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Herein, we synthesized Ti-MOF through a solvothermal method and subsequently calcined it to form anatase TiO2. We further developed a Bi2O3@TiO2 mixed oxide using impregnation and calcination processes. These oxides showed significant photocatalytic activity for degrading Eriochrome Black T (EBT) dye under visible light irradiation. We characterized the prepared samples using various techniques, including XRD, XPS, FTIR, BET, SEM, EDX, TEM, and UV-DRS analyses. Our results indicated that TiO2 and 10%Bi2O3@TiO2 achieved 80% and 100% degradation of EBT dye solution (50 ppm) within 30 min in acidic medium with a 50 mg catalyst dose, respectively. The calcination of the Ti-MOF into TiO2 improved its sensitivity to visible light. The Bi2O3@TiO2 composite was also effective in degrading other organic pollutants, such as Congo Red (degradation ~99%), Malachite Green (degradation ~95%), Methylene Blue (degradation ~81%), and Safranine O (degradation ~69%). The impregnation of Bi2O3 increased the surface acidity of TiO2, enhancing its photocatalytic activity by promoting hydroxyl group formation through increased water adsorption. Additionally, 10%Bi2O3@TiO2 demonstrated excellent chemical stability and reusability, maintaining high degradation efficiency over four cycles. Density Functional Theory (DFT) and Time-Dependent DFT (TD-DFT) calculations were performed to understand the degradation mechanisms. UV-Vis absorption spectrum simulations suggested that the anionic HEB−2 (O24) or EB−3 forms of the EBT dye are likely to undergo degradation. This study highlights the potential of Bi2O3@TiO2 composites for effective photocatalytic applications in environmental remediation. [ABSTRACT FROM AUTHOR]

In this study, V2O5, 5ZnO/10V2O5, and ZnO, 10ZnO/10V2O5 nanocomposites were synthesized by the sol–gel method. The sol–gel technique is an important process for the fabrication of advanced oxide materials with desirable catalytic, optical, and structural properties. The varieties and flexibilities of sol–gel techniques help in preparing materials with extremely specific properties. For the presented samples, three types of phases were assessed. The average crystalline size of V2O5, 5ZnO/10V2O5 and ZnO, 10ZnO/10V2O5 nanocomposites were found to be 25, 26, 14.5, and 15.5 nm, respectively. SEM images showed three different shapes of semi-tube, semi-spherical, and semi-flower. The pure samples of V2O5 and ZnO showed semi-tube shapes. 5ZnO/10V2O5 shows a spherical shape with average dimeter of 0.6 µm. Strong dependence of the direct optical band gap was observed on different compositions that varied within the range of (2.33–2.73 eV). Conversely, the indirect values varied within the range of 2.119–2.35 eV. On the other hand, 10ZnO/10V2O5 has semi flower shape with different layers. Optical parameters, such as optical band gap, extension coefficient, tails of localized states, and refractive index, were gauged for these nanocomposites. In addition, the mean refractive index of ZnO is lower than that of V2O5, with differences observed between 5ZnO/10V2O5 and 10ZnO/10V2O5 nanocomposites.

Acid–base M2+MgAlO and M2+AlO mixed oxides (where M2+ = Mg, Cu, Co, Zn, and Ni) were obtained by thermal decomposition of the corresponding layered double hydroxide (LDH) precursors and used as catalysts for cyclohexanol and benzaldehyde condensation under solvent-free conditions. The catalysts were characterized by X-ray diffraction (XRD), X-ray fluorescence (XRF), scanning electron microscopy (SEM), and temperature-programmed desorption of CO2 (TPD-CO2). Gas chromatography–mass spectroscopy (GC/MS) was used for the identification and quantification of the product mixtures. In the reaction of cyclohexanol and benzaldehyde on M2+MgAlO and MgAlO catalysts, a 2,6-dibenzylidene-cyclohexanone was obtained as the main product as a result of consecutive one-pot dehydrogenation of cyclohexanol to cyclohexanone and subsequent Claisen–Schmidt condensation. In the reaction mixture obtained in the presence of NiAlO, CoAlO, and ZnAlO catalysts, a cyclohexyl ester of 6-hydroxyhexanoic acid was detected together with the main product. This is most likely a by-product obtained after the oxidation, ring opening, and subsequent esterification of the cyclohexanol. [ABSTRACT FROM AUTHOR]

Catalytic studies hydrogen production via steam reforming of ethanol (SRE) are essential for process optimization. Likewise, selecting the ideal support for the active phase can be critical to achieve high conversion rates during the catalytic steam reforming process. In this work, copper-based catalysts were synthesized using two different supports, NaY zeolite and Nb2O5/Al2O3 mixed oxides. The materials were prepared using wet impregnation and characterized for their physicochemical properties using different analytical techniques. Differences in the catalyst morphologies were readily attributed to the characteristics of the support. The Cu/NaY catalyst exhibited a higher specific surface area (210.40 m2 g−1) compared to the Cu/Nb2O5/Al2O3 catalyst (26.00 m2 g−1), resulting in a homogeneous metal dispersion over the support surface. The obtained results showed that, at 300 °C, both the Cu/Nb2O5/Al2O3 and Cu/NaY catalysts produced approximately 50% hydrogen and 40% acetaldehyde, but with significant differences in conversion (6% and 56%, respectively). At 450 °C, a greater product distribution and a 10% higher conversion were observed when the catalyst was supported on NaY compared to Nb2O5/Al2O3. Hence, the performance of copper-based catalysts was influenced significantly by the textural properties of the support. [ABSTRACT FROM AUTHOR]

NbVOx mixed oxides were synthesized, characterized, and evaluated as catalysts for the extractive catalytic oxidative desulfurization (ECODS) of dibenzothiophene (DBT) using acetonitrile as a solvent. The mixed oxides were prepared using two different vanadium precursors: ammonium metavanadate and vanadium(IV)-oxy acetylacetonate. These precursors influenced the acidic/basic properties and the concentration of oxygen vacancies in the resulting catalysts. The texture and surface properties of the synthesized materials were analyzed using nitrogen adsorption/desorption, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and UV–visible spectroscopy (UV-vis). Their catalytic activity was evaluated through the dehydration and dehydrogenation of 2-propanol and the ECODS of DBT. The mixed oxides synthesized with an excess of ammonium metavanadate (Nb:V = 1:2) demonstrated superior catalytic activity in removing DBT from the oil phase, achieving approximately 90% removal within 90 min at 60 °C. This enhanced activity is attributed to its higher acidity, greater concentration of oxygen vacancies, and the presence of vanadium peroxo ligands on its surface.

