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Titanium oxides have been considered potential electrode materials for pseudocapacitors because of their exceptional properties, such as high thermal and chemical stabilities, ready availability and low cost. However, they are not ideal for practical applications due to their poor ionic and electrical conductivity. The electrochemical performance of TiO2 can be greatly improved if the material is nanotextured by reducing the particle size in optimizing the synthesis pathway. Actually, for metallic oxides, the electrochemical performance significantly depends on the particle size/morphology. At relatively low current densities the higher capacity values are exhibited by noncrystalline TiO2 having 2 nm particle size, with values reaching 704 C g−1. However, only thin electrodes are able to operate at a high charge density, limiting the energy density of the final device. Here, we propose a solution to circumvent such a drawback by further nanotexturing TiO2 over multiwalled carbon nanotubes (CNTs). For that purpose, CNTs were introduced during oxide preparation. The synthesis protocol has been optimized for obtaining a uniform coverage of small TiO2 particles on the surface of the CNTs. At low current densities, high mass loading TiO2/CNT composites electrodes are able to deliver capacitances as high as 480 F g−1 and the presence of CNTs allows keeping 70% of the capacitance at high current densities while only 27% is retained when using a regular conductivity agent as carbon black. The results demonstrate that uniform nanotexturation of TiO2 over CNTs allows good rate capabilities to be obtained for thick electrodes having sufficient active material loading to achieve high specific energy and power densities.

In this study, styrene butadiene rubber (SBR) was devulcanized using microwave irradiation. In particular, effect of ionic liquid (IL), pyrrolidinium hydrogen sulfate [Pyrr][HSO4], on the devulcanization performance was studied. It was observed that the evolution of the temperature reached by rubber powder exposed to microwave irradiation for different energy values was favored by the presence of ionic liquid [Pyrr][HSO4] significantly over the whole range of the microwave energy values. Beyond the threshold point of 220 Wh/kg, the soluble fraction after devulcanization sharply increased with increasing devulcanization microwave energy. For the powder mixed with [Pyrr][HSO4], the increase was more significant. Furthermore, the crosslink density was observed to decrease slowly with the microwave energy up to 220 Wh/kg, beyond which the crosslink density decreased significantly for the rubber impregnated with IL. For the rubber with IL, significant and continuous increase in Tg with microwave energy values was observed in comparison with the SBR where no change in transition temperature was observed. Mechanical shearing of rubber gums in the two-roll mill favored the devulcanization process, which indicated that the combination of mechanical loading with microwave energy and IL is an efficient procedure allowing an optimal devulcanization of rubbers.

We have investigated the influence of oxygen excess on structural and physical properties of the Nd2NiO4+δ compounds. Using the citrate method and subsequent annealing in air and in a reducing atmosphere a various oxygen-doped compounds were prepared. X-ray diffraction at room temperature shows that structure is strongly oxygen excess dependent. Thus, by increasing δ by up to 0.077, the compounds adopt a tetragonal structure gradually with a biphasic domain between orthorhombic and tetragonal structures. And at higher δ values, the structure becomes orthorhombic. Moreover, Rietveld analysis shows that for δ<0.077 the presence of two crystalline phases with different oxygen excess: it should be the signature of interstitial oxygen, which is distributed in heterogeneous way. The biphasic products are composed of a stoichiometric Nd2NiO4 phase (orthorhombic structure) and a tetragonal Nd2NiO4.077 phase. Magnetic susceptibility shows a deviation from Curie–Weiss law for lower oxygen excess (δ0.077). Moreover, some anomalies in dc magnetic susceptibility curves was observed at 45, 95 and 130 K for δ<0.077. These transitions are connected to the tetragonal phase, and were attributed, respectively, to an antiferromagnetic transition, possible charge ordering and structural transition. [Copyright &y& Elsevier]

The purpose of the study was to investigate the synthesis of economic calcium phosphate powders from recycled oyster shells, using a ball milling method. The oyster shell powder and a calcium pyrophosphate powder were used as starting materials and ball milled, then heat treated at 1,050°C for 5 h to produce calcium phosphate powders through a solid-state reaction. Electrochemically synthesized mesoporous silicon microparticles were then added to the prepared phosphate powders by mechanical mixer. The final powders were characterized using X-ray diffraction, Fourier transform infrared spectroscopy, and scanning electron microscopy to analyze their chemical composition and determine the most suitable process conditions. The biocompatibility of the produced powders was also tested in vitro using murine cells and the results showed good biocompatibility., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Richard, Alfred-Arulrasa, Ramadas, Mahagamage, Defforge, Gaultier, Autret-Lambert, Poirot, Champion and Magnaudeix.)

The elimination of rubber wastes without affecting the environment is one of the most important challenges of the 21st century waste management. Accordingly, the present work is focused on the recycling of natural rubber (NR) industry waste by means of devulcanization in supercritical carbon dioxide (scCO 2 ) atmosphere. With that aim, a novel device allowing to perform rubber devulcanization was developed. It consists of a triaxial compression reactor integrated into a dynamic hydraulic universal testing machine with a heating chamber. NR industry waste was devulcanized in the mentioned device at different temperatures, in scCO 2 by using diphenyl disulfide (DD) as devulcanizing reagent. The devulcanization degree and quality of the treated materials were evaluated by the swelling test combined with the Horikx theory. It was appeared that a successful devulcanization, with almost no degradation, was obtained, and the devulcanization degree reached maximum value of ~90%. Thermogravimetric tests and scanning electron microscopy (SEM) images strengthened these results. Finally, it was concluded that the developed device is appropriate to perform rubber recycling, which contributes to the progress in the environmental protection., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)