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A facile and original approach based on a one-pot non-aqueous sol–gel solvothermal process was developed to synthesize 2D Tungsten trioxide (WO3) nanoplatelets with an average size ranging from 30 to 50 nm, and a correspondingly high surface area. The structural, morphological, functional group, optical properties of the materials, and the properties of the adsorption surfaces were all investigated; the degree of surface hydroxyls (–OH groups) has been examined. Nuclear Magnetic Resonance Spectroscopy techniques indicated the formation of di-hexyl ether as a result of the solvothermal reaction. The optical absorption, measured using UV–Vis Diffuse Reflectance Spectroscopy, revealed a narrow bandgap (Eg = 2.18 and 2.48 eV for WO3-24 and WO3-48, respectively) compared to that of for bulk WO3 (2.7 eV), attributable to oxygen vacancies. The as-prepared WO3 nanoplatelets displayed excellent photocatalytic performance for degrading Rhodamine B under visible light-emitting diode light with up 99% degradation rate that was achieved in 120 min. Thus, the enhanced Rhodamine B photodegradation in the presence of WO3-24 along with H2O2 was assigned to the reactive oxygen species such as ·OH and RhB*+, involving in the strong synergistic effect between WO3 and H2O2, effectively separating of photocarriers and, as a consequence, boosting the photocatalytic efficiency. [ABSTRACT FROM AUTHOR]

Graphitic carbon nitride (g-C3N4), possessing high thermal and chemical stability, non-toxicity, facile synthesis, and low band gap energy is a promising candidate for photocatalytic applications. In this study, bulk and exfoliated g-C3N4 were synthesised from different precursors (melamine and urea). Moreover, the surface of bulk g-C3N4 and exfoliated g-C3N4 was modified with graphene (0.5 wt% and 1 wt%) aiming to obtain a prolonged carrier lifetime. The effect of g-C3N4 synthesis from various precursors and the influence of graphene content on the photocatalytic activity during the degradation of a water–methanol mixture under UVC irradiation were examined, in comparison to commercial P25. Hydrogen, methane and carbon monoxide were the decomposition products; hydrogen was the main product of decomposition, whereas CH4 and CO resulting from the reduction of CO2 were generated in a significantly smaller amount. All the produced photocatalysts, whether pure or modified with graphene, exhibited higher activity than the commercial photocatalyst P25. [ABSTRACT FROM AUTHOR]

[Display omitted] • Graphene nanoplatelets were included into the TiO 2 /WO 3 system. • Examined in the removal of gaseous benzene, and generation of H 2. • Position of the conduction bands played indeed a key-role. • Specimen with 15 mol% WO 3 and 1 wt% graphene – a five-fold increase in yield. Clean energy, as well as air and water pollution, have emerged as significant challenges in today's society. Photocatalysis offers a potential solution to address these issues. It is an advanced oxidation process that utilises light to activate a semiconductor. Among photocatalytically active materials, titanium dioxide (TiO 2) semiconductors are widely recognised. However, the performance of TiO 2 is hindered by its wide band gap (∼3.2 eV) and high recombination rate of photo-generated electron-hole (e−−h+) pairs. To overcome these limitations, TiO 2 in heterojunction with tungsten trioxide (WO3) has gained substantial attention for various photocatalytic applications. However, the literature reports contradictory behaviours due to variations in synthesis techniques and photocatalytic applications. In this study, we extensively investigated the photocatalytic properties of the TiO 2 /WO 3 system for the removal of gaseous benzene, and H 2 generation. To enhance the transport and lifetime of photo-generated excitons, graphene nanoplatelets were incorporated into the TiO 2 /WO 3 system. We examined several parameters that influenced the photocatalytic activity of the synthesised materials, including the WO 3 to TiO 2 ratio, the presence of graphene, and the specific photocatalytic application. Interestingly, the position of the conduction bands played a crucial role in hydrogen generation. The TiO 2 /WO 3 system exhibited a type-II heterojunction. While the hybridisation of TiO 2 with WO 3 was found to be detrimental to light-induced benzene removal and H 2 generation, the modification of TiO 2 /WO 3 with graphene nanoplatelets significantly improved the photocatalytic hydrogen generation. Notably, the specimen with 15 mol% WO 3 and 1 wt% graphene demonstrated a five-fold increase in yield compared to its counterpart without graphene. These findings provide valuable insights for data-driven catalysis research. [ABSTRACT FROM AUTHOR]

A new and original method, based on a non-aqueous sol–gel process, has been successfully established to produce quasi-spherical monodispersed TiO 2 nanoparticles (NPs) and also noble metals (NM) @TiO 2 heterostructures (NM = Au, Pt, Ag, 2 wt%), in one-pot and at low temperature. This has been achieved by using titanium oxyacetylacetonate as new single source precursors. This system has been deeply investigated by advanced characterization techniques. By using NMR, we have demonstrated the relatively complex mechanism behind this apparently simple synthesis, mediated by the reaction of the solvent and generated species, with many separate organic and organometallic molecules identified as being involved in the mechanism. The morphology and structure of the NM@TiO 2 heterostructures were investigated by advanced scanning transmission electron microscopy while the chemical state of the noble metal nanoparticles was check by X-ray photoelectron spectroscopy (XPS). Undoped and noble metal (Au, Pt, Ag) decorated quasi/spherical TiO 2 nanoparticles worked also as sensing interfaces, leading to the development of a highly sensitive conductometric NO gas sensor under both dark and UV–vis light irradiation, in the first result of its kind. Furthermore, the photocatalytic activity (PCA) was also evaluated, in the gas–solid phase, by monitoring the degradation of NO x under solar-light irradiation. Au-modified TiO 2 showed improved photocatalytic efficiencies, compared to unmodified TiO 2 . [ABSTRACT FROM AUTHOR]

This paper reports on the high sensitivity of sub-spherical In 2 O 3 -Pt nanoparticles (NPs) for detecting ppb levels of acetone, a biomarker for diabetes. The In 2 O 3 -Pt NPs, in the form of monodisperse metal-oxide In 2 O