Single phase CuCoMgAl-layered hydroxides were obtained by making fine adjustment to their composition through changing the (Co + Cu)/Mg = 0.5; 1; 2; 3 and Co/Cu = 0.5; 1; 2 ratios. The rise of Co/Cu in systems contributed to the increase in their thermal stability. CuCoMgAl-catalysts showed high selectivity of carbonyl group hydrogenation in furfural and 5-hydroxymethylfurfural. In furfural hydrogenation, the selectivity to furfuryl alcohol was more than 99%, and in 5-hydroxymethylfurfural hydrogenation, the selectivity to 2,5-hydroxymethyl furfural was 95%. The surface of the samples with different Co/Cu after calcination and reduction was the same and had a «core-shell» structure (TEM). «Core» consisted of Cu and Co metallic particles. «Shell» consisted of CuCoMgAlOx mixed no-stoichiometric spinel oxides. There was no sintering or change in size of the metallic particles after the reaction. For the sample with Co/Cu = 1, their phase composition after reaction remained unchangeable. The increase of Co/Cu led to the formation of an X-ray amorphous phase after the reaction. This suggests the decrease in structural stability of this sample. The obtained results prove the prospects of using bimetallic CoCu-systems for hydrogenation of furan aldehydes, and opens up new directions for further research and improvement.

This work reports on the ultrasonic synthesis of layered double hydroxides (LDH), also known as hydrotalcite-type materials. We have studied the influence of ultrasonic irradiation parameters (power, time, temperature) on the physicochemical properties of Ni2Mg4Al1.8La0.2 hydrotalcite-type precursors and related mixed oxides (MO). The low-frequency acoustic cavitation (22 kHz) was applied during the precipitation and aging steps of co-precipitation synthesis and the results were compared to the classical preparation route. The materials were characterized by ATR-FTIR, XRD, N2 adsorption–desorption, SEM-EDX, S/TEM-HAADF, and XPS. Using the combination of acoustic cavitation-assisted precipitation and aging steps, XRD experiments show a higher purity hydrotalcite phase and a better incorporation of lanthanum ions into the LDH structure. As expected, morphological characterization shows a reduction in average crystallite size and an increase in surface area and pore volume, combined with a drastic reduction in synthesis time (45 min at room temperature versus 19 h at 60 °C in conventional synthesis). The insertion of a larger quantity of La is observed by S/TEM-EDSX mapping which also shows a better distribution of lanthanum atoms within the LDH and mixed oxide structures.

The hydrogen production by ethanol steam reforming over Ni–Co–Al mixed oxides derived from layered double hydroxides is evaluated in this work. The catalysts were prepared via coprecipitation and characterized through N2 adsorption and desorption measurements, X-ray diffraction (XRD), temperature programmed reduction (TPR), CO2 desorption and oxidation, and scanning electron microscopy. The catalyst activity was evaluated in a fixed bed reactor between 400 and 600 °C, using ethanol and water in a 1:3 ratio, with online analysis of products by gas chromatography. Increasing the amount of Co increased surface area. XRD analysis revealed a mixture of Ni–Al and Co-Al oxides after calcination. The TPR profiles revealed that an increase in Co content leads to a more stable mixed oxide phase. The activity results showed that H2 selectivity increases with reaction temperature and Co content in the catalyst. The high selectivity for H2 is attributed to methane decomposition being favored. Hence the larger production of carbon is promoted by the excess of Co in the catalyst with the highest amount of Co. The decomposition of ethanol producing CO, CH4, and H2 is favored at higher temperatures. The selectivity for H2 remained above 90% in long term tests at 600 °C. XRD analysis after reactions showed that the presence of Co decreases the sintering of catalysts. The compromise between resistance to sintering and carbon deposition points to a medium amount of Co in the catalyst. All catalysts showed metallic phases after the reaction, demonstrating that the reduction step is not necessary for this reaction. [ABSTRACT FROM AUTHOR]

Catalysts based on CoCuMgAl mixed oxides were synthesized and studied in the hydrogenations of furfural and 5-hydroxymethylfurfural under different conditions. The changes in the structural properties of the catalysts at different stages of their preparation were studied using a set of physical methods (XRD, SEM, and TEM). It was shown that the fine regulation of the chemical compositions of the mixed oxides (i.e., changes in the Co/Cu ratio) made it possible to vary the structure, morphology, and catalytic properties of the samples. The phase composition of catalysts with Co/Cu = 1 did not change during the catalytic reaction, although the initial catalysts had a less-homogeneous morphology. 5-hydroxymethylfurfural conversion was higher for the samples with Co/Cu = 1. Furfural conversion increased when raising the Co/Cu ratio. The selectivity toward furfuryl alcohol for the catalyst with Co/Cu = 2 under mild conditions of furfural hydrogenation was more than 99%. The results obtained are important for the development of the scientific foundations of the preparation of hydrogenation catalysts with a fine-tunable composition in order to obtain the desired hydrogenation products. [ABSTRACT FROM AUTHOR]

[Display omitted] • Brønsted sites generated by SiO 2 on Lewis acidic ZrO 2 , TiO 2 , Nb 2 O 5 , or Al 2 O 3. • Acid strength quantified by TMPO chemisorption 31P NMR. • Brønsted acid strength increased with MOx Lewis acidity, as Al 2 O 3 > Nb 2 O 5 > TiO 2 > ZrO 2. • Hydroalkoxylation rates maximized at near-monolayer silica loading. • Hydroalkoxylation rates scaled with Brønsted acidity. Mixed oxides are ubiquitious solid acid catalysts for a number of transformations. Here, the chemistry of mixed oxide interfaces was experimentally probed by constructing model SiO 2 on MO x interfaces using a liquid-phase, stoichiometrically-controlled deposition of tetraethyl orthosilicate (TEOS). Catalytically active Brønsted sites were generated in four series of overcoated SiO 2 on metal oxide materials prepared by depositing TEOS onto Al 2 O 3 , anatase TiO 2 , Nb 2 O 5 , and ZrO 2. Pyridine DRIFTS studies indicate that the acidity of deposited silanol groups was enhanced by interaction with the metal oxide surface, suggesting that pseudo-bridging silanol type structures were formed. Trimethylphosphine oxide (TMPO) 31P NMR experiments showed that Brønsted acid strength varied in the overcoated materials, with increasing strength in the following order: SiO 2 /ZrO 2 < SiO 2 /TiO 2 < SiO 2 /Nb 2 O 5 < SiO 2 /Al 2 O 3. This order correlated with the Lewis acidity and chemical hardness of the underlying metal oxides. The catalytic performance of the materials was evaluated in the liquid-phase hydroalkoxylation of dihydropyran with n-octanol, revealing that activity was highly dependent on SiO 2 loading, which impacted the density of acid sites, and scaled exponentially with Brønsted acid strength, determined by the core metal oxide identity. Brønsted acid strength appears to be the key driver of the materials' activity, with the highest areal rate of 2.2 mmol / m2 – h being measured over SiO 2 /Al 2 O 3. This study shows that SiO 2 -overcoated materials are a systematically tunable class of catalysts that can be applied to acid catalyzed reactions. [ABSTRACT FROM AUTHOR]

