Voltage‐ and Power‐Conversion Performance of Bi‐functional ZrO2 : Er3+/ Yb3+ Assisted and Co‐sensitized Dye Sensitized Solar Cells for Internet of Things Applications

Posted on 20 September 2023 by

A bifunctional ZrO₂ : Er³⁺/Yb³⁺ co-sensitized dye-sensitized solar cell shows a power conversion efficiency of 12.35 %. Six cells connected in series gave a V_OC of 4.52 V, which is sufficient to power up internet of things (IoT) devices.

Abstract

Giant power conversion efficiency is achieved by using bifunction ZrO₂ : Er³⁺/Yb³⁺assisted co-sensitised dye-sensitized solar cells. The evolution of the crystalline structure and its microstructure are examined by X-ray diffraction, scanning electron microscopy studies. The bi-functional behaviour of ZrO₂ : Er³⁺/Yb³⁺ as upconversion, light scattering is confirmed by emission and diffused reflectance studies. The bi-function ZrO₂ : Er³⁺/Yb³⁺ (pH=3) assisted photoanode is co-sensitized by use of N719 dye, squaraine SPSQ2 dye and is sandwiched with Platinum based counter electrode. The fabricated DSSC exhibited a giant power conversion efficiency of 12.35 % with V_OC of 0.71 V, J_SC of 27.06 mA/cm², FF of 0.63. The results, which motivated the development of a small DSSC module, gave 6.21 % and is used to drive a tiny electronic motor in indoor and outdoor lighting conditions. Small-area DSSCs connected in series have found that a V_OC of 4.52 V is sufficient to power up Internet of Things (IoT) devices.

Water‐Soluble Fullerene Monoderivatives for Biomedical Applications

Posted on 20 September 2023 by

Monoderivatives of fullerenes functionalized with hydrophilic groups make them water soluble, while preserving the hydrophobic fullerene cage. These molecules have intriguing biomedical applications, including drug delivery, photodynamic therapy (PDT), antiviral and antimicrobial activity and reactive oxygen species (ROS)-scavenging abilities. Herein we discuss the synthesis and biomedical applications of water-soluble fullerene monoderivatives and their biological behavior based on their structures. (Image created with BioRender.com.)

Abstract

Monoderivatives of fullerenes functionalized with hydrophilic groups make them water soluble, while preserving the hydrophobic fullerene cage. This class of molecules have intriguing biomedical applications, including drug delivery, photodynamic therapy (PDT), antiviral and antimicrobial activity and reactive oxygen species (ROS)-scavenging abilities. In this Concept we discuss the synthesis and biomedical applications of water-soluble fullerene monoderivatives and their biological behavior based on their structures.

Direct Experimental Observations of Ion Distributions during Overcharging at the Muscovite‐Water Interface by Adsorption of Rb+ and Halides (Cl−, Br−, I−) at High Salinity

Posted on 20 September 2023 by nJulia Neumann, nSang Soo Lee, nEric J. Zhao, nPaul Fentern

Classical electric double layer (EDL) models fail to describe ion distributions at charged solid-liquid interfaces at high salinity, where non-classical effects such as ion-ion correlations play a role. Here, the authors report the direct experimental determination of interfacial cation and anion distributions yielding new insights into the EDL structure and the associated adsorption isotherm data in the overcharging regime.

Abstract

Classical electric double layer (EDL) models have been widely used to describe ion distributions at charged solid-water interfaces in dilute electrolytes. However, the chemistry of EDLs remains poorly constrained at high ionic strength where ion-ion correlations control non-classical behavior such as overcharging, i. e., the accumulation of counter-ions in amounts exceeding the substrate's surface charge. Here, we provide direct experimental observations of correlated cation and anion distributions adsorbed at the muscovite (001)-aqueous electrolyte interface as a function of dissolved RbBr concentration ([RbBr]=0.01–5.8 M) using resonant anomalous X-ray reflectivity. Our results show alternating cation-anion layers in the EDL when [RbBr]≳100 mM, whose spatial extension (i. e., ~20 Å from the surface) far exceeds the dimension of the classical Stern layer. Comparison to RbCl and RbI electrolytes indicates that these behaviors are sensitive to the choice of co-ion. This new in-depth molecular-scale understanding of the EDL structure during transition from classical to non-classical regimes supports the development of realistic EDL models for technologies operating at high salinity such as water purification applications or modern electrochemical storage.

On The Nature of FeIV=Oaq in Aqueous Media: A DFT analysis

Posted on 20 September 2023 by nBasil Raju Karimadom, nDan Meyerstein, nHaya Kornweitzn

Density functional calculations demonstrate that the Fe^IV=O²⁺ _aq complexes form different analogous complexes according to the pH of the system.

