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In the recycling of end-of-life rare-earth magnets, the recovery of non-rare earth constituents is often neglected. In the present study, strong cation and anion exchange resins were tested batchwise for the recovery of the non-rare-earth constituents of permanent magnets (copper, cobalt, manganese, nickel and iron) from synthetic aqueous and ethanolic solutions. The cation exchange resin recovered most of metal ions from aqueous and ethanolic feeds, whereas the anion exchange resin could selectively recover copper and iron from ethanolic feeds. The highest uptake of iron and copper was found for 80 vol% and 95 vol% multi-element ethanolic feeds, respectively. A similar trend in selectivity of the anion resin was observed in breakthrough curve studies. Batch experiments, UV-Vis, FT-IR and XPS studies were performed to elucidate the ion exchange mechanism. The studies indicate that the formation of chloro complexes of copper and their exchange by the (hydrogen) sulfate counter ions of the resin have an important role in the selective uptake of copper from the 95 vol% ethanolic feed. Iron(II) was largely oxidized to iron(III) in ethanolic solutions and was expected to be recovered by the resin in the form of iron(II) and iron(III) complexes. The moisture content of the resin did not have a significant role on the selectivity for copper and iron., 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 © 2023 Elsevier Ltd. All rights reserved.)

Catalytic materials are the greatest challenge for the commercial application of water electrolysis (WEs) and fuel cells (FCs) as clean energy technologies. There is a need to find an alternative to expensive and unavailable platinum group metal (PGM) catalysts. This study aimed to reduce the cost of PGM materials by replacing Ru with RuO 2 and lowering the amount of RuO 2 by adding abundant and multifunctional ZnO. A ZnO@RuO 2 composite in a 10:1 molar ratio was synthesized by microwave processing of a precipitate as a green, low-cost, and fast method, and then annealed at 300°C and 600°C to improve the catalytic properties. The physicochemical properties of the ZnO@RuO 2 composites were investigated by X-ray powder diffraction (XRD), Raman and Fourier transform infrared (FTIR) spectroscopy, field emission scanning electron microscopy (FESEM), UV-Vis diffuse reflectance spectroscopy (DRS), and photoluminescence (PL) spectroscopy. The electrochemical activity of the samples was investigated by linear sweep voltammetry in acidic and alkaline electrolytes. We observed good bifunctional catalytic activity of the ZnO@RuO 2 composites toward HER and OER in both electrolytes. The improved bifunctional catalytic activity of the ZnO@RuO 2 composite by annealing was discussed and attributed to the reduced number of bulk oxygen vacancies and the increased number of established heterojunctions., 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 Aleksić, Stojković Simatović, Stanković, Veselinović, Stojadinović, Rac, Radmilović, Rajić, Škapin, Mančić and Marković.)

This paper reports a detailed study of crystal structure and dielectric properties of ruthenium-substituted calcium-copper titanates (CaCu 3 Ti 4- x Ru x O 12 , CCTRO). A series of three samples with different stoichiometry was prepared: CaCu 3 Ti 4- x Ru x O 12 , x = 0, 1 and 4, abbreviated as CCTO, CCT3RO and CCRO, respectively. A detailed structural analysis of CCTRO samples was done by the Rietveld refinement of XRPD data. The results show that, regardless of whether Ti 4+ or Ru 4+ ions are placed in B crystallographic position in AA ' 3 B 4 O 12 (CaCu 3 Ti 4- x Ru x O 12 ) unit cell, the crystal structure remains cubic with Im3¯ symmetry. Slight increases in the unit cell parameters, cell volume and interatomic distances indicate that Ru 4+ ions with larger ionic radii (0.62 Å) than Ti 4+ (0.605 Å) are incorporated in the CaCu 3 Ti 4- x Ru x O 12 crystal lattice. The structural investigations were confirmed using TEM, HRTEM and ADF/STEM analyses, including EDXS elemental mapping. The effect of Ru atoms share in CaCu 3 Ti 4- x Ru x O 12 samples on their electrical properties was determined by impedance and dielectric measurements. Results of dielectric measurements indicate that one atom of ruthenium per CaCu 3 Ti 4 -x Ru x O 12 unit cell transforms dielectric CCTO into conductive CCT3RO while preserving cubic crystal structure. Our findings about CCTO and CCT3RO ceramics promote them as ideal tandem to overcome the problem of stress on dielectric-electrode interfaces in capacitors.