Single phase CuCoMgAl-layered hydroxides were obtained by making fine adjustment to their composition through changing the (Co + Cu)/Mg = 0.5; 1; 2; 3 and Co/Cu = 0.5; 1; 2 ratios. The rise of Co/Cu in systems contributed to the increase in their thermal stability. CuCoMgAl-catalysts showed high selectivity of carbonyl group hydrogenation in furfural and 5-hydroxymethylfurfural. In furfural hydrogenation, the selectivity to furfuryl alcohol was more than 99%, and in 5-hydroxymethylfurfural hydrogenation, the selectivity to 2,5-hydroxymethyl furfural was 95%. The surface of the samples with different Co/Cu after calcination and reduction was the same and had a «core-shell» structure (TEM). «Core» consisted of Cu and Co metallic particles. «Shell» consisted of CuCoMgAlOx mixed no-stoichiometric spinel oxides. There was no sintering or change in size of the metallic particles after the reaction. For the sample with Co/Cu = 1, their phase composition after reaction remained unchangeable. The increase of Co/Cu led to the formation of an X-ray amorphous phase after the reaction. This suggests the decrease in structural stability of this sample. The obtained results prove the prospects of using bimetallic CoCu-systems for hydrogenation of furan aldehydes, and opens up new directions for further research and improvement. [ABSTRACT FROM AUTHOR]

The increase of consciousness towards global warming and the need to reduce greenhouse gas emissions lead to the necessity of finding alternative applications based on easy-to-use materials in order to control and reduce global CO2 emissions. Layered Double Hydroxides (LDHs) and LDH-derived materials are potentially good adsorbents for CO2, thanks to their low cost, easy synthesis, high sorption capacity, and surface basicity. They have been intensively studied in CO2 capture at high temperature, presenting variable sorption capacities for MgAl LDHs with the same composition, but prepared under different synthesis conditions. The ambient temperature coprecipitation synthesis method is an attractive one-step procedure to synthesize LDHs under mild conditions, with low energy consumption and short synthesis time. The present study is based on the synthesis and characterization of hydrotalcites by a mild-conditions coprecipitation process and the production of derived mixed oxides to be used as CO2 adsorbents. A critical comparison to similar materials is reported. Moreover, the effect of the surface basicity of the derived mixed oxides (measured by adsorption calorimetry) and the CO2 sorption capacity are discussed, showing a linear correlation between the amount of weak and very strong basic sites and the CO2 adsorption behavior. [ABSTRACT FROM AUTHOR]

A rational synthetic approach is introduced to enable hydrogen insertion into oxides by forming a solid solution of a reducible oxide with a less reducible oxide as exemplified with RuO2 and TiO2 (Ru_x, a mixture of x% RuO2 with (100−x)% TiO2). Hydrogen exposure at 250 °C to Ru_x (Ru_x_250R) results in substantial hydrogen incorporation accompanied by lattice strain that in turn induces pronounced activity variations. Here, we demonstrate that hydrogen incorporation in mixed oxides promotes the oxidation catalysis of propane combustion with Ru_60_250R being the catalytically most active catalyst. [ABSTRACT FROM AUTHOR]

CeO2-TiO2 is an important mixed oxide due to its catalytic properties, particularly in heterogeneous photocatalysis. This study presents a straightforward method to obtain 1D TiO2 nanostructures decorated with CeO2 nanoparticles at the surface. As the precursor, we used H2Ti3O7 nanoribbons prepared from sodium titanate nanoribbons by ion exchange. Two cerium sources with an oxidation state of +3 and +4 were used to obtain mixed oxides. HAADF–STEM mapping of the Ce4+-modified nanoribbons revealed a thin continuous layer at the surface of the H2Ti3O7 nanoribbons, while Ce3+ cerium ions intercalated partially between the titanate layers. The phase composition and morphology changes were monitored during calcination between 620 °C and 960 °C. Thermal treatment led to the formation of CeO2 nanoparticles on the surface of the TiO2 nanoribbons, whose size increased with the calcination temperature. The use of Ce4+ raised the temperature required for converting H2Ti3O7 to TiO2-B by approximately 200 °C, and the temperature for the formation of anatase. For the Ce3+ batch, the presence of cerium inhibited the conversion to rutile. Analysis of cerium oxidation states revealed the existence of both +4 and +3 in all calcined samples, regardless of the initial cerium oxidation state. [ABSTRACT FROM AUTHOR]

Ni(Mg)Al-layered hydroxides with molar ratios of (Ni + Mg)/Al = 2, 3, 4 and Ni/(Ni + Mg) = 0.1, 0.3, 0.5, 0.7 were synthesized by mechanochemical activation. It has been proven that the phase composition of the samples was presented by a single hydrotalcite phase up to Ni/(Ni + Mg) = 0.5. For the first time, catalysts based on Ni(Mg)Al-layered hydroxides prepared by a mechanochemical route have been studied in the reaction of furfural hydrogenation. The correlation between furfural conversion, the selectivity of the products, and the composition of the catalysts was established. The effect of phase composition, surface morphology, and microstructure on the activity of the catalysts was shown by XRD, SEM, and TEM. It was found that catalysts with Ni/(Ni + Mg) = 0.5 have the highest furfural conversion. Herewith, the product selectivity can be regulated by the (Ni + Mg)/Al ratio. [ABSTRACT FROM AUTHOR]

Samples of La1-3xLixM2xCoO3-δ (M = Ca, Sr, Ba; 0≤x≤0,1) were synthesized by co-precipitation method. It is shown that the region of their homogeneity lies in the range of substitutions 0≤ x ≤0.05. The volume of the unit cell increases with the size of the alkaline earth metal that replaces lanthanum. Surface morphology of the obtained mixed oxides was studied by SEM. In all samples (except strontium - containing) paramagnetic Co2+ ions from the impurity Co3O4, which are in different local environments and have different degrees of exchange interaction with each other, are contained in the form of chain fragments -Co2+-O2--Co2+-O2--Co2+-O2— and contain defective centers Со2+, which are formed during the desorption of lattice oxygen from the surface, or in the process of diffusion of oxygen from the volume of material to the surface. In strontium-containing samples La0,85Lix0,05Sr0,01CoO3-δ there are mainly ferromagnetic clusters Co3+-Co4+.

