Highly efficient catalytic degradation of low-density polyethylene using a novel tungstophosphoric acid/kaolin clay composite catalyst

In order to take advantage of Bronsted acidity of tungstophosphoric acid(TPA) and Lewis acidity of kaolin, TPA loaded kaolin catalysts with varying percentages of TPA (10-50wt%) have been prepared by wet impregnation method. Fourier Transform Infra-Red Spectrometer, X-ray diffractometer, Brunauer-Emmett-Teller surface area analyzer, and Scanning Electron Microscope characterizations were performed to confirm the successful loading of TPA onKaolin. Catalytic cracking of low-density polyethylene (LDPE), by employing our TPA loaded Kaolin as the catalyst, produced a higher percentage of fuel oil (liquid and gaseous hydrocarbons) with negligible amount of semisolid wax (1.0 wt.%), significantly lower compared to the thermal cracking which produced ~22wt.% solid black residue. Moreover, GCMS analysis of oil showed that thermal cracking produces mainly higher hydrocarbons(C22) as compared to the catalytic cracking where larger fraction oflowerhydrocarbons were obtained. We purpose that the higher performance of our catalysts was due to the presence of both Bronsted and Lewis acid sites, which increase their catalytic efficiency and degraded the LDPE at the relatively lower temperatures. Our results suggest that prepared materials were effectivecatalysts with low cost and easily scalable production method; suitable for large-scale highperformance catalytic cracking of LDPE based materials

In situ synthesis of copper nanoparticles on SBA-16 silica spheres

A chemical method for in situ synthesis of copper nanoparticles on SBA-16 silica spheres under ambient conditions has been reported. The silica support has been introduced into copper precursor solution before chemical reduction. Metal ions diffuse into mesopores (pore diameter 5–7 nm) of silica where in situ reduction by hydrazine leads to formation of nanoparticles. These mesopores act as nanoreactor and their walls prevent metal particle’s agglomeration by providing a physical barrier. The obtained copper nanoparticles have been investigated by electron microscopy, X-ray diffraction, UV–Visible spectroscopy, Fourier transform Infra-red spectroscopy and thermogravimetric analyzer. SEM, TEM and UV–Visible spectroscopic images revealed that nanosized particles have been successfully synthesized by this method. Thermogravimetric investigations revealed that copper nanoparticles impregnated on silica were thermally more stable compared to unsupported nanoparticles. Silica not only helps in maintaining the particle size but also makes nanoparticles stable at high temperatures due to its thick pore walls. Macro sized silica support also makes separation/handling of nanoparticles easy and simple

Evaluation of solid electrolytes: Development of conventional and interdisciplinary approaches

Abstract Solid‐state lithium batteries (SSLBs) have received considerable attention due to their advantages in thermal stability, energy density, and safety. Solid electrolyte (SE) is a key component in developing high‐performance SSLBs. An in‐depth understanding of the intrinsic bulk and interfacial properties is imperative to achieve SEs with competitive performance. This review first introduces the traditional electrochemical approaches to evaluating the fundamental parameters of SEs, including the ionic and electronic conductivities, activation barrier, electrochemical stability, and diffusion coefficient. After that, the characterization techniques to evaluate the structural and chemical stability of SEs are reviewed. Further, emerging interdisciplinary visualization techniques for SEs and interfaces are highlighted, including synchrotron X‐ray tomography, ultrasonic scanning imaging, time‐of‐flight secondary‐ion mass spectrometry, and three‐dimensional stress mapping, which improve the understanding of electrochemical performance and failure mechanisms. In addition, the application of machine learning to accelerate the screening and development of novel SEs is introduced. This review article aims to provide an overview of advanced characterization from a broad physical chemistry view, inspiring innovative and interdisciplinary studies in solid‐state batteries

Comparative Analysis of Ethylene/Diene Copolymerization and Ethylene/Propylene/Diene Terpolymerization Using Ansa-Zirconocene Catalyst with Alkylaluminum/Borate Activator: The Effect of Conjugated and Nonconjugated Dienes on Catalytic Behavior and Polymer Microstructure

The copolymerization of ethylene‒diene conjugates (butadiene (BD), isoprene (IP) and nonconjugates (5-ethylidene-2-norbornene (ENB), vinyl norbornene VNB, 4-vinylcyclohexene (VCH) and 1, 4-hexadiene (HD)), and terpolymerization of ethylene-propylene-diene conjugates (BD, IP) and nonconjugates (ENB, VNB, VCH and HD) using two traditional catalysts of C2-symmetric metallocene—silylene-bridged rac-Me2Si(2-Me-4-Ph-Ind)2ZrCl2 (complex A) and ethylene-bridged rac-Et(Ind)2ZrCl2 (complex B)—with a [Ph3C][B(C6F5)4] borate/TIBA co-catalyst, were intensively studied. Compared to that in the copolymerization of ethylene diene, the catalytic activity was more significant in E/P/diene terpolymerization. We obtained a maximum yield of both metallocene catalysts with conjugated diene between 3.00 × 106 g/molMt·h and 5.00 × 106 g/molMt·h. ENB had the highest deactivation impact on complex A, and HD had the most substantial deactivation effect on complex B. A 1H NMR study suggests that dienes were incorporated into the co/ter polymers’ backbone through regioselectivity. ENB and VNB, inserted by the edo double bond, left the ethylidene double bond intact, so VCH had an exo double bond. Complex A’s methyl and phenyl groups rendered it structurally stable and exhibited a dihedral angle greater than that of complex B, resulting in 1, 2 isoprene insertion higher than 1, 4 isoprene that is usually incapable of polymerization coordination. High efficiency in terms of co- and ter- monomer incorporation with higher molecular weight was found for complex 1. The rate of incorporation of ethylene and propylene in the terpolymer backbone structure may also be altered by the conjugated and nonconjugated dienes. 13C-NMR, 1H-NMR, and GPC techniques were used to characterize the polymers obtained

Recent Advances in Transition Metal Tellurides (TMTs) and Phosphides (TMPs) for Hydrogen Evolution Electrocatalysis

The hydrogen evolution reaction (HER) is a developing and promising technology to deliver clean energy using renewable sources. Presently, electrocatalytic water (H2O) splitting is one of the low-cost, affordable, and reliable industrial-scale effective hydrogen (H2) production methods. Nevertheless, the most active platinum (Pt) metal-based catalysts for the HER are subject to high cost and substandard stability. Therefore, a highly efficient, low-cost, and stable HER electrocatalyst is urgently desired to substitute Pt-based catalysts. Due to their low cost, outstanding stability, low overpotential, strong electronic interactions, excellent conductivity, more active sites, and abundance, transition metal tellurides (TMTs) and transition metal phosphides (TMPs) have emerged as promising electrocatalysts. This brief review focuses on the progress made over the past decade in the use of TMTs and TMPs for efficient green hydrogen production. Combining experimental and theoretical results, a detailed summary of their development is described. This review article aspires to provide the state-of-the-art guidelines and strategies for the design and development of new highly performing electrocatalysts for the upcoming energy conversion and storage electrochemical technologies