Storing and transporting pressurized or liquid hydrogen is expensive and hazardous. As a result, safer methods, such as chemical storage in ammonia, are becoming increasingly important. However, the instantaneous start of a conventionally heated decomposition reactor is challenging.
View Article and Find Full Text PDFPlatinum particle growth during long-term operations is one of the well-known bottlenecks offsetting the performance and stability of Pt-based electrocatalysts in polymer electrolyte membrane (PEM) fuel cells and PEM water electrolyzers. In this research, the addition of certain ceramic nanoparticulate additives to the catalyst ink was evaluated as a means of improving the electrochemical stability of a carbon-supported platinum (Pt/C) electrocatalyst in gas diffusion electrodes (GDEs) during an accelerated stress test (AST). GDEs prepared using three nanoparticulate ceramic additives (TiN, ATO, and TiO) with three loadings (replacing 5, 10, and 15 wt % of the catalyst) were studied for their electrochemical performance, i.
View Article and Find Full Text PDFEnhancing iridium (Ir)-based electrocatalysts to achieve high activity and robust durability for the oxygen evolution reaction (OER) in acidic environments has been an ongoing mission in the commercialization of proton exchange membrane (PEM) electrolyzers. In this study, we present the synthesis of carbon-supported Ir nanoparticles (NPs) using a modified impregnation method followed by solid-state reduction, with Ir loadings of 20 and 40 wt % on carbon. Among the catalysts, the sample with an Ir loading of 20 wt % synthesized at 1000 °C with a heating rate of 300 °C/h demonstrated the highest mass-normalized OER performance of 1209 A g and an OER current retention of 80% after 1000 cycles of cyclic voltammetry (CV).
View Article and Find Full Text PDFExamining the critical role of anticoagulants in medical practice, particularly their central function in preventing abnormal blood clotting, is of the utmost importance. However, the study of interactions between blood proteins and alternative anticoagulant nano-surfaces is still understood poorly. In this study, novel approach involving direct functionalisation of magnetic iron oxide nanoparticles (MNPs) as carriers with sulphated dextran (s-dext) is presented, with the aim of evaluating the potential of magnetically-responsive MNPs@s-dext as anticoagulants.
View Article and Find Full Text PDFElectrochemical water splitting under acidic conditions is a clean way towards producing hydrogen fuels. The slow kinetics of the oxygen evolution reaction (OER) at the anode is currently a bottleneck for commercial acceptance of this technology. Therefore, arriving at more efficient and sustainable OER electrocatalysts is highly desirable.
View Article and Find Full Text PDFThe development of efficient, chemical hydrogen-storage materials is one of the greatest technical challenges for the coming hydrogen-based economy. Analyzed liquid organic hydrogen carriers (LOHCs), which bond, store, and release the H molecules through catalytic hydrogenation, cracking, and dehydrogenation cycles, are being considered as an alternative, functional option. The search for a highly industrialized reactive production process, coupled with the use of renewable electrical energy, has encouraged the consideration of characteristic stand-alone methods (such as microwave-assisted surface reactions, an increase in the rates by magnetic heating systems, electrocatalysis, variable photochemical manufacturing, and plasma).
View Article and Find Full Text PDFPolyacrylic acid (PAA)-coated magnetic nanoparticles (MNP@PAA) were synthesized and evaluated as draw solutes in the forward osmosis (FO) process. MNP@PAA were synthesized by microwave irradiation and chemical co-precipitation from aqueous solutions of Fe and Fe salts. The results showed that the synthesized MNPs have spherical shapes of maghemite FeO and superparamagnetic properties, which allow draw solution (DS) recovery using an external magnetic field.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
August 2023
Ethylene epoxidation is industrially and commercially one of the most important selective oxidations. Silver catalysts have been state-of-the-art for decades, their efficiency steadily improving with empirical discoveries of dopants and co-catalysts. Herein, we perform a computational screening of the metals in the periodic table, identify prospective superior catalysts and experimentally demonstrate that Ag/CuPb, Ag/CuCd and Ag/CuTl outperform the pure-Ag catalysts, while they still confer an easily scalable synthesis protocol.