Proton exchange membrane (PEM) water electrolysis represents a promising technology for green hydrogen production, but its widespread deployment is greatly hindered by the indispensable usage of platinum group metal catalysts, especially iridium (Ir) based materials for the energy-demanding oxygen evolution reaction (OER). Herein, we report a new sequential precipitation approach to the synthesis of mixed Ir-nickel (Ni) oxy-hydroxide supported on antimony-doped tin oxide (ATO) nanoparticles (IrNi _y O _x /ATO, 20 wt.% (Ir + Ni), y = 0, 1, 2, and 3), aiming to reduce the utilisation of scarce and precious Ir while maintaining its good acidic OER performance. When tested in strongly acidic electrolyte (0.1 M HClO _4 ), the optimised IrNi _1 O _x /ATO shows a mass activity of 1.0 mA µ g _Ir ^−1 and a large turnover frequency of 123 s ^−1 at an overpotential of 350 mV, as well as a comparatively small Tafel slope of 50 mV dec ^−1 , better than the IrO _x /ATO control, particularly with a markedly reduced Ir loading of only 19.7 µ g _Ir cm ^−2 . Importantly, IrNi _1 O _x /ATO also exhibits substantially better catalytic stability than other reference catalysts, able to continuously catalyse acidic OER at 10 mA cm ^−2 for 15 h without obvious degradation. Our in-situ synchrotron-based x-ray absorption spectroscopy confirmed that the Ir ^3+ /Ir ^4+ species are the active sites for the acidic OER. Furthermore, the performance of IrNi _1 O _x /ATO was also preliminarily evaluated in a membrane electrode assembly, which shows better activity and stability than other reference catalysts. The IrNi _1 O _x /ATO reported in this work is a promising alternative to commercial IrO _2 based catalysts for PEM electrolysis.

In this study, we prepared Al _2 O _3 -TiO _2 (AT) mixed oxides to synthesize NiW catalysts for sulfur removal reactions. The AT support samples were prepared with various surfactants. Additionally, gallium atoms (2.4 wt%) were introduced as an additive to coat the outer surface layers of AT support that lacked Al ^3+ or Ti ^2+ cations. Characterization results showed substantial differences in textural properties, chemical composition, and surface acidity. The x-ray Photoelectron Spectroscopy (XPS) and High-Resolution Transmission Electron Microscopy (HR-TEM) results demonstrated that the NiW/AT-L-Ga sample has a better combination of dispersion, sulfidation, and promotion among materials. The sulfided NiW/AT-L-Ga catalyst had the highest catalytic activity. After incorporating Ga, XPS observed that the activity could be associated with an increase in the NiWS active phase; however, including a surfactant in the synthesis of the support allowed an increase in the amount of NiWS phase. The active phase was modeled considering the HR-TEM results for the slab length, revealing the atoms at the border susceptible to promotion.

Recently, catalysts with hydrotalcites and hydrotalcite-derived compounds have attracted particular interest due to their specific properties, mostly well-developed texture, high thermal stability, and favorable acid–base properties. In this work, we report the investigation of ammonia synthesis on barium-promoted cobalt catalysts supported on hydrotalcite-derived Mg-Al mixed oxides with different Mg/Al molar ratios. The obtained catalysts were characterized using TGA-MS, nitrogen physisorption, XRPD, TEM, STEM-EDX, H2-TPD, CO2-TPD, and tested in ammonia synthesis (470 °C, 6.3 MPa, H2/N2 = 3). The studies revealed that the prepared Mg-Al mixed oxides are good candidates as support materials for Co-based catalysts. However, interestingly, the support composition does not influence the activity of Ba/Co/Mg-Al catalysts. The change in Mg/Al molar ratio in the range of 2–5 did not significantly change the catalyst properties. All the catalysts are characterized by similar textural, structural, and chemisorption properties. The similar density of basic sites on the surface of the studied catalysts was reflected in their comparable performance in ammonia synthesis.

We report the preparation by three methods (coprecipitation, self-combustion, and microwave-assisted self-combustion) of Pr-promoted Ni-catalysts for H2/CO>1 syngas production by dry reforming of methane (DRM). The catalysts were characterized by a package of techniques to describe their physicochemical properties including several techniques using CO2 as a probe molecule. The catalysts were tested at 600 °C (10 h) and 120 L∙g−1 h−1, without previous H2-reduction. The coprecipitation method allowed obtaining a catalyst with a higher surface area and CO2 capture capacity (3.1 mg∙gcat−1), a higher number of basic sites, lower average Ni0 particle size (5.5 nm), higher catalytic conversions (48–65% of CH4 and 39–42% of CO2) and H2 (H2/CO = 1.15–1.75) yield but higher C formation. In addition, the catalyst obtained by microwave-assisted self-combustion presented better performance (45–51% of CH4 and 35–38% of CO2) than traditional self-combustion (40–45% of CH4 and 33–35% of CO2). The results showed that not only Ni0 particle size but also the presence of basic sites with high thermal stability and grain morphology affect the catalytic activity and coke formation.

Anodic oxides were grown to 50 V on Ta-Nb sputtering deposited alloys, with high Nb content, in acetate ions containing an aqueous solution to study the effect of the anodizing bath composition on anodic layers' dielectric properties. Photoelectrochemical measurements proved the presence of a photocurrent in the band gap of photon energy lower than oxides, due to optical transitions involving localized electronic states as a consequence of acetate ions incorporation. Flat band potential value estimates assessed the insulating nature of the anodic oxides grown in the acetate buffer solution. Differential capacitance measurements showed that the highest capacitance value was measured for the sample grown on Ta-66%Nb. This capacitance value was higher with respect to those estimated for pure Ta and pure Nb anodic layers and with respect to the same alloy anodized in NaOH solution, i.e., acetate-free anodizing bath. [ABSTRACT FROM AUTHOR]

Mixed Ni-Al oxide catalytic precursors with different elemental ratios (20, 50, and 80 wt.% Ni0) were synthesized using green supercritical antisolvent co-precipitation (SAS). The obtained oxide precursors and metal catalysts were characterized in detail by X-ray diffraction (XRD) analysis, atomic pair distribution function (PDF) analysis, CO adsorption, and high-resolution transmission electron microscopy (HRTEM). It was found that the composition and structure of the Ni-Al precursors are related to the Ni content. The mixed Ni1−xAlxO oxide with NiO-based crystal structure was formed in the Ni-enriched sample, whereas the highly dispersed NiAl2O4 spinel was observed in the Al-enriched sample. The obtained metal catalysts were tested in the process of anisole H2-free hydrogenation. 2-PrOH was used as a hydrogen donor. The catalyst with 50 wt.% Ni0 demonstrated the highest activity in the hydrogenation process. [ABSTRACT FROM AUTHOR]

Copper was incorporated into the Ce-Sn and comparative Ce-Zr oxide supports by one-pot precipitation in the presence of CTAB template and by the impregnation of templated Ce-Sn and Ce-Zr oxides. The synthesized Cu-Ce-Sn and Cu-Ce-Zr catalysts were tested in the continuous-flow preferential oxidation of CO in hydrogen excess. The one-pot synthesized tin- and zirconium-doped catalysts demonstrated better CO conversion and CO2 selectivity than their impregnated counterparts. For the tin-modified ternary system that showed the best catalytic performance, the copper content was further optimized. The structure, reducibility, surface chemical state and textural properties of the catalysts were analyzed by SEM-EDX, XRD, H2-TPR, Raman spectroscopy, XPS and TEM. The nonmonotonic changes in the specific surface area, Cu+/Cu2+ ratio and ratio of lattice and non-lattice oxygen with increasing the Cu content are discussed in terms of copper distribution in the catalysts. The influence of the interaction between copper oxide species and the cerium–tin/cerium–zirconium oxide support on the performance of the ternary catalysts was thoroughly analyzed and discussed. [ABSTRACT FROM AUTHOR]