Abstract

Fe^IV=O_aq is a key intermediate in many advanced oxidation processes and probably in biological systems. It is usually referred to as Fe^IV=O²⁺. The pKa's of Fe^IV=O_aq as derived by DFT are: pKa1=2.37 M06 L/6-311++G(d,p) (SDD for Fe) and pKa2=7.79 M06 L/6-311++G(d,p) (SDD for Fe). This means that in neutral solutions, Fe^IV=O_aq is a mixture of (H₂O)₄(OH)Fe^IV=O⁺ and (H₂O)₂(OH)₂Fe^IV=O. The oxidation potential of Fe^IV=O_aq in an acidic solution, E⁰{(H₂O)₅Fe^IV=O²⁺/Fe^III(H₂O)₆ ³⁺, pH 0.0} is calculated with and without a second solvation sphere and the recommended value is between 2.86 V (B3LYP/Def2-TZVP, with a second solvation sphere) and 2.23 V (M06 L/Def2-TZVP without a second solvation sphere). This means that Fe^IV=O_aq is the strongest oxidizing agent formed in systems involving Fe^VIO₄ ²⁻ even in neutral media.

Access to High‐Purity 7mG‐cap RNA in Substantial Quantities by a Convenient All‐Chemical Solid‐Phase Method

Posted on 20 September 2023 by

A practical and valuable all-chemical method has been developed to synthesize 5’-^7mGppp RNA on solid-support without damaging the ^7mG-cap or the RNA during RNA deprotection and release from the support under mild basic conditions. Substantial quantities of high-purity 5’-^7mGppp RNA are thus affordable as useful research tools.

Abstract

Given the importance of mRNA with 5’-cap, easy access to RNA substrates with different ^7mG caps, of high quality and in large quantities is essential to elucidate the roles of RNA and the regulation of underlying processes. In addition to existing synthetic routes to 5’-cap RNA based on enzymatic, chemical or chemo-enzymatic methods, we present here an all-chemical method for synthetic RNA capping. The novelty of this study lies in the fact that the capping reaction is performed on solid-support after automated RNA assembly using commercial 2’-O-propionyloxymethyl ribonucleoside phosphoramidites, which enable final RNA deprotection under mild conditions while preserving both ^7mG-cap and RNA integrity. The capping reaction is efficiently carried out between a 5’-phosphoroimidazolide RNA anchored on the support and ^7mGDP in DMF in the presence of zinc chloride. Substantial amounts of ^7mG-cap RNA (from 1 to 28 nucleotides in length and of any sequence with or without internal methylations) containing various cap structures (^7mGpppA, ^7mGpppA_m, ^7mGppp^m6A, ^7mGppp^m6A_m, ^7mGpppG, ^7mGpppG_m) were obtained with high purity after IEX-HPLC purification. This capping method using solid-phase chemistry is convenient to perform and provides access to valuable RNA substrates as useful research tools to unravel specific issues regarding cap-related processes.

Terpenoids as Human Neutrophil Elastase (HNE) Inhibitors: A Comprehensive Review of Natural Anti‐inflammatory Isoprenoids

Posted on 20 September 2023 by

The information on the potential therapeutic effects of terpenoids reviewed here should help to guide researchers in the development of safer and more effective drugs derived from natural terpenoid compounds for managing inflammatory problems.

Abstract

Human neutrophil elastase (HNE) is an enzyme that plays a key role in the body‘s inflammatory response. It has been linked to several diseases such as chronic obstructive pulmonary disease (COPD), emphysema, and cystic fibrosis. As potential treatments for these diseases, HNE inhibitors are of great interest. Metabolites derived from plants, particularly terpenoids such as β-caryophyllene found in black pepper and other plants, and geraniol present in several essential oils, are recognized as significant sources of inhibitors for HNE. Because of their ability to inhibit HNE, terpenoids are considered promising candidates for developing novel therapies to treat inflammatory conditions such as COPD and emphysema. Furthermore, nature can serve as an excellent designer, and it may offer a safer drug candidate for inhibiting HNE production and activity in the future. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses were searched to get relevant and up-to-date literature on terpenoids as human neutrophil elastase inhibitors. This review focuses on the isolation, chemical diversity, and inhibition of human neutrophil elastase (HNE) of various terpenoids reported from natural sources up to 2022. A total of 251 compounds from various terpenoids classes have been reported. Further, it also provides a summary of HNE inhibitors and includes a thorough discussion on the structure-activity relationship.

Strong Metal‐support Interactions in Photocatalysis: Fundamentals and Design Methods

Posted on 20 September 2023 by nVien‐Duong Quach, nRobert Wojcieszak, nMohamed Nawfal Ghazzaln

This review focuses on recent efforts to enhance photocatalytic activities of metal nanoparticle-mediated photocatalysts through “strong metal-support interaction” (SMSI). Herein, we discuss the fundamentals of “strong metal-support interaction” and the methodology to practice the concept, involving synthesis and characterization techniques. The strengths and limitations of SMSI are also discussed, thus outlining future perspectives.

