Molecular Precursor Routes for Ag-Based Metallic, Intermetallic, and Metal Sulfide Nanoparticles: Their Comparative ORR Activity Trend at Solid|Liquid and Liquid|Liquid Interfaces.

The electrochemical conversion of oxygen to water is a crucial process required for renewable energy production, whereas its first two-electron step produces a versatile chemical and oxidant─hydrogen peroxide. Improving performance and widening the limited selection of the potential catalysts for this reaction is a step toward the implementation of clean-energy technologies. As silver is known as one of the most effective catalysts of oxygen reduction reaction (ORR), we have designed a suitable molecular precursor pathway for the selective synthesis of metallic (Ag), intermetallic (Ag3Sb), and binary or ternary metal sulfide (Ag2S and AgSbS2) nanomaterials by judicious control of reaction conditions. The decomposition of xanthate precursors under different reaction conditions in colloidal synthesis indicates that carbon-sulfur bond cleavage yields the respective metal sulfide nanomaterials. This is not the case in the presence of trioctylphosphine when the metal-sulfur bond is broken. The synthesized nanomaterials were applied as catalysts of oxygen reduction at the liquid-liquid and solid-liquid interfaces. Ag exhibits the best performance for electrochemical oxygen reduction, whereas the electrocatalytic performance of Ag and Ag3Sb is comparable for peroxide reduction in an alkaline medium. Scanning electrochemical microscopy (SECM) analysis indicates that a flexible 2-electron to 4-electron ORR pathway has been achieved by transforming metallic Ag into intermetallic Ag3Sb.

Green composites based on volcanic red algae Cyanidiales, cellulose, and coffee waste biomass modified with magnetic nanoparticles for the removal of methylene blue.

In this paper, green nanocomposites based on biomass and superparamagnetic nanoparticles were synthesized and used as adsorbents to remove methylene blue (MB) from water with magnetic separation. The adsorbents were synthesized through the wet co-precipitation technique, in which iron-oxide nanoparticles coated the cores based on coffee, cellulose, and red volcanic algae waste. The procedure resulted in materials that could be easily separated from aqueous solutions with magnets. The morphology and chemical composition of the nanocomposites were characterized by SEM, FT-IR, and XPS methods. The adsorption studies of MB removal with UV-vis spectrometry showed that the adsorption performance of the prepared materials strongly depended on their morphology and the type of the organic adsorbent. The adsorption studies presented the highest effectiveness in neutral pH with only a slight effect on ionic strength. The MB removal undergoes pseudo-second kinetics for all adsorbents. The maximal adsorption capacity for the coffee@Fe3O4-2, cellulose@Fe3O4-1, and algae@Fe3O4-1 is 38.23 mg g-1, 41.61 mg g-1, and 48.41 mg g-1, respectively. The mechanism of MB adsorption follows the Langmuir model using coffee@Fe3O4 and cellulose@Fe3O4, while for algae@Fe3O4 the process fits to the Redlich-Peterson model. The removal efficiency analysis based on UV-vis adsorption spectra revealed that the adsorption effectiveness of the nanocomposites increased as follows: coffee@Fe3O4-2 > cellulose@Fe3O4-1 > algae@Fe3O4-1, demonstrating an MB removal efficiency of up to 90%.

Upcycling of Acid-Leaching Solutions from Li-Ion Battery Waste Treatment through the Facile Synthesis of Magnetorheological Fluid.

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.

Correction: Titania/chitosan-lignin nanocomposite as an efficient photocatalyst for the selective oxidation of benzyl alcohol under UV and visible light.

[This corrects the article DOI: 10.1039/D1RA06500A.].

Correction: Organic semiconductor perylenetetracarboxylic diimide (PTCDI) electrodes for electrocatalytic reduction of oxygen to hydrogen peroxide.

Correction for 'Organic semiconductor perylenetetracarboxylic diimide (PTCDI) electrodes for electrocatalytic reduction of oxygen to hydrogen peroxide' by Magdalena Warczak et al., Chem. Commun., 2018, 54, 1960-1963.

Correction: Organic semiconductor perylenetetracarboxylic diimide (PTCDI) electrodes for electrocatalytic reduction of oxygen to hydrogen peroxide.

Correction for 'Organic semiconductor perylenetetracarboxylic diimide (PTCDI) electrodes for electrocatalytic reduction of oxygen to hydrogen peroxide' by Magdalena Warczak et al., Chem. Commun., 2018, DOI: .

Organic semiconductor perylenetetracarboxylic diimide (PTCDI) electrodes for electrocatalytic reduction of oxygen to hydrogen peroxide.

Hydrogen peroxide is one of the most important industrial chemicals and there is great demand for the production of H2O2 using more sustainable and environmentally benign methods. We show electrochemical production of H2O2 by the reduction of O2, enabled by an organic semiconductor catalyst, N,N'-dimethyl perylenetetracarboxylic diimide (PTCDI). We make PTCDI cathodes that are capable of stable and reusable operation in aqueous electrolytes in a pH range of 1-13 with a catalytic figure of merit as high as 26 g H(2)O(2) per g catalyst per h. [corrected] These performance and stability open new avenues for organic small molecule semiconductors as electrocatalysts.

Conductive, capacitive, and viscoelastic properties of a new composite of the C60-pd conducting polymer and single-wall carbon nanotubes.

Thin films of a new composite of an electroactive fullerene-based (C60-Pd) polymer and HiPCO single-wall carbon nanotubes, which were noncovalently modified by 1-pyrenebutiric acid (pyr-SWCNTs), were electrochemically prepared under multiscan cyclic voltammetry conditions. With respect to blank polymer, superior conductive, capacitive, and viscoelasitic properties of the composite were demonstrated. Composition of pyr-SWCNTs was determined by thermogravimetric analyses, which showed one molecule of 1-pyrenebutiric acid per approximately 20 carbon atoms of SWCNT. Atomic force microscopy imaging revealed that pyr-SWCNTs form tangles of pyr-SWCNTs bundles surrounded by globular clusters of the C60-Pd polymer. Peaks characteristic of both pyr-SWCNTs (radial breathing modes at approximately 200 to 300 cm(-1)) and C60-Pd polymer in the Raman spectra recorded for the composite confirmed the presence of pyr-SWCNTs in the composite film. The mass of the deposited film was in situ measured by piezoelectric microgravimetry with the use of an electrochemical quartz crystal microbalance (EQCM). Then, curves of the current, resonant frequency change, and dynamic resistance change versus the potential in different potential ranges were simultaneously recorded in a blank acetonitrile solution of tetrabutylammonium perchlorate. Specific capacitance, determined at -1.20 V for the composite as 90 F g(-1), was twice as high as that for the polymer. Electrochemical impedance spectroscopy was used to determine impedance parameters of both the C60-Pd polymer and C60-Pd/pyr-SWCNTs composite film. This data analysis indicated increased capacitance and decreased resistance for the new composite film.