Mixed Ta2O5 – TiO2 binary system was studied by a combination of differential thermal analysis (DTA), scanning electron microscopy-energy dispersive spectrometry (SEM-EDS), X-ray diffraction (XRD) and in situ high temperature X-ray diffraction (HT-XRD) techniques. Different compositions of the mixed oxide powders were fabricated by ball–milling the powdered compositions, pelletizing the homogenized composite powders, and heating the green pellets in air at different temperatures for fixed time intervals. The sintered pellets were evaluated and characterized with respect to porosity, morphology, and phase distribution. DTA runs of the un-sintered powders indicated the onset temperatures for both exothermic and endothermic changes in the binary system. Significant amount of sintering was observed to take place at temperatures higher than 900 °C. Both room and high temperature X-ray diffraction patterns exhibited consistency in phase formation. A ternary compound (TaTiO4) and a ternary solid solution (Ti0.33Ta0.67O2) were observed to form in both room and high temperatures in addition to the respective binary phases (Ta2O5 and TiO2). A sintering temperature in the range 900–1000 °C was observed to be adequate to achieve the requisite mechanical strength and optimum internal porosity (40–48%) for subsequent electrochemical polarization experiments.

A series of clinoptilolite-supported catalysts, modified with hydrotalcite-like phase (HT) by co-precipitation, were prepared and tested in NH3-SCR reactions. It was found that deposition of HT on clinoptilolite increased conversion of NO within 250–450 °C, and that the positive impact on the catalytic activity was independent of HT loading. The promoting effect of clinoptilolite was attributed to Brönsted acid sites present in the zeolite, which facilitated adsorption and accumulation of ammonia during the catalytic process. Concentration of N2O in the post-reaction gas mixture reached its maximum at 300 °C and the by-product was most likely formed as a consequence of NH4NO3 decomposition or side reaction of NH3 oxidation in the high-temperature region. The gradual elimination of nitrous oxide, noticed as the material with the highest concentration of hydrotalcite phase, was attributed to the abundance of oligomeric iron species and the superior textural parameters of the material. UV-Vis experiments performed on the calcined samples indicated that Fe sites of higher nuclearity were generated by thermal decomposition of the hydrotalcite phase during the catalytic reaction. Therefore, calcination of the materials prior to the catalytic tests was not required to obtain satisfactory overall catalytic performance in NO reductions. [ABSTRACT FROM AUTHOR]

In this study, ternary mixed oxide catalysts containing Al2O3-MoO3-MgO and Al2O3-MoO3-WO3 were prepared with a changing ratio of MoO3:Al2O3 between 0.05 and 20.00. All catalysts showed 100% selectivity towards propene during the conversion of propan-2-ol at temperatures between 220 and 400 °C. The catalysts prepared from WO3 possessed very strong acid sites, which cause higher catalytic activity than catalysts prepared from MgO. Besides, the ratio of MoO3:Al2O3 was found to be directly proportional to the conversion yield for all catalysts. XRD results show that whole MgO reacted with Al2O3 and MoO3 to form amorphous MgMoO4 and MgAl2O4 phases during catalyst preparation. Furthermore, WO3 reacted only with Al2O3 to form Al2(WO4)3 and WO3 phase was also detected in the final product. The higher surface acidity and catalytic activity of Al2O3-MoO3-WO3 catalyst referred to this WO3 phase within the structure. [ABSTRACT FROM AUTHOR]

Abstract We report on the facile synthesis of SiO2@nitrized‐TiO2 nanocomposite (NST) by calcination of TiO2 xerogel with OctaAmmonium POSS® (N‐POSS; POSS=polyhedral oligomeric silsesquioxanes). The as‐obtained nanoporous mixed oxide is constituted by uniformly distributed SiO2 and nitrized‐TiO2, where the silica component is present in an amorphous state and TiO2 in an anatase/rutile mixed phase (92.1 % vs. 7.9 %, respectively) with very small anatase crystallites (3.7 nm). The TiO2 lattice is nitrized both at interstitial and substitutional positions. NST features a negatively charged surface with a remarkable surface area (406 m2 g−1), endowed with special adsorption capabilities towards cationic dyes. Its photocatalytic behavior was tested by following the degradation of standard aqueous methylene blue and methyl orange solutions under UV and visible light irradiation, according to ISO 10678:2010. For comparison, analogous investigations were carried out on a silica‐free N−TiO2, obtained by using NH4Cl as nitrogen source.

The glycerol generated as a by-product in the production of biodiesel could be used as a renewable raw material to economically promote the production process. The catalytic conversion of glycerol to a product with higher added value, such as glycerol carbonate, has attracted great interest in the chemical, pharmaceutical, and lithium battery industries, among others, due to its low toxicity, hydration capacity, and biodegradability. Layered-double hydroxide (LDH) materials, the precursors of the catalysts, were synthesized by a direct coprecipitation method to incorporate a third metal ion in addition to magnesium and aluminum ions. This method is the easiest regularly applied technique to design these low cost anionic nanoclay. The atomic percentage of Cu, Zn, or Ni incorporated was 15% of the Mg load in the material. The synthesis atomic ratio, (M2++Mg2+)/Al3+ had a constant value of 3, where M represents the transition metal incorporated. LDHs produced the corresponding mixed metal oxides by thermal decomposition. These materials have excellent properties for reactions catalyzed by the basic sites, high surface area, homogeneous cation dispersion, and thermal stability. The physicochemical material properties were characterized by XRD, N2 sorption, MP-AES, TPD-CO2, SEM, and XPS. The mixed oxides were evaluated in the catalytic conversion of glycerol to glycerol carbonate. The addition of Cu, Ni, or Zn to the matrix of Mg and Al produced changes in its physicochemical properties and mostly in the catalytic activity. X-ray diffractograms of LDHs showed the typical characteristic structure of layers even with metallic ions of Cu, Ni, or Zn incorporated, because their ionic radii are similar to that of the Mg ion, 0.69, 0.73, and 0.74 Å, respectively. The obtained mixed oxides showed a high catalytic activity towards the conversion of glycerol to glycerol carbonate under mild reaction conditions, a 1:2 ratio of glycerol:ethylene carbonate and solvent free. Relative yields higher than 80% were obtained, attributable to an adequate distribution of basicity and textural parameters. The catalysts were used in successive reaction cycles without significant loss of activity.

