Magnetic Peroxidase Nanozyme Gears Up for Microplastic Removal and Deconstruction

Posted on 12 October 2023 by nAnsari Palliyarayil, nRajani Kumar Borah, nAmit A. Vernekarn

The highlight features a recently reported approach of integrating magnetic properties of bare Fe₃O₄ nanoparticles and nanozyme technology for the removal and degradation of microplastics with nearly 100 % efficiency.

Abstract

Plastic is an important commodity that is used in several sectors. However, plastic waste generation is a pressing issue and needs attention as it risks the environment. While methods such as landfilling, incineration and recycling are known for handling plastic waste, they have their own limitations like generation of secondary pollutants and the low quality of the recycled plastic. In this scenario, new methods and technologies for efficiently handling plastic waste are the need of the hour as it is aggravating the concern of pollution and its health risks. This highlight article predominantly focuses on the recently reported combinatorial approach (Angew. Chem. Int. Ed. 2022, 61, e202212013), where it has been shown that integrating the magnetic property of bare Fe₃O₄ nanoparticles and nanozyme technology can be used for microplastic removal and degradation with nearly 100 % efficiency.

Development and Use of a Real‐time In‐situ Monitoring Tool for Electrochemical Advanced Oxidation Processes

Posted on 12 October 2023 by

The development of an apparatus for real-time in-situ monitoring of electrochemical advanced oxidation processes using visible spectrophotometry is reported. The approach uses commercially available equipment and a 3-D printable interface. It is used to monitor the anodic oxidation of Acid Orange 7, probing the impact of varying electrode composition, current density, electrolyte concentration, and stirring speed on the rate of decolorization.

Abstract

An apparatus for real-time in-situ monitoring of electrochemical advanced oxidation processes using visible spectrophotometry has been developed. Central to the design is a 3D-printed sleeve that interfaces commercially available electrochemical and spectrophotometry units. Using the anodic oxidation of Acid Orange 7 as a test bed, the apparatus has been used for probing the impact of varying electrode composition, current density, electrolyte concentration, and stirring speed on the rate of decolorization. In addition, the unit was used to prove that decolorization can continue after electrolysis has been stopped, thereby showing the inherent value of real-time monitoring. Given that a significant challenge in the field of advanced oxidation processes is the inability to compare different reported systems, our approach, using commercially available equipment and a printable interface may open avenues for more standardized data collection.

Cover Picture: (Chem. Methods 10/2023)

Posted on 12 October 2023 by Wiley: Chemistry–Methods: Table of Contents

Good Practices and Practical Considerations for Research with Perfluoroalkyl Substances

Posted on 27 September 2023 by nChloe M. Taylor, nMichael C. Breadmore, nNathan L. Kilahn

Perfluoroalkyl substances (PFAS) are a class of molecules of increasing awareness and concern. Their unique properties, hazards, and complications are not always obvious, which can impede or convolute analyses, particularly at low concentrations. We have summarised “best practice” approaches for working with PFAS with the aim of enabling chemists to do so with increased confidence and safety.

Abstract

Per- and polyfluoroalkyl substances (PFAS) are a class of hazardous pollutant that are ubiquitous in our modern world. Current research is driven by an increased awareness and concern regarding the safety of PFAS for the general population, while tightening regulations have prompted the need for detection and quantification techniques from a wide range of matrices. PFAS are a group of molecules offering unique behaviours, hazards, and complications that are not obvious or readily apparent from reading the literature. These peculiarities can impede or convolute analyses when not considered in experimental design. Drawing on the knowledge of a range of literature sources, this tutorial review looks to highlight and amalgamate the valuable suggestions and methodologies currently available to enable successful PFAS research in any laboratory.

A Review of Polymer Electrolyte Fuel Cells Fault Diagnosis: Progress and Perspectives

Posted on 5 September 2023 by nShangwei Zhou, nRhodri Jervisn

By combining detailed knowledge acquired from the established off-line characterisation of fuel cells with a careful categorisation of signatures of faults from on-line measurements, it may be possible to develop a complex and accurate understanding of the health state of electrochemical systems from more simple sensing when advanced machine learning and data-driven approaches are taken.