View Article and Find Full Text PDFIn recent years, various types of radiosensitizers have been developed to address the challenges of cancer radiotherapy. Here, platinum-functionalized oxygenated single-walled carbon nanotubes (O-SWCNTs-Pt) coated with folic acid (FA) and bovine serum albumin (BSA) (O-SWCNTs-Pt-BSA-FA) were synthesized, characterized, and used as radiosensitizers to improve the therapeutic efficacy of X-rays in a mouse model of breast cancer (4T1) in vitro. The nanosensitizer was characterized by different techniques, such as transmission electron microscopy (TEM), selected area electron diffraction (SAED), dynamic light scattering (DLS), zeta potential, X-ray diffraction (XRD), ultraviolet-visible (UV-visible), and Fourier transform infrared (FTIR) spectrometry.
View Article and Find Full Text PDFWe have synthesized a novel, bis-bidentate, covalently anchored, 4,6-diacetyl resorcinol (DAR) ligand on silica-coated magnetic FeO nanoparticles and the corresponding bi-metallic iron(iii) complex (FeO@SiO-APTESFeL). Both the chemical nature and the structure of the homogeneously heterogenized catalyst were investigated using physico-chemical techniques. The results obtained by XPS, XRD, FT-IR, TGA, VSM, SEM, TEM, EDX, ICP and AAS revealed a magnetic core, a silica layer and the grafting of a binuclear iron complex on the FeO@SiO-APTES, as well as its thermodynamic stability.
View Article and Find Full Text PDFPlastic waste has become a major global environmental concern. The utilization of solid waste-derived porous carbon for energy storage has received widespread attention in recent times. Herein, we report the comparison of electrochemical performance of porous carbon foams (CFs) produced from waste polyurethane (PU) elastomer templates via two different activation pathways.
View Article and Find Full Text PDFTwo different morphologies of ferroelectric bismuth titanate (BiTiO) nanoparticles, , nanoplatelets and nanowires, were synthesized by changing the concentration of NaOH during a hydrothermal treatment of precipitated Ti and Bi ions. The nanoparticles' crystal structures were characterized using atomic-resolution imaging with a -probe-corrected scanning-transmission electron microscope in combination with X-ray diffractometry and Raman spectroscopy. The nanoplatelets (10 nm thick and from 50 nm to 200 nm wide) exhibit the Aurivillius-type layered-perovskite crystal structure that is characteristic of BiTiO, whereas the nanowires (from 15 nm to 35 nm wide and from several hundreds of nm to several μm long) exhibit an entirely new structure with an orthorhombic unit cell ( = 3.
View Article and Find Full Text PDFIn this study, citric acid (CA)-coated magnetite FeO magnetic nanoparticles (FeO@CA MNPs) for use as draw solution (DS) agents in forward osmosis (FO) were synthesized by co-precipitation and characterized by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), dynamic light scattering (DLS), transmission electron microscopy (TEM) and magnetic measurements. Prepared 3.7% / colloidal solutions of FeO@CA MNPs exhibited an osmotic pressure of 18.
View Article and Find Full Text PDFThe paper reports the synthesis of nickel tellurides via a mechanochemical method from elemental precursors. NiTe, NiTe, and NiTe were prepared by milling in stainless steel vials under nitrogen, using milling times from 1 h to 12 h. The products were characterized by powder X-ray diffraction (pXRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDX), dynamic light scattering (DLS), vibrating sample magnetometer (VSM), UV-VIS spectrometry, and thermal analysis (TGA and DSC).
View Article and Find Full Text PDFUpconverting nanoparticles (UCNPs) are being extensively investigated for applications in bioimaging because of their ability to emit ultraviolet, visible, and near-infrared light. NaYF4 is one of the most suitable host matrices for producing high-intensity upconversion fluorescence; however, UCNPs based on NaYF4 are not chemically stable in aqueous media. To prevent dissolution, their surfaces should be modified.
View Article and Find Full Text PDFThe pollution of environmental systems with heavy metals is becoming a serious problem worldwide. These contaminants are one of the main issues in sludge (which is considered waste) and can even have harmful effects if the sludge is not treated properly. Thus, the development of a novel functional magnetic nanoadsorbent based on a derived lysine is reported here, which can be efficiently applied for metal removal from sludge.
