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An unprecedented method has been developed to obtain heterometallic‐organophosphine frameworks (HMOPFs) through a solvent‐free, three‐component mechanochemical process. In a ball mill, mixing copper (I) bromide with zinc (II), nickel (II) or copper (II) acetates, in the presence of (PTA‐CH2‐C6H4‐p‐COOH) Br (PTA is 1,3,5‐triaza‐7‐phosphaadamantane) as an organic linker, has produced the corresponding HMOPFs based on Cu+‐Zn2+, Cu+‐Ni2+ and Cu+‐Cu2+, respectively. The pyrolysis of HMOPFs resulted in bimetallic nanoparticles of transition metal phosphide and phosphate embedded in multi‐P,N,Br‐codoped carbon matrices (Cu−M@C). Due to the utilization of an aminophosphine organic linker, this HMOPFs‐derived approach typifies an eco‐friendly synthesis of carbon confined transition metal phosphides or phosphates. It avoids the common conventional methods that involves phosphorylation using large amounts of additional P sources, which leads to an intensive release of the flammable and poisonous phosphine gas. Also, the presence of Br at the organic linker eliminates the need for using bromine vapours to obtain halogen‐doped carbon matrices. The Cu−M@C nanocomposites were tested as negative electrode materials for asymmetric supercapacitors. Electrochemical tests included cyclic voltammetry and galvanostatic charge‐discharge experiments, which revealed the Cu−Zn@C electrode with a higher potential window as compared to Cu−Ni@C and Cu−Cu@C electrodes, achieving a rate performance of 60 % and high coulombic efficiency. [ABSTRACT FROM AUTHOR]

Nanostructured Cobalt‐Actinide (An=Th, U) bimetallic oxides were for the first time prepared by the epoxide addition method and electrospinning technique aiming the synthesis of aerogels and nanofibers, respectively. Tested as catalysts for the methanation of CO2 and regardless of the actinide element, the yield and selectivity towards CH4 are high (>40 and 95 %, respectively), which was explained by their physicochemical properties such as reducibility and basicity and the existence of a synergic effect between cobalt and actinide species. The aerogels present the best catalytic behavior, namely those with thorium and the catalytic activity increases with the Co/An molar ratio. Both aerogels and nanofibers also present a high resistance to deactivation for at least 75 h in the gaseous stream, which is an advantage for any catalytic application. Moreover, at 300 °C they are 2 to 4 times more active than two reference catalysts (5wt % Rh/Al2O3 and NiO/Al2O3) tested in the same conditions, which to our best knowledge is a significant result. [ABSTRACT FROM AUTHOR]

ZnMn2O4 spinels are prepared by a simple hydrothermal route with control of the reaction time, ranging from 6 h to 18 h. The evolution of the structural and morphological parameters under the effect of time was analyzed by XRD, ATR-FTIR, XPS, and SEM-EDS. The XRD results show that for longer reaction times (18 h), the ZnMn2O4 spinel samples present a tetragonal structure with high crystallinity and an average crystallite size of 32.3 ± 1.7 nm, larger than those obtained for 6 h and 12 h. The ATR-FTIR spectra confirm the structural results, with well-defined peaks related to stretching vibrations of M-O (M = Zn, Mn) functional groups. XPS reveals the co-existence of several metal oxides and hydroxides at the outermost surface. SEM analysis shows that the samples present a pyramid morphology, better defined at 18 h, with an average particle size of 6.2 ± 1.5 µm. EDS analysis of ZnMn2O4 (18 h) reveals atomic ratios of 0.45, 0.22, and 0.50 for Zn/Mn, Zn/O, and Mn/O, respectively, in good agreement with the expected values. Based on the CVs, the synthesized ZnMn2O4 samples formed at 18 h showed the most promising electrochemical properties, with a specific capacity of 102 F g−1, offering great potential in supercapacitor applications. [ABSTRACT FROM AUTHOR]

