysts are becoming an important tool for the sustainable developments of various bioactive heterocycles. On the other hand, during last two decades, calix[n]arenes have been gaining considerable attention due to their wide range of applicability in the field of supramolecular chemistry. Recently, sulfonic acid functionalized calix[n] arenes are being employed as an efficient alternative catalyst for the synthesis of various bioactive scaffolds. In this review we have summarized the catalytic efficiency of p-sulfonic acid calix[n]arenes for the synthesis of diverse biologically promising scaffolds under various reaction conditions. There is no such review available in the literature showing the catalytic applicability of p-sulfonic acid calix[n]arenes. Therefore, we strongly believe that this review will surely attract those researchers who are interested about this fascinating organocatalyst.

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Recent Advances in Enzymatic and Non-Enzymatic Electrochemical Glucose Sensing

Sensors ◽

10.3390/s21144672 ◽

2021 ◽

Vol 21 (14) ◽

pp. 4672

Author(s):

Mohamed H. Hassan ◽

Cian Vyas ◽

Bruce Grieve ◽

Paulo Bartolo

Keyword(s):

Noble Metals ◽

Direct Electrochemistry ◽

Glucose Sensing ◽

Glucose Sensors ◽

Diabetic Patients ◽

Past Century ◽

Industrial Sectors ◽

Recent Advances ◽

Wide Range ◽

Sensitivity And Selectivity

The detection of glucose is crucial in the management of diabetes and other medical conditions but also crucial in a wide range of industries such as food and beverages. The development of glucose sensors in the past century has allowed diabetic patients to effectively manage their disease and has saved lives. First-generation glucose sensors have considerable limitations in sensitivity and selectivity which has spurred the development of more advanced approaches for both the medical and industrial sectors. The wide range of application areas has resulted in a range of materials and fabrication techniques to produce novel glucose sensors that have higher sensitivity and selectivity, lower cost, and are simpler to use. A major focus has been on the development of enzymatic electrochemical sensors, typically using glucose oxidase. However, non-enzymatic approaches using direct electrochemistry of glucose on noble metals are now a viable approach in glucose biosensor design. This review discusses the mechanisms of electrochemical glucose sensing with a focus on the different generations of enzymatic-based sensors, their recent advances, and provides an overview of the next generation of non-enzymatic sensors. Advancements in manufacturing techniques and materials are key in propelling the field of glucose sensing, however, significant limitations remain which are highlighted in this review and requires addressing to obtain a more stable, sensitive, selective, cost efficient, and real-time glucose sensor.

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A bifunctional lead–iron oxyfluoride, PbFeO2F, that functions as a visible-light-responsive photoanode and an electrocatalyst for water oxidation

RSC Advances ◽

10.1039/d1ra04793k ◽

2021 ◽

Vol 11 (41) ◽

pp. 25616-25623

Author(s):

Ryusuke Mizuochi ◽

Kazunari Izumi ◽

Yoshiyuki Inaguma ◽

Kazuhiko Maeda

Keyword(s):

Visible Light ◽

Water Oxidation ◽

Wide Range ◽

Low Overpotential

The PbFeO2F serves as a bifunctional material for a water-oxidation photoanode workable under a wide range of visible light and a water-oxidation electrocatalyst operatable at a relatively low overpotential.

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Recent advances in the design of inorganic and nano-clay particles for the treatment of brain disorders

Journal of Materials Chemistry B ◽

10.1039/d0tb02957b ◽

2021 ◽

Author(s):

Francesca Persano ◽

Svetlana Batasheva ◽

Gölnur Fakhrullina ◽

Giuseppe Gigli ◽

Stefano Leporatti ◽

...

Keyword(s):

Drug Delivery ◽

Silica Nanoparticles ◽

Biomedical Applications ◽

Inorganic Materials ◽

Brain Disorders ◽

Clay Particles ◽

Recent Advances ◽

Wide Range ◽

Nano Clay

Inorganic materials, in particular nanoclays and silica nanoparticles, have attracted enormous attention due to their versatile and tuneable properties, making them ideal candidates for a wide range of biomedical applications, such as drug delivery.

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Recent Advances in the BiVO4 Photocatalyst for Sun-Driven Water Oxidation: Top-Performing Photoanodes and Scale-Up Challenges

Catalysts ◽

10.3390/catal7010013 ◽

2017 ◽

Vol 7 (12) ◽

pp. 13 ◽

Cited By ~ 122

Author(s):

Kristine Tolod ◽

Simelys Hernández ◽

Nunzio Russo

Keyword(s):

Water Oxidation ◽

Scale Up ◽

Recent Advances

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Bearing profile of sliding tribological systems

10.36652/0042-4633-2021-3-53-56 ◽

2021 ◽

pp. 53-56

Author(s):

Keyword(s):

Hydrodynamic Lubrication ◽

Surface Profile ◽

Experimental Methods ◽

Hydrodynamic Characteristics ◽

Bearing Surface ◽

Tabular Data ◽

Sliding Bearing ◽

Friction Process ◽

Operational Characteristics ◽

Wide Range

The main contours of the bearing surfaces of friction pairs with hydrodynamic lubrication are considered. Analysis of tabular data and graphs obtained by experimental methods made it possible to establish additional parameters of influence on the hydrodynamic characteristics of the friction process and the operational characteristics of tribological systems, in a wide range of load-speed modes. Keywords: sliding bearing, hydrodynamics, bushing, bearing surface, profile, circle, ellipse, wavy contour, wear. [email protected]