View Article and Find Full Text PDFUtilization of magnetic nanoparticle-mediated conversion of electromagnetic energy into heat is gaining attention in catalysis as a source of heat needed for a substrate's chemical reaction (electrification of chemical conversions). We demonstrate that rapid and selective heating of magnetic nanoparticles opens a way to the rapid synthesis of a nanocatalyst. Magnetic heating caused rapid reduction of Ru cations in the vicinity of the support material and enabled preparation of a Ru nanoparticle-bearing nanocatalyst.
View Article and Find Full Text PDFThe synthesis of magnetic nanoparticles (MNPs) coated with hydrophilic poly-sodium-acrylate (PSA) ligands was studied to assess PSA-MNP complexes as draw solution (DS) solutes in forward osmosis (FO). For MNP-based DS, the surface modification and the size of the MNPs are two crucial factors to achieve a high osmolality. Superparamagnetic nanoparticles (NP) with functional groups attached may represent the ideal DS where chemical modifications of the NPs can be used in optimizing the DS osmolality and the magnetic properties allows for efficient recovery (DS re-concentration) using an external magnetic field.
View Article and Find Full Text PDFMaterials (Basel)
February 2019
Magnetic fluid hyperthermia (MFH) is a medical treatment where the temperature in the tissue is increased locally by means of heated magnetic fluid in an alternating magnetic field. In recent years, it has been the subject of a lot of research in the field of Materials, as well as in the field of clinical testing on mice and rats. Magnetic fluid manufacturers aim to achieve three objectives; high heating capacity, biocompatibility and self-regulatory temperature effect.
View Article and Find Full Text PDFDue to the extreme rise of sludge pollution with heavy metals (e.g. copper), the options for its disposal or treatment are decreasing.
View Article and Find Full Text PDFA process to recycle platinum from industrial waste, for example, spent catalysts from polymer fuel cells and electrolyzers, through potentiodynamic dissolution along with potentiostatic electrodeposition in dilute acidic/acid-free baths has been explored. During potentiodynamic dissolution, owing to Ostwald ripening, redeposition of the dissolved Pt species on source nanoparticles becomes significant, leading to lower overall dissolution efficiency. Alternatively, high concentrations of Pt-complexing agents (e.
View Article and Find Full Text PDFAn understanding of the adaptation of the crystal structure of materials confined at the nanoscale, the influences of their specific structures on the evolution of their morphologies and, finally, their functional properties is essential not only for expanding fundamental knowledge, but also for facilitating the designs of novel nanostructures for diverse technological and medical applications. Here we describe how the distinct structure of barium-hexaferrite nanoplatelets evolves in a stepwise manner in parallel with the development of their size and morphology during hydrothermal synthesis. The nanoplatelets are formed by reactions between Ba- and Fe-hydroxides in an aqueous suspension at temperatures below 80 °C.
View Article and Find Full Text PDFNanocomposites with a high, uniform loading of magnetic nanoparticles are very desirable for applications such as electromagnetic shielding and cancer treatment based on magnetically induced hyperthermia. In this study, a simple and scalable route for preparing nanocomposites with a high, uniform loading of magnetic nanoparticles is presented. The magnetic iron-oxide nanoparticles were functionalized with a methacrylate-based monomer that copolymerized in a toluene solution with the methyl methacrylate (MMA) monomer.
View Article and Find Full Text PDFAtomic-resolution scanning-transmission electron microscopy showed that barium hexaferrite (BHF) nanoplatelets display a distinct structure, which represents a novel structural variation of hexaferrites stabilized on the nanoscale. The structure can be presented in terms of two alternating structural blocks stacked across the nanoplatelet: a hexagonal (BaFeO) R block and a cubic (FeO) spinel S block. The structure of the BHF nanoplatelets comprises only two, or rarely three, R blocks and always terminates at the basal surfaces with the full S blocks.
View Article and Find Full Text PDFNickel and cobalt sulfides are promising materials in different cutting-edge research areas like solar cells, supercapacitors, catalysts, and electrode materials. Nickel and cobalt sulfides with various stoichiometries have been synthesized sonochemically from Ni(CHCOO) ∙ 4HO, Co(CHCOO) ∙ 2HO and different sulfur precursors using a direct immersion ultrasonic probe. The products were characterized by X-ray powder diffraction, transmission electron microscopy (TEM) including EDX analysis, IR and UV-Vis spectroscopy and elemental analysis.
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