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Abstract:
Efficient and sustainable energy conversion depends on the rational design of single-atom catalysts. The control of the active sites at the atomic level is vital for electrocatalytic materials in alkaline and acidic electrolytes. Moreover, fabrication of effective catalysts with a well-defined surface structure results in an in-depth understanding of the catalytic mechanism. Herein, a single atom ruthenium dispersed in nickel-cobalt layered hydroxide (Ru-NiCo LDH) is reported. Through the precise controlling of the atomic dispersion and local coordination environment, Ru-NiCo LDH//Ru-NiCo LDH provides an ultra-low overpotential of 1.45 mV at 10 mA cm−2 for the overall water splitting, which surpasses that of the state-of-the-art Pt/C/RuO2 redox couple. Density functional theory calculations show that Ru-NiCo LDH optimizes hydrogen evolution intermediate adsorption energies and promotes O-O coupling at a Ru-O active site for oxygen evolution, while Ni serves as the water dissociation site for effective water splitting. As a potential model, Ru-NiCo LDH shows enhanced water splitting performance with potential for the development of promising water-alkaline catalysts.

Abstract:
The rapidly growing production and usage of lithium-ion batteries (LIBs) dramatically raises the number of harmful wastes. Consequently, the LIBs waste management processes, taking into account reliability, efficiency, and sustainability criteria, became a hot issue in the context of environmental protection as well as the scarcity of metal resources. In this paper, we propose for the first time a functional material—a magnetorheological fluid (MRF) from the LIBs-based liquid waste containing heavy metal ions. At first, the spent battery waste powder was treated with acid-leaching, where the post-treatment acid-leaching solution (ALS) contained heavy metal ions including cobalt. Then, ALS was used during wet co-precipitation to obtain cobalt-doped superparamagnetic iron oxide nanoparticles (SPIONs) and as an effect, the harmful liquid waste was purified from cobalt. The obtained nanoparticles were characterized with SEM, TEM, XPS, and magnetometry. Subsequently, superparamagnetic nanoparticles sized 15 nm average in diameter and magnetization saturation of about 91 emu g−1 doped with Co were used to prepare the MRF that increases the viscosity by about 300% in the presence of the 100 mT magnetic fields. We propose a facile and cost-effective way to utilize harmful ALS waste and use them in the preparation of superparamagnetic particles to be used in the magnetorheological fluid. This work describes for the first time the second life of the battery waste in the MRF and a facile way to remove the harmful ingredients from the solutions obtained after the acid leaching of LIBs as an effective end-of-life option for hydrometallurgical waste utilization.

Keywords:
environment protection SPION, battery waste, toxic waste management, direct recycling, sustainability, circular economy, critical raw materials

Keywords:
Magnetorheological Fluids (MRF), rheology, smart materials, intelligent fluid, functional materials

Abstract:
Lithium-ion battery (LiB) waste powder is a valuable source of various materials, including carbon and metals. Although this material exhibits electrical conductivity, nanostructured morphology, and may contain metal oxides, it has not been used as an electrocatalyst. Here, we demonstrated the application of LiB waste powder as a catalyst for electrochemical H2O2 generation. The powder was both immobilized on a glassy carbon (GC) electrode and assembled at a liquid–liquid interface formed by decamethylferrocene (DMFc) solution in trifluorotoluene and aqueous perchloric acid in the presence of oxygen. The electrochemistry was studied by cyclic voltammetry and also with a rotating disk electrode (RDE), and a 2-electron ORR pathway was confirmed. H2O2 generation at the liquid–liquid interface and oxidation of DMFc were detected by colorimetry, UV–vis spectroscopy and scanning electrochemical microscopy (SECM). The use of LiB waste powder reduces the ORR onset potential by ca. 0.3 V compared to an unmodified GC. When assembled at a liquid–liquid interface the waste powder increases the efficiency of H2O2 generation by ca. 20 times.

Keywords:
hydrogen peroxide, lithium-ion battery waste, oxygen reduction, scanning electrochemical microscopy (SECM), liquid–liquid interface

Abstract:
Lithium-ion batteries (LIBs) waste is classified as a dangerous one. Fortunately, LIBs can be recycled and are already a valuable source of metals. This work is focused on the properties of the spent LIBs powder, which is a postproduct of the proposed organic leaching process and is presented as a source of nanocarbons with a unique structure. Furthermore, attention is paid to revealing the properties of the carbon component that can find a second life in other applications like photocatalysis or sorbents. Raman spectroscopy is used for the characterization of graphitic carbon. Scanning electron microscopy images are numerically quantitatively analyzed to provide additional parameters (for instance, the total length of edges) about the structure of materials, and X-ray diffraction (XRD) and energy-dispersive X-ray spectroscopy (EDS) further check their composition.

Keywords:
memory,memories,brain

Keywords:
ChemRAWN,electrocatalysis,electrochemical oxidation,ethanol,gold nanoparticles,nanobrush,nanowires,polyindole

Keywords:
Electrocatalysis, Ascorbic acid, Polyindole, Gold nanoparticles, Nanobrush, Hard-template synthesis