Abstract

Polymer electrolyte fuel cells (PEFCs) are regarded as a substitution for the combustion engine with high energy conversion efficiency and zero CO₂ emissions. Stable system operation requires control within a relatively narrow range of operating conditions to achieve the optimal output, leading to faults that can easily cause accelerated degradation when operating conditions deviate from the control targets. Performance recovery of the system can be realized through early fault diagnosis; therefore, accurate and effective diagnostic characterisation is vital for long-term serving. A review of off-line and on-line techniques applied to the fault diagnosis of fuel cells is presented in this work. Off-line approaches include electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), galvanostatic charge (GSC), visualisation-based and image-based techniques; the on-line methods can be divided into model-based, data-driven, signal-based and hybrid methods. Since each methodology has advantages and drawbacks, its effectiveness is analysed, and limitations are highlighted.

SERS Detection of Hg2+ using Rhenium Carbonyl Labelled Nanoparticle Films

Posted on 5 September 2023 by

A rhenium carbonyl complex is shown to demonstrate the ability to form a stable silver nanoparticle lustrous film, whilst having a visible response to the presence of Hg²⁺ leading to new materials for “labelled” sensing using surface enhanced Raman spectroscopy.

Abstract

Modified silver nanoparticles with a self-assembled disulfide functionalized 2,2'-bipyridine (L1 and L2) monolayer, and the corresponding rhenium complex [Re(L2)(CO)₃Br] are shown to provide a method to position the nanoparticles at a water/dichloromethane interface forming a lustrous metal-like-liquid film (MeLLF) with a unique SERS response. The film formed using L2 showed divergent behaviour in the presence of a range of metal ions whilst bound to the surface. [Re(L)(CO)₃Br] (where L=2,2'-bipyridine, L1 and L2) in solution demonstrates a selective interaction with Hg²⁺, observed by UV-vis, emission and ¹H NMR spectroscopy, attributed to abstraction of the bromide. This interaction was demonstrated by subtle changes in the characteristic Raman Re-CO stretch at 510 cm⁻¹ both with the MeLLF, and when the film is immobilized in a PVA surface-exposed-nano-sheet (SENS). The work provides proof of concept that the organometallic complexes can be employed as “labels” to generate SERS-active nanoparticle films that possess detection capabilities.

Operando Laboratory‐based X‐ray Absorption Spectroscopy: Guidelines for Newcomers in the Field

Posted on 17 August 2023 by

Operando laboratory-based X-ray absorption spectroscopy (XAS) offers new possibilities for deducing a fundamental understanding of functional materials, such as solid catalysts, without the need of a synchrotron facility. Facilitating the accessibility will speed up its establishment as a more routine analytical tool in the laboratory. The described ten steps towards a successful operando laboratory-based XAS experiment serve as guidelines for newcomers in the field and may foster the design of new or improved functional materials.

Abstract

The new possibility to perform operando X-ray absorption spectroscopy (XAS) in the laboratory expands the potential field of applications towards a broad research community. These applications are multidisciplinary at heart and benefit from joint expertise from different fields, most importantly chemistry, physics, geology, and instrumentation. Hence, a development of collaboration networks that combine skills and knowhow from different fields is highly beneficial in this endeavor. As operando laboratory-based XAS constitutes a highly interesting, advanced, and powerful characterization technique, we provide in this article practical guidelines for newcomers in the field, who would like to employ it. Here, we will describe ten important steps towards a successful operando laboratory-based XAS experiment, which are not only useful for the catalysis community, but for a much wider audience from other research fields, such as environmental chemistry as well as battery and fuel cell research.

Quantification of CO and Further CO2 Reduction Products by On‐line Mass Spectrometry

Posted on 9 August 2023 by nJonas Englhard, nJulien Bachmannn

Careful adjustment of ionization energy enables the specific quantification of carbon monoxide in gas mixtures containing CO₂ and N₂, both of which otherwise would cause interferences. This technique is applied for the analysis of CO₂RR products, both for headspace gas analysis as well as in real-time analysis, also known as differential electrochemical mass spectrometry.