New ternary materials TiO2-Al2O3-GnPs (TAG) were prepared by using an innocuous sol-gel method with a slight modification for the addition of graphene nanoplatelets (GnPs), under room temperature and atmospheric pressure. The materials TiO2-Al2O3-GnPs were prepared with variations of concentration between 0.05 and 1 wt % of GnPs. In this study, we analyzed the physicochemical properties by X-ray diffraction (XRD) and UV-Vis spectroscopy, textural properties by N2 physisorption, morphology by scanning and transmission electron microscopy (SEM, TEM) and a chemical species analysis was carried out by X-ray photoelectron spectroscopic (XPS). The photocatalytic activity of each material was evaluated in the degradation of a model molecule, Diuron, a carcinogenic and cytotoxic herbicide used in farm fields. To determine reaction selectivity and mineralization degree, the photocatalytic reaction was monitored by using UV-Vis spectroscopy and total organic carbon (TOC). In samples with higher GnPs’ concentration, a good enough specific surface area of up to 379 m2/g was observed, and reduced band gap energy (2.8 eV) with respect to TiO2 and mixed oxide (3.2 and 3.1 eV respectively), was obtained. These resulting properties were the key indicator so that the materials could be applied as photocatalysts. In the photocatalytic activity determination, TAG-0.75 was the sample that showed the best results with respect to the mixed oxide; the highest photocatalytic conversion, the reduced average life time, and increased mineralization and reaction selectivity.

In this study, V2O5/ZrO2 samples loaded with different wt% of V2O5, ranging between 0% and 20% (wt% = 2.5, 3.6, 7.5, 10, and 20), were prepared and studied in the dehydrogenation of 2-butanol in order to investigate their acid-basic properties and to select the most interesting sample, that was identified in the 3.6 wt%V2O5/ZrO2. Such a catalyst was modified by adding phosphate at different atomic ratios (P/V = 0.5, 1, and 2) and further characterized by XRD, SEM-EDX, ESR, UV-Vis-PIR diffuse reflectance. Tests of catalytic dehydrogenation of 2-butanol were also performed. Then, the so-prepared samples were investigated in the oxidative dehydrogenation (ODH) of propane that represents the reaction of main interest in this study. It has been shown that the introduction of 3.6 wt%V2O5 and phosphate in the zirconia matrix enhances the stability of the tetragonal structure, improves acidity, and promotes ODH activity. Compared to the unpromoted 3.6 wt%V2O5/ZrO2 catalyst, the addition of phosphate increases the overall propane conversion from 12% to 20%, and also the propylene selectivity from 54% to near 64%, in the experimental conditions F °C3H8/F°O2/F°total (cm3/min): 3.6/1.8/60 at the temperature of 500 °C. The influence of the reaction mixture on the ODH, in particular the oxygen flow rate, was addressed. Highlights: Phosphorus loaded V2O5/ZrO2 catalysts were prepared and investigated in the oxidative dehydrogenation of propane. Addition of V2O5 and phosphorus to ZrO2 stabilized the tetragonal phase with respect to the monoclinic one. Among the prepared V2O5/ZrO2 samples, the most active catalyst corresponds to 3.6 wt% of V2O5/ ZrO2, The addition of phosphorus to 3.6 wt% V2O5/ZrO2 improves acidity and selectivity to propylene. Correlation between catalysts acidity and oxidative dehydrogenation of propane was observed. [ABSTRACT FROM AUTHOR]

Silica, titania, and mixed silica–titania powders have been used as supports for loading 5 wt% Cu, 5 wt% Ag, and 2.5 wt% Cu-2.5 wt% Ag with the aim of providing a series of nanomaterials with antifouling properties. All the solids were easily prepared by the wetness-impregnation method from commercially available chemical precursors. The resulting materials were characterized by several techniques such as X-ray diffraction analysis, X-ray photoelectron spectroscopy, N2 physisorption, and temperature-programmed reduction measurements. Four selected Cu and Ag SiO2- and TiO2-supported powders were tested as fillers for the preparation of marine antifouling coatings and complex viscosity measurements. Titania-based coatings showed better adhesion than silica-based coatings and the commercial topcoat. The addition of fillers enhances the resin viscosity, suggesting better workability of titania-based coatings than silica-based ones. The ecotoxicological performance of the powders was evaluated by Microtox luminescence tests, using the marine luminescent bacterium Vibrio fisheri. Further investigations of the microbiological activity of such materials were carried out focusing on the bacterial growth of Pseudoalteromonas sp., Alteromonas sp., and Pseudomonas sp. through measurements of optical density at 600 nm (OD600nm). [ABSTRACT FROM AUTHOR]

Bio-oil derived from the pyrolysis of lignocellulosic biomass residues cannot be used directly as biofuel due to the high content of oxygenated compounds. As an alternative, bio-oil must undergo a deoxygenation process, such as catalytic hydrodeoxygenation (HDO). In this sense, this work studied the effect of different concentrations of Ce3+ and Ce4+ in layered double hydroxides (LDHs) in order to obtain mixed oxide catalysts containing NiAlCe (NiO-NiAl 2 O 4 -CeO 2) with low cost and high performance for the hydrodeoxygenation of anisole as a model bio-oil compound. Mixed oxides were obtained from the thermal decomposition of layered double hydroxides (LDHs) by using terephthalic acid as compensation anion, with molar ratio: Ni2+/(Al3++ M) = 1.0, where M = Ce3+; Ce4+ or Ce3+-Ce4+; and Al/Ce ratios of 9 and 1. Characterization analyses confirmed the formation of LDHs for all materials, although at lower Al/Ce ratio it is observed a loss of crystallinity, due to a greater repulsion and distortion of the layer structure caused by the incorporation, in greater amount, of cations with a high ionic radius. The increase in the content of cerium in mixed oxides also led to an increase in the acidity of the catalysts, in addition to a reduction in the surface area, justified by the pore blockage by CeO 2 on the catalyst surface. The greater structural and thermal stability was evidenced in the LDHs derived from Ce4+, as well as a greater dispersion of the NiO phase in the corresponding mixed oxides, and therefore presenting greater anisole conversion. The obtained data indicated that the presence of Ce4+ ions on the catalyst surface was decisive in the conversion of anisole to cyclohexane, the main deoxygenated product, obtained via the direct deoxygenation and hydrogenation mechanism. [Display omitted] • Mixed oxide (NiAlCe) prepared from layered double hydroxides (LDHs) are effective catalysts in HDO reactions. • Cerium oxidation state used during synthesis determined the textural properties as well as the catalytic activity. • Catalyst prepared from Ce4+ were more active and stable catalyst. • LDH stability and active phase dispersion explain the catalytic behaviour. [ABSTRACT FROM AUTHOR]

