Hysteretic Room-Temperature Magnetic Bistability of the Crystalline 4,7-Difluoro-1,3,2-Benzodithiazolyl Radical.

The title radical R⋅, synthesized by reduction of the corresponding cation R, is thermally stable up to ~380 K in the crystalline state under anaerobic conditions. With SQUID magnetometry, single-crystal and powder XRD, solid-state EPR and TG-DSC, reversible spin-Peierls transition between diamagnetic and paramagnetic states featuring ~10 K hysteretic loop is observed for R⋅ in the temperature range ~310-325 K; ΔH=~2.03 kJ mol and ΔS=~6.

Reducibility of Al-Modified CoO: Influence of Aluminum Distribution.

The reduction of Co-based oxides doped with Al ions has been studied using in situ XRD and TPR techniques. Al-modified CoO oxides with the Al mole fraction Al/(Co + Al) = 1/6; 1/7.5 were prepared via coprecipitation, with further calcination at 500 and 850 °C.

Photocatalysts Based on Graphite-like Carbon Nitride with a Low Content of Rhodium and Palladium for Hydrogen Production under Visible Light.

In this study, we proposed photocatalysts based on graphite-like carbon nitride with a low content (0.01-0.5 wt.

Room temperature epoxidation of ethylene over delafossite-based AgNiO nanoparticles.

A mixed oxide of silver and nickel AgNiO was obtained co-precipitation in alkaline medium. This oxide demonstrates room temperature activity in the reaction of ethylene epoxidation with a high selectivity (up to 70%). Using the PDF method, it was found that the initial structure of AgNiO contains stacking faults and silver vacancies, which cause the nonstoichiometry of the oxide (Ag/Ni < 1).

Crystallization of SAPO-11 Molecular Sieves Prepared from Silicoaluminophosphate Gels Using Boehmites with Different Properties.

In this article, we report the results of research the formation of silicoaluminophosphate gels under changing gel aging conditions and the influence of an aluminum source (boehmite), characterized by different properties. The samples of initial gels were characterized by XRF, X-ray diffraction, MAS NMR Al and P, and scanning electron microscopy (SEM). Products of crystallization were characterized by XRF, X-ray diffraction, MAS NMR Al and P, scanning electron microscopy (SEM), N-physical adsorption, and IR spectroscopy with pyridine adsorption.

Efficient Photocatalytic Hydrogen Production over NiS-Modified Cadmium and Manganese Sulfide Solid Solutions.

In this work, new photocatalysts based on CdMnS sulfide solid solutions were synthesized by varying the fraction of MnS (x = 0.4, 0.6, and 0.

Nonstoichiometry Defects in Double Oxides of the ABO-Type.

Double oxides with the structure of the Ruddlesden-Popper (R-P) layered perovskite ABO attract attention as materials for various electrochemical devices, selective oxygen-permeable ceramic membranes, and catalytic oxidative reactions. In particular, SrTiO layered perovskite is considered a promising catalyst in the oxidative coupling of methane. Our high-resolution transmission electron microscopy (HRTEM) studies of SrTiO samples synthesized using various methods have shown that their structure often contains planar defects disturbing the periodicity of layer alternation.

Composite photocatalysts based on Cd Zn S and TiO for hydrogen production under visible light: effect of platinum co-catalyst location.

Ternary composite photocatalysts based on titania and solid solutions of CdS and ZnS were prepared and studied by a set of physicochemical methods including XRD, XPS, HRTEM, UV-vis spectroscopy, and electrochemical tests. Two synthetic techniques of platinization of Cd Zn S/TiO were compared. In the first case, platinum was deposited on the surface of synthesized Cd Zn S ( = 0.

Sol-Gel Synthesis and Characterization of the Cu-Mg-O System for Chemical Looping Application.

A sol-gel technique was applied to prepare the two-component oxide system Cu-Mg-O, where MgO plays the role of oxide matrix, and CuO is an active chemical looping component. The prepared samples were characterized by scanning electron microscopy, low-temperature nitrogen adsorption, and X-ray diffraction analysis. The reduction behavior of the Cu-Mg-O system was examined in nine consecutive reduction/oxidation cycles.

Dissecting the effects of water guest adsorption and framework breathing on the AlO(OH) centres of metal-organic framework MIL-53 (Al) by solid state NMR and structural analysis.

The relationship between the adsorption of water on MIL-53 (Al) MOF, the structural phase of MIL-53 (Al), and the quadrupole coupling constant of Al framework aluminium atom (QCC) of the MOF AlO(OH) centres (Al-sites) has been investigated by combining solid-state Al MAS NMR spectroscopy with XRD analysis and DFT calculations. It is established that Al QCC is primarily sensitive to water adsorption to the Al-sites and by a minor extent to the framework contraction/expansion interconversions. We thus conclude that the Al MAS NMR method is sensitive enough to differentiate the effects of pore contractions and water adsorption to Al-sites basing on the changes of the QCC value.