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Electrodeposited Thin Conformal TiO2 Coating Enabling Stable Operation of BiVO4 Photoanodes in Basic Media

ECS Meeting Abstracts ◽

10.1149/ma2018-01/31/1917 ◽

2018 ◽

Vol MA2018-01 (31) ◽

pp. 1917-1917

Author(s):

Dongho Lee ◽

Kyoung-Shin Choi

Keyword(s):

Oxygen Evolution ◽

Water Oxidation ◽

Synthesis Method ◽

Protective Layer ◽

Photoelectrochemical Cell ◽

Semiconductor Surface ◽

Stable Operation ◽

Solar Water Splitting ◽

Wide Range ◽

Basic Solutions

Producing hydrogen via solar water splitting using a photoelectrochemical cell (PEC) persists as one of the most exciting research topics in the field of solar fuels. The construction of efficient PECs requires the integration of multiple components including a photoanode, a photocathode, an oxygen evolution catalyst, and a hydrogen evolution catalyst. Therefore, the compatibility and stability of all of these elements in a given operating condition are crucial. When the stability of a semiconductor electrode used as the photoanode or photocathode is limited in an acidic or basic condition which is optimum for the operation of the other components, a thin protective layer has been deposited on the semiconductor surface to prevent its chemical dissolution. Surface coating of a thin and conformal TiO2 layer has been proven to be successful for protecting photoelectrodes since TiO2 is chemically and electrochemically stable in a wide range of pH conditions under both anodic and cathodic conditions. In order to prevent the semiconductor surface from coming into direct contact with the corrosive electrolyte, complete coverage of the photoelectrode with TiO2 is required. At the same time, the TiO2 layer should be thin enough not to interfere with the charge transport properties of the photoelectrode. As a result, atomic layer deposition (ALD) has been the only successful tool used to date to produce an effective protective layer. However, the slow processing time and economic viability of ALD methods motivated us to develop an inexpensive and facile solution-based synthesis method for the deposition of high quality TiO2 coating layers. In this presentation, we report a new electrochemical method to deposit a thin and conformal TiO2 layer on nanoporous BiVO4 that has an intricate, high surface area morphology. BiVO4 is a promising n-type photoanode material with a relatively low bandgap (2.4~2.5 eV). However, its usage has been limited to neutral and mildly basic conditions (pH 5~9) because it is chemically unstable in strongly acidic and basic conditions. Our method allows for the deposition of a 5~6 nm thick TiO2 layer on BiVO4 within 1 min and the resulting BiVO4/TiO2 electrodes exhibit chemical stability in basic solutions (pH 12~13). Sulfite oxidation measurements of BiVO4 and BiVO4/TiO2 electrodes show that the thin TiO2 protective layer does not significantly reduce the hole transfer to the electrolyte. Finally, we demonstrate the photoelectrochemical stability of the BiVO4/TiO2 electrode for photoelectrochemical water oxidation in basic solutions by coupling the BiVO4/TiO2 electrode with appropriate oxygen evolution catalysts.

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Recent Advances in Nanovaccines Using Biomimetic Immunomodulatory Materials

Pharmaceutics ◽

10.3390/pharmaceutics11100534 ◽

2019 ◽

Vol 11 (10) ◽

pp. 534 ◽

Cited By ~ 12

Author(s):

Vijayan ◽

Mohapatra ◽

Uthaman ◽

Park

Keyword(s):

Immune Responses ◽

Targeted Delivery ◽

Vaccine Development ◽

Polymeric Nanoparticles ◽

Vital Role ◽

Effective Control ◽

Therapeutic Vaccines ◽

Hiv Therapy ◽

Recent Advances ◽

Wide Range

The development of vaccines plays a vital role in the effective control of several fatal diseases. However, effective prophylactic and therapeutic vaccines have yet to be developed for completely curing deadly diseases, such as cancer, malaria, HIV, and serious microbial infections. Thus, suitable vaccine candidates need to be designed to elicit appropriate immune responses. Nanotechnology has been found to play a unique role in the design of vaccines, providing them with enhanced specificity and potency. Nano-scaled materials, such as virus-like particles, liposomes, polymeric nanoparticles (NPs), and protein NPs, have received considerable attention over the past decade as potential carriers for the delivery of vaccine antigens and adjuvants, due to their beneficial advantages, like improved antigen stability, targeted delivery, and long-time release, for which antigens/adjuvants are either encapsulated within, or decorated on, the NP surface. Flexibility in the design of nanomedicine allows for the programming of immune responses, thereby addressing the many challenges encountered in vaccine development. Biomimetic NPs have emerged as innovative natural mimicking biosystems that can be used for a wide range of biomedical applications. In this review, we discuss the recent advances in biomimetic nanovaccines, and their use in anti-bacterial therapy, anti-HIV therapy, anti-malarial therapy, anti-melittin therapy, and anti-tumor immunity.

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