SAINSTEK International Journal on Applied Science, Advanced Technology and Informatics

Advancements in Metal Oxide Redox Cycles for Solar-Driven Chemical Processes: Oxygen Separation, Fuel Synthesis, Ammonia Generation, and Thermochemical Energy Storage

2024-12-23T03:12:20+00:00

This review paper presents an in-depth exploration of metal oxide redox cycles applied to solar chemical processing, encompassing thermochemical oxygen separation, fuel production (H2, CO), ammonia synthesis, and thermochemical energy storage. The focus is on solar-driven thermochemical H2O and CO2 splitting cycles, utilizing monolithic solar reactors with a porous reactive structure for efficient two-step redox reactions. Isothermal plots highlight the relationship between δ and pO2 in CeO2/CeO2−δ systems with temperature and pressure variations. The study showcases hierarchically ordered porous structures achieved through additive manufacturing, enhancing solar radiation absorption. Customized ceria materials, demonstrated in packed-bed cavity-type solar reactors, exhibit notable O2, CO, and H2 production rates during consecutive thermochemical splitting cycles. The review further discusses the synthesis of La/Sr/Mn perovskites via solution combustion, presenting CO production yield patterns. Ammonia synthesis reactions are assessed through Gibbs free energy variation with temperature, while AlN hydrolysis extent is evaluated at different H2O concentrations. Additionally, the concept of thermochemical energy storage is outlined, elucidating its potential in supplying high-temperature process heat for electricity or fuel generation. This comprehensive review contributes to the understanding and advancement of solar-driven chemical processes and their pivotal role in sustainable energy technologies.

Insights into Crystallization Mechanisms Enabling Manganese Oxide Polymorph Formation: A Comprehensive Review

2024-12-23T03:19:53+00:00

In this comprehensive review, we delve into the intricate pathways underlying the formation of manganese oxide polymorphs, shedding light on their crystallization mechanisms. Manganese oxides, exhibiting diverse structures and properties, play pivotal roles in various fields, from energy storage to catalysis. We explore the dynamic interplay between synthesis conditions, precursor materials, and reaction kinetics that govern polymorph evolution. Through an in-depth analysis of experimental findings and theoretical insights, we elucidate the factors dictating the transformation of precursor species into distinct polymorphic phases. Additionally, we discuss the influence of external parameters such as temperature, pH, and reactant concentrations on the polymorph selection process. This review also addresses the implications of polymorphism in tailoring material functionalities and properties. By amalgamating data from various studies, we propose a unified framework for understanding the nucleation and growth mechanisms that drive polymorph formation. Our synthesis of the current state of knowledge not only contributes to advancing the fundamental understanding of manganese oxide crystallization but also guides the rational design of novel materials with tailored properties. Ultimately, this review serves as a valuable resource for researchers, offering comprehensive insights into the fascinating realm of manganese oxide polymorphism.

Advances in Electrode Design for Enhanced Electrochemical Gas Reduction Reactions: Challenges, Concepts, and Practical Solutions

2024-12-24T03:52:40+00:00

This review paper delves into the imperative role of electrode design in advancing electrochemical gas reduction reactions for sustainable high-value chemical production. The study addresses current challenges in electrode design, introduces the concept of an ideal electrode to tackle these issues, and presents pragmatic strategies for constructing such electrodes based on recent research. The investigation includes the utilization of a three-electrode system comprising WO3 films as the working electrode, Ag/AgCl as the reference electrode, and Pt sheet as the counter electrode immersed in a 1 M PEG:LiI electrolyte. The coloration voltages' impact on WO3 film switching characteristics is scrutinized via the Chronoamperometry (CA) technique. Additionally, the electrochemical exfoliation of graphite into graphene nanosheets is detailed, highlighting the process's observations and outcomes. The research further evaluates six carbon materials as bromine electrodes through a three-electrode half-cell setup, involving pristine and thermally treated conditions. These materials are explored for potential application in energy storage systems, such as lithium-ion batteries and supercapacitors. This paper contributes to the field's understanding by providing insights into electrode material selection, modification methods, and the utilization of computational modeling for performance enhancement.

Advancements in Plasma-Enhanced Chemical Vapor Deposition of Multi-Walled Carbon Nanotubes on Si/SiO2 Substrates: A Comprehensive Review

2024-12-24T03:58:16+00:00

This review paper provides an in-depth exploration of the advancements in the field of plasma-enhanced chemical vapor deposition (PECVD) for the deposition of multi-walled carbon nanotubes (MWCNTs) on Si/SiO2 substrates. The study investigates the growth process of MWCNTs utilizing iron catalytic nanoparticles generated from the decomposition of Fe(CO)5. The deposition of iron oxide nanoparticles is accomplished through a microwave plasma torch with a dual-flow nozzle electrode, as previously described in the literature. The Si/SiO2 substrate is placed in a holder accommodating multiple samples, each with a deposition area of 4 × 4 mm. Argon serves as the carrier gas, with controlled flow rates through the central and outer channels. The deposition process is conducted for 15 seconds at a plasma power of 210 W. The resulting MWCNTs' structural characteristics, such as density, alignment, and uniformity, are examined. This comprehensive review highlights the intricate interplay of process parameters and their influence on MWCNT growth. The insights provided contribute to a better understanding of PECVD-based MWCNT synthesis and pave the way for optimizing these processes for various applications, including electronic and energy devices.

Recent Advances in Electrochemical Methods for Water Treatment, Energy Conversion, and Contaminant Separation: A Comprehensive Review

2024-12-24T04:08:18+00:00

This comprehensive review paper explores recent advancements in the fields of electrochemical water treatment, energy conversion, and contaminant separation. The paper delves into the use of cyclic voltammetry (CV) curves and galvanostatic charge-discharge (GCD) curves for characterizing the performance of supercapacitors and batteries. Additionally, the review highlights a representative municipal water treatment facility's process diagram that integrates conventional purification methods to enhance water quality for domestic use. Electrochemical methods for water purification, ion separations, and energy conversion are discussed in detail. The paper also presents estimates of volumetric energy consumption in reverse osmosis (RO) and generic electrochemical processes, comparing these values to the thermodynamic limit. The intricate mechanisms of electrokinetics and electrosorption in nondestructive electrochemical contaminant separation processes are elucidated. Furthermore, the review covers water splitting for green energy generation, encompassing electrode materials and system-level considerations. It also discusses alkaline electrolyzers, catalyst film formation, and the impact of trace metal impurities. Innovative designs such as zero-gap cells and integrated electrolyzers are explained. Lastly, the paper explores an integrated flow-electrode capacitive deionization and microfiltration system for energy-efficient brackish water desalination. The review concludes by comparing the energetics of thermal amine regeneration processes with an emerging electrochemical amine regeneration (EMAR) process for carbon capture applications.