Abstract

The reduction of CO₂ in water can yield a variety of volatile products mixed with the starting material and often dinitrogen as an inert gas. While mass spectrometry is ideally suited to the quantitative analysis of gases in low concentrations, the simultaneous detection is usually performed with a preliminary chromatographic separation. In its absence, the mass spectrometric signal at m/z=28 can be due to CO, CO₂, and N₂. Here, we demonstrate that ionizing the mixture of reaction products under 16 eV results in the selective detection of CO at m/z=28, at the complete exclusion of CO₂ and N₂. This method is applicable to headspace analysis after a bulk electrolysis and delivers product compositions as they depend on catalyst and applied potential. Furthermore, its immediate nature also enables the experimentalist to perform, in real time, a direct monitoring of the reaction products generated during cyclic voltammetry.

Versa DB: Assisting 13C NMR and MS/MS Joint Data Annotation Through On‐Demand Databases.

Posted on 17 July 2023 by

VersaDB is python-based program that first create a DB of natural products according to taxonomical criteria then predict MS/MS spectra and ¹³C NMR chemical shift to produce spectral DB ready for integration in dereplication workflows.

Abstract

Compound identification in complex mixtures by NMR and MS is best achieved through experimental databases (DB) mining. Experimental DB frequently show limitations regarding their completeness, availability or data quality, thus making predicted database of increasing common use. Querying large databases may lead to select unlikely structure candidates. Two approaches to dereplication are thus possible: filtering of a large DB before search or scoring of the results after a large scale search. The present work relies on the former approach. As far as we know, nmrshiftdb2 is the only open-source ¹³NMR chemical shift predictor that can be freely operated in batch mode. CFM-ID 4.0 is one of the best-performing open-source tools for ESI-MS/MS spectra prediction. LOTUS is a freely usable and comprehensive collection of secondary metabolites. Integrating the open source database and software LOTUS, CFM-ID, and nmrshiftdb2 in a dereplication workflow requires presently programming skills, owing to the diversity of data encoding and processing procedures. A graphical user interface that integrates seamlessly chemical structure collection, spectral data prediction and database building still does not exist, as far as we know. The present work proposes a stand–alone software tool that assists the identification of mixture components in a simple way.

Recent Developments in Reactor Automation for Multistep Chemical Synthesis

Posted on 22 June 2023 by nAdam D. Claytonn

Automation in multistep synthesis involves the use of robotics, advanced software, and machine learning algorithms to streamline the complex process of creating molecules. This review highlights recent advances in automated batch and continuous flow platforms, and presents how these technologies can be applied in the development and optimisation of multistep processes.

Abstract

Reactor automation is revolutionising the way new chemical processes are discovered and developed. Assigning repetitive aspects of chemical synthesis to machines, such as experimental execution and data collection, provides more time for researchers to focus on critical interpretation and creative problem solving. The ability to autonomously prepare late-stage intermediates and complex products, rather than just simple starting materials, will play a central role in applications such as the efficient exploration of chemical space and responsive manufacturing. However, translating automated technologies from specific single-step tasks to more general multistep syntheses remains a significant challenge, owing to high structural diversity and chemical/physical interdependencies between the steps. Robotic batch and continuous flow platforms are gradually becoming more universal, providing access to a wider range of chemistries required to achieve autonomous multistep synthesis. Advances in process analytical technologies have enhanced our ability to monitor interconnected reactions in real-time, thus accelerating data collection and giving greater process control for ensuring a high standard of safety and product quality. Integration of these tools with control software creates a feedback loop, which can be harnessed for adaptive and flexible multistep screening or holistic self-optimisation. This review presents recent developments in the application of automated reactor technologies for multistep chemical synthesis, including batch and continuous flow platforms. Specifically, this review highlights how the integration of control software with advanced process analytical technologies and machine learning algorithms are accelerating the synthesis of complex molecules.