The Phase, microstructural and dielectric properties of Ba1-xSrxTi4O9 (0 ≤ x ≤ 0.8) ceramics were investigated. The XRD analysis revealed the formation of orthorhombic structured (Pnmm) BaTi4O9 phase. The XRD peaks were observed to shift towards the lower 2θ values with increasing Sr2+ contents which may be attributed to the substitution of relatively larger cation of Sr2+ (RSr = 1.61 Å) for Ba2+ (RBa = 1.44 Å) in BaTi4O9. The dielectric constant (εr) increased with Sr2+ substitution from 22 to 122 at 1MHz. The maximum value of the dielectric loss was observed 0.11922 for x = 0.8 at 1 MHz. [ABSTRACT FROM AUTHOR]

The physicochemical and catalytic properties of low-cost metal mixed oxide catalysts have been researched and characterized. To explore catalysts, various characterization techniques such as BET and X-ray diffraction (XRD) have been utilized. Three distinct catalysts, C1(NiO-Co3O4/Silica), C2(NiO- Co3O4-ZnO/ Silica), and C3(NiO- Co3O4-BaO/ Silica), are synthesized with 20 wt% mixed oxide (NiO- Co3O4) supported on silica and doped with zinc/barium oxide, and then dried at 110°C overnight and calcined at 350°C All three catalysts have been tested in an ethyl acetate saponification reaction, and the conversion of reactants is calculated. In comparison to the other catalysts, C2 (NiO-Co3O4-ZnO/ Silica), which is a combination of NiO-Co3O4/SiO2 doped with zinc oxide, show good catalytic activity. In terms of catalyst doping, the addition of zinc oxide to the Silica supported original composition boosted the catalytic activity for the saponification reaction compared to barium oxide and without doped. [ABSTRACT FROM AUTHOR]

Reactive flash sintering (RFS) is a method that was recently developed to produce dense single‐phase bulk ceramic parts through solid‐state reactions in a single‐step that only takes a few minutes. The influence of the RFS parameters on the phase purity of a simple mixed oxide, (Zr0.8,Ce0.2)O2, was investigated. Parameters such as furnace temperature, furnace atmosphere, electric current density, and alternating current (AC) or direct current (DC) were examined. It was found that (Zr0.8,Ce0.2)O2 pellets with high densities, above 90% of its theoretical density, can be produced by RFS in a few minutes when RFS occurs under oxidizing atmospheres, AC fields with current densities of 100 mA·mm−2, and at a furnace temperature of 1200°C. Reducing conditions such as Ar‐H2 atmosphere and DC fields, low furnace temperatures, and low current densities resulted in phase impurities and poor reactions between the ZrO2 and the CeO2 powders. These results show that RFS is a useful method to produce mixed oxides, but it is very sensitive to the processing parameters. This is the first time that the influence of most of the RFS processing parameters has been studied systematically. Thus, the present work aims to provide guidelines on selecting the right processing parameters when exploring RFS. [ABSTRACT FROM AUTHOR]

Reactive flash sintering (RFS) is a method that was recently developed to produce dense single‐phase bulk ceramic parts through solid‐state reactions in a single‐step that only takes a few minutes. The influence of the RFS parameters on the phase purity of a simple mixed oxide, (Zr0.8,Ce0.2)O2, was investigated. Parameters such as furnace temperature, furnace atmosphere, electric current density, and alternating current (AC) or direct current (DC) were examined. It was found that (Zr0.8,Ce0.2)O2 pellets with high densities, above 90% of its theoretical density, can be produced by RFS in a few minutes when RFS occurs under oxidizing atmospheres, AC fields with current densities of 100 mA·mm−2, and at a furnace temperature of 1200°C. Reducing conditions such as Ar‐H2 atmosphere and DC fields, low furnace temperatures, and low current densities resulted in phase impurities and poor reactions between the ZrO2 and the CeO2 powders. These results show that RFS is a useful method to produce mixed oxides, but it is very sensitive to the processing parameters. This is the first time that the influence of most of the RFS processing parameters has been studied systematically. Thus, the present work aims to provide guidelines on selecting the right processing parameters when exploring RFS. [ABSTRACT FROM AUTHOR]

Recently, catalysts with hydrotalcites and hydrotalcite-derived compounds have attracted particular interest due to their specific properties, mostly well-developed texture, high thermal stability, and favorable acid–base properties. In this work, we report the investigation of ammonia synthesis on barium-promoted cobalt catalysts supported on hydrotalcite-derived Mg-Al mixed oxides with different Mg/Al molar ratios. The obtained catalysts were characterized using TGA-MS, nitrogen physisorption, XRPD, TEM, STEM-EDX, H2-TPD, CO2-TPD, and tested in ammonia synthesis (470 °C, 6.3 MPa, H2/N2 = 3). The studies revealed that the prepared Mg-Al mixed oxides are good candidates as support materials for Co-based catalysts. However, interestingly, the support composition does not influence the activity of Ba/Co/Mg-Al catalysts. The change in Mg/Al molar ratio in the range of 2–5 did not significantly change the catalyst properties. All the catalysts are characterized by similar textural, structural, and chemisorption properties. The similar density of basic sites on the surface of the studied catalysts was reflected in their comparable performance in ammonia synthesis. [ABSTRACT FROM AUTHOR]

In the present work, novel ceria-based nanocatalysts containing different quantities of La and Nd were prepared via hydrothermal synthesis. The effects of doping on the structural and physico-chemical properties of ceria were examined with several techniques, such as XRD, FESEM, TEM, Raman spectroscopy, XPS, H 2 -TPR and O 2 /NH 3 /CO 2 -TPD. The catalytic activity of doped ceria towards CO, NO and soot oxidation was evaluated in different conditions; in particular, the role of the catalyst-soot contact and the influence of NO x and water on the soot oxidation performances were investigated. La and Nd ions were well incorporated in ceria structure, but the final morphology was significantly altered. The introduction of trivalent cations was also associated with a higher abundance of defects and oxygen vacancies, but an excessive oxygen deficiency detrimentally affected the material reducibility and catalytic activity for CO and NO oxidation. Conversely, soot oxidation benefited from La and Nd addition. In particular, the Ce-La equimolar oxide exhibited outstanding performances in all the tested conditions, thanks to its optimal morphology and surface acidity. A detailed comparison with equimolar ceria-praseodymia allowed to investigate how acid-base sites and redox properties control the different catalytic mechanisms involved in standard and NO x -assisted soot oxidation. [Display omitted] • La and Nd ions can be well incorporated in the lattice of ceria-based nanocatalysts. • Excessive oxygen deficiency and defectiveness negatively affect ceria reducibility. • Equimolar ceria-lanthana shows an outstanding activity towards soot oxidation. • Acid-base sites strength is closely related to doped ceria catalytic performances. • Different NO x -assisted soot oxidation pathways are promoted by La or Pr doped ceria. [ABSTRACT FROM AUTHOR]