For the first time, a magnetic C-scorpionate catalyst was prepared from the iron(II) complex [FeCl2{κ3-HC(pz)3}] (pz = pyrazol-1-yl) and ferrite, using the sustainable mechanochemical synthetic procedure. Its catalytic activity for the cyclohexane oxidation with tert-butyl hydroperoxide (TBHP) was evaluated in different conditions, namely under microwave irradiation and under the effect of an external magnetic field. The use of such magnetic conditions significantly shifted the catalyst alcohol/ketone selectivity, thus revealing a promising, easy new protocol for tuning selectivity in important catalytic processes. [ABSTRACT FROM AUTHOR]

TiO2 has an easily tunable bandgap and a great absorption dye ability being widely used in many fields and in a number of fascinating applications. In this study, a wet chemical route, particularly a sol gel method using spin-coating is adopted to deposit TiO2 thin films onto soda lime glass and silicon substrates. TiO2 films were prepared by using an alcoholic solution of analytical reagent grade TiCl4 as titanium precursor at various experimental conditions. The accent was put on the conditions of preparation (spin time, spin speed, precursor concentration, number of coating layers etc), doping and on the post-deposit treatment namely the drying and the crystallization. The results showed a strong dependence on the drying temperature and on the temperature and duration of the crystallization. We found that the solution preparation and its color are important for getting a reproducible final product. The Raman spectra recorded at room temperature, showed the characteristic peaks of anatase which appear at 143 and around 396 cm-1. These peaks confirm the presence of TiO2. The X-ray diffraction (XRD) was used to identify the crystalline characteristic of TiO2 while the chemical states and relative amounts of the main elements existing in the samples were investigated by X-ray Photoelectron Spectroscopy (XPS). The morphology of the samples was visualized by AFM. We show by this work the feasibility to obtain different nanostructured TiO2 by changing the concentration of the solution. Photocatalytic activity of TiO2 films was evaluated. Rhodamine B is a recalcitrant dye and TiO2 was successfully tested for its oxidation. An abatement of 60% was obtained under sunlight for an initial concentration of 10 mg/l. [ABSTRACT FROM AUTHOR]

Gold nanoparticles (AuNPs) were prepared using an eco-friendly approach in a single step by reduction of HAuCl4 with polyphenols from tea extracts, which act as both reducing and capping agents. The obtained AuNPs were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), ultraviolet–visible spectroscopy (UV–vis), and X-ray photoelectron spectroscopy (XPS). They act as highly efficient catalysts in the reduction of various aromatic nitro compounds in aqueous solution. The effects of a variety of factors (e.g., reaction time, type and amount of reducing agent, shape, size, or amount of AuNPs) were studied towards the optimization of the processes. The total polyphenol content (TPC) was determined before and after the catalytic reaction and the results are discussed in terms of the tea extract percentage, the size of the AuNPs, and their catalytic activity. The reusability of the AuNP catalyst in the reduction of 4-nitrophenol was also tested. The reactions follow pseudo first-order kinetics. [ABSTRACT FROM AUTHOR]

Molybdenum disulphide (MoS 2 ) is a layered material with interesting photocatalytic properties. In this study, a layered MoS 2 was produced using a hydrothermal method. The obtained material was characterised by XRD (X-ray diffraction), XPS (X-ray photoelectron spectroscopy), SEM (scanning electron microscopy), UV-Vis spectroscopy, DLS (dynamic light scattering), and zeta potential analysis. For the evaluation of the photocatalytic properties of layered MoS 2 , a solution of bromophenol blue (BPB) and the catalyst was illuminated for 120 minutes. According to the experimental results, MoS 2 exhibited excellent catalytic activity in BPB degradation. The MoS 2 preparation method enabled improved light harvesting, avoided fast charge recombination (related to bulk MoS 2 ), and created a large number of suitable electron transfer sites for photocatalytic reactions. Simulation of BPB decay and bromide production was carried out for a further understanding of MoS 2 photocatalytic action. The simulation results proved the reduction mechanism of BPB photodegradation., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)