Comparative Study of the Photocatalytic Hydrogen Evolution over CdMnS and CdS-β-MnO-MnOOH Photocatalysts under Visible Light.

A series of solid solutions of cadmium and manganese sulfides, CdMnS (x = 0-0.35), and composite photocatalysts, CdS-β-MnO-MnOOH, were synthesized by precipitation with sodium sulfide from soluble cadmium and manganese salts with further hydrothermal treatment at 120 °C. The obtained photocatalysts were studied by the X-ray diffraction method (XRD), UV-vis diffuse reflectance spectroscopy, transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and N low temperature adsorption.

Impact of Incorporation of Active Nanoporous Components or Their Precursors in a CuAlO/CuAl Ceramometal Skeleton on the Properties in the Low-Temperature Water-Gas Shift Reaction.

Enhanced activity in low-temperature water-gas shift (LT-WGS) reaction of some ceramometal catalysts compared to conventional Cu-Zn-Al oxide catalyst was demonstrated. Porous ceramometals were synthesized from powdered CuAl alloys prepared by mechanical alloying with the addition of either CuAl powders produced by current spark explosion of Cu+Al wires or CuZnAl oxide obtained by coprecipitation. Their structural, microstructural, and textural characteristics were examined by means of X-ray diffraction, scanning electron microscopy with energy-dispersive X-ray spectrometry, NMR, and adsorption methods, and catalytic properties were studied in the LT-WGS reaction.

The influence of the sacrificial agent nature on transformations of the Zn(OH)/CdZnS photocatalyst during hydrogen production under visible light.

Photocatalysts based on zinc hydroxide and a solid solution of CdS and ZnS were prepared the precipitation method and used for photocatalytic hydrogen production from aqueous solutions of inorganic (NaS/NaSO) and organic (ethanol) sacrificial agents. The photocatalysts were tested in cyclic experiments for hydrogen evolution and studied using X-ray diffraction (XRD), UV-Vis diffuse reflectance spectroscopy, high-resolution transmission electron microscopy (HRTEM), energy-dispersive X-ray spectroscopy (EDX), and X-ray photoelectron spectroscopy (XPS) techniques. Different transformations of the β-Zn(OH) co-catalyst were observed in the presence of inorganic and organic sacrificial agents; namely, ZnS was formed in NaS/NaSO solution, whereas the formation of ε-Zn(OH) was detected in solution with ethanol.

Synthesis of CdZnS photocatalysts for gas-phase CO reduction under visible light.

Novel photocatalysts for CO2 reduction, which consist of a cadmium and zinc sulfide solid solution (Cd1-xZnxS), were successfully prepared by a simple two-step technique. The photocatalysts were characterized by X-ray diffraction, UV-VIS diffuse reflectance spectroscopy, and low-temperature N2 adsorption techniques and were tested in the gas-phase photocatalytic reduction of CO2 under visible light (λ = 450 nm). All the synthesized Cd1-xZnxS solid solutions were capable of enabling the chemical transformations of CO2 under the conditions considered.

On the influence of the metal loading on the structure of carbon-supported PtRu catalysts and their electrocatalytic activities in CO and methanol electrooxidation.

PtRu (1:1) catalysts supported on low surface area carbon of the Sibunit family (S(BET) = 72 m(2) g(-1)) with a metal percentage ranging from 5 to 60% are prepared and tested in a CO monolayer and for methanol oxidation in H(2)SO(4) electrolyte. At low metal percentage small (<2 nm) alloy nanoparticles, uniformly distributed on the carbon surface, are formed. As the amount of metal per unit surface area of carbon increases, particles start coalescing and form first quasi two-dimensional, and then three-dimensional metal nanostructures.

Synthesis and structural characterization of Se-modified carbon-supported Ru nanoparticles for the oxygen reduction reaction.

This work is part of a continued research aimed at the understanding of the promoting role of Se in the enhancement of the electrocatalytic activity of Ru in the oxygen reduction reaction. The objective of this paper is to systematically investigate the transformation of Ru nanoparticles upon their modification with the increasing amounts of Se. The Se-modified Ru/C samples with Se:Ru ratio from 0 to 1 were prepared by reacting carbon-supported Ru nanoparticles with SeO2 followed by reductive annealing and characterized using high-resolution transmission electron microscopy, energy-dispersive X-ray, X-ray diffraction analysis, X-ray photoelectron spectroscopy, and extended X-ray absorption fine structure.