Mixed oxides combining d 0-and p -cations with stereoactive lone pair electrons exhibit excellent polarization abilities for potential photoelectric applications. This work reports the photochemical properties of V-doped Te–Nb mixed oxide Nb 2 Te 4 O 13 , which has the typical framework constructed by NbO 6 (d 0-) octahedra, TeO 4 , and TeO 3 (p -) polyhedra. The samples were prepared using the sol-gel method, which resulted in the final nanoparticles. The luminescence spectra, lifetimes of photoinduced electrons and holes, and conductivity properties of the samples were characterized. Nb 2 Te 4 O 13 has an indirect transition with a band energy of 2.98 eV V5+-doping shows a narrowing effect on the band gap, enhancing the harvest of the optical absorption in the visible light region. Photocatalysis tests were conducted via the photodegradation of RhB solutions under visible-light irradiation. V5+-doping depresses the intrinsic luminescence efficiency, while it significantly enhances photodegradation. It is suggested that the induced redox couples V5+/4+ and defects are responsible for the improvements of photocatalysis of Nb 2 Te 4 O 13. This work offers an effective method to modify photochemical properties via redox couples and defects induced by impurity ion doping. [ABSTRACT FROM AUTHOR]

Mesoporous hybrid materials containing inorganic and organic functional groups are relevant for advanced applications in separation, sorption or heterogeneous catalysis. The possibility of combining materials with high surface area and tailorable mesopore size with a mixed oxide framework and organic functions open the gate to imitating complex biosystems such as enzyme active sites. One of the critical aspects towards a multiscale control of these complex materials is the understanding of the actual framework structure and the interplay of the framework ions and the organic functions, and how these features are related to the sol-gel preparation conditions. In this work, mesoporous hybrid organic-inorganic thin films (MHTF) based on a mixed silica-titania matrix containing 20% aminopropyl functions were prepared and thoroughly studied by X-ray absorption spectroscopy at both the Ti and Si K-edges, and by O1s and N1s X-ray photoelectron spectroscopy. This approach permitted us to simultaneously probe the changes in Si and Ti coordination, the linkages between the inorganic centers, and the availability of the amino functions along samples with varying Si:Ti ratio. We find substantial differences between the local structure of pure inorganic oxides and the hybrid materials. In the oxides, increasing the %Ti leads to an increase in octahedral Si sites and Ti-oxo clusters with shorter Ti-O bonds. In the hybrid materials, higher Ti coordination with longer bonds are observed, along with a prevalence of Si centers with distorted tetrahedral coordination. These findings suggest that aminopropyl building blocks act as a compatibilizer between Ti(IV) and Si(IV) centers, leading to a hybrid mixed phase with large silica-titania interface. This intermixing also influences the exposition of amino groups at the pore surface. These aspects are of importance in the design of high surface area adsorbents, permselective membranes or heterogeneous catalysts. Highlights: Highly organized mesoporous thin films with aminopropyl groups and Si-Ti framework are synthesized from a one-pot, low-temperature method. We present an exhaustive spectroscopic study of these materials by combining XANES and XPS. Ti and Si K-Edge XANES permit to assess the changes in bonding and coordination of both cations in mixed oxide and hybrid matrices. XPS measurements permit to understand the formation of Si-O-Ti interfaces and the availability of the amino groups. This study permits to link sol-gel processing conditions to the structure of complex hybrid mesoporous materials. [ABSTRACT FROM AUTHOR]

The Mn-containing mixed-oxide-supported bismuth oxychloride (BiOCl) catalysts were prepared by calcining their corresponding parent hydrotalcite supported BiOCl. The crystal structure of BiOCl was found to be intact during calcination, while significant differences appeared in the chemical state of Mn and the redox capacities of the catalysts before and after calcination. Compared to the hydrotalcite-supported catalysts, the mixed-oxide-supported BiOCl showed much higher catalytic performance in the oxidation removal of formaldehyde due to the synergetic catalysis of more surface oxygen vacancies and higher surface basicity. The complete removal of formaldehyde could be achieved at 70 °C, and the removal efficiency was maintained more than 90% for 21 h. A possible reaction mechanism was also proposed. [ABSTRACT FROM AUTHOR]

The results of theoretical and experimental studies of surface properties of nanostructured films based on tin dioxide using Fourier-transform infrared spectroscopy, ellipsometry and the indicator method of the distribution of adsorption centers are presented. Etching in inductively coupled plasma was used for additional post-processing of nanostructured films in order to activate the adsorption centers.

Mixed oxides based on Mg-Al, Mg-Fe, Zn-Al, and Ni-Mg-Al were prepared, characterized and used as sorption materials for different types of active pharmaceutical ingredients (APIs)– nicotinic acid, salicylic acid, ibuprofen, paracetamol and ascorbic acid. Immobilization of APIs on solid supports was confirmed using X-Ray diffraction and infrared spectroscopy. Overall, the best sorption material for mentioned substances showed to be mixed Mg-Al oxides (>80 % of immobilized substance after 4 h except ascorbic acid). On the other hand, Mg-Fe and Mg-Ni-Al materials did not possess high sorption capacity (max. 59 % after 4 h). From studied substances, the immobilization amount was the lowest in the case of ascorbic acid (max. 44 % immobilized after 4 h), the highest amount was immobilized in the case of salicylic and nicotinic acids (>95 %, 4 h). The discussion regarding the structure of substances and properties of sorption materials is also offered.

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[Display omitted] • Acidity of the samples was in the opposite order of cation size: NiLi > NiNa > NiK. • NiLi presents the higher reduction temperature of mixed oxides. • NiLi presents the smaller Ni0 crystallite size after reduction. • The NiLi catalyst shows the highest resistance to sintering in biogas dry reforming. In this work, Ni-M-Al (M = K, Na, and Li) LDH-derived catalysts were evaluated for the biogas dry reforming. The catalysts were prepared by co-precipitation and characterized by S BET , XRD, TPR, NH 3 -TPD, CO 2 -TPD, SEM and TPO. Reactions were carried out in a fixed bed reactor with online GC analysis in step-wise mode in the range of 500–750 °C and the stability tests were performed at 700 °C. All prepared samples exhibited hydrotalcite-type structure. Differences in reducibility and in the acidity of oxides were observed. The acidity of the catalyst was in the order: NiLi > NiNa > NiK, which is in the opposite order of monovalent cation size. The NiLi catalyst showed the highest resistance to sintering during the reactions due to the higher reduction temperature of mixed oxides (Ni 2 AlO 4 and NiAl 2 O 4) which results in smaller Ni° crystallite size after reduction. The results at 700 °C showed that NiLi catalyst deactivation occurs mainly by carbon deposition, whereas the deactivation of NiK and NiNa catalyst occurs mainly by sintering. TPO results indicated different carbon species produced depending on how the reaction is performed. All the catalysts produced carbon nanotubes at 700 °C. [ABSTRACT FROM AUTHOR]