Abstract

Engineering the composition and geometry of metallic sites has become a popular manner to boost reaction rate and control reaction selectivity in heterogeneous catalysis. Many studies have been devoted to enhancing the stability of metallic nanoparticles during catalytic reactions by dispersion on metal oxide supports such as TiO₂, CeO₂ or Nb₂O₅. These supports not only modulate electronic properties and dispersion/stabilization of metallic nanoparticle but also influence catalytic selectivity, resulting in the so-called “strong metal-support interaction” (SMSI). In this minireview, we outlined the discovery and fundamentals of SMSI, as well as its extensive development over years. In addition, we summarized recent approaches developed to induce the construction of SMSI between different metal nanoparticles and metal oxide supports. Associated characterization microscopic and spectroscopic techniques were emphasized. Despite being a prevalent concept in catalysis, the number of studies on SMSI in heterogeneous photocatalysis has been even in limitation. Herein, we highlighted the beneficial effects of SMSI on boosting photocatalytic activity for CO₂ reduction and H₂ evolution reactions. In general, despite some controversial aspects of the SMSI, this concept offers wide opportunities ahead and encourages researchers to rethink the local active site localization and photocatalyst design.

Stability of Bipolar Plate Materials for Proton‐Exchange Membrane Water Electrolyzers: Dissolution of Titanium and Stainless Steel in DI Water and Highly Diluted Acid

Posted on 20 September 2023 by

We studied the stability of bipolar plate materials on-line. To mimic application-near conditions, we measured in deionized water and 0.5 mM H₂SO₄. For titanium, the dissolution is negligible, whereas for stainless steel 316L notable dissolution is detected. Yet, it remained below the reported poisoning limit for Nafion-based proton exchange membranes.

Abstract

The widespread use of proton exchange membrane water electrolyzers (PEMWE) is hindered by their high cost, of which a colossal factor is caused by the bipolar plates (BPP). In this paper, we investigate the stability of two BPP materials on-line with an optimized scanning flow cell setup coupled to an inductively coupled plasma mass spectrometer (SFC-ICP-MS), as well as scanning electron microscopy (SEM). The stability of currently used titanium and a cheaper alternative, stainless steel (SS) 316L, were characterized in deionized (DI) water and 0.5 mM H₂SO₄ to mimic the conditions at the BPP under operation. We show that the dissolution of Ti is negligible, whereas SS 316L degrades notably. Here, besides pH, the applied potentials play a crucial role. Nonetheless, even for the highest measured dissolution rate of SS 316L, the contamination in a full cell is estimated to remain below 1 ppm. This work illustrates the capabilities of on-line high-throughput stability tests for BPP materials and could therefore contribute towards optimization of cost-effective PEMWE.

Excellent MCM‐49 Supported CeCuOx Nanocatalyst with Ultrawide Operating Temperature Window and Strong Anti‐Alkali Ability for NH3‐SCR

Posted on 20 September 2023 by

Schematic diagram of the dominant mechanism of NH₃-SCR reaction on CeCu/MCM-49 catalyst before and after poisoning. The L−H mechanism was dominant before poisoning. However, after alkali metal poisoning, NO_x adsorption on the catalyst is inhibited, so the E−R mechanism dominates.

Abstract

NO_x is a common atmospheric pollutant, and NH₃-SCR technology efficiently purifies it. CeCuO_x binary-oxide nanoparticles were synthesized and loaded onto acid MCM-49 molecular sieve with a large specific surface area to increase acid sites and disperse active sites of the catalyst. The optimized 35 % CeCu/MCM-49 catalyst effectively purified over 80 % of NO_x in the temperature range of 200–500 °C and demonstrated excellent resistance to alkali metals, such as K, Na, and Ca. Even after K poisoning, it still removed over 80 % of NO_x in the range of 200–450 °C. Various characterization methods, including XRD, FT-IR, TEM, and N₂ isotherm adsorption-desorption tests, confirmed the structure of the catalyst remained intact after poisoning with no substance change, nor agglomeration of nanoparticles. NH₃-TPD and H₂-TPR confirmed that the catalyst had effective acidity and redox capacity that were not affected by alkali metals. In-situ DRIFTs showed that the catalytic reaction predominant mechanism shifted from L−H to E−R mechanism after poisoning. This study provides valuable insights into the development of high-performance Ce-based NH₃-SCR catalysts with alkali metal resistance.

A strategy for improving the efficiency of boronic acid catalysis in the synthesis of amides.

Posted on 20 September 2023 by nFatima Almetwali, nJacques Rouden, nJérôme Blanchetn

This study outlines the development of novel boronic acids as catalysts for the direct synthesis of amides from carboxylic acids and amines. The Lewis acidity of the boronic acids was estimated by means of computational techniques, and the observed increase in catalytic activity was corroborated by kinetic data derived from a model reaction. Our investigations led to the discovery of a set of ortho-(sulfonyloxy)benzeneboronic acids that compared favorably with the established state-of-the-art. These newly developed catalysts demonstrated efficacy in the coupling of aliphatic, aromatic, and heteroaromatic acids, as well as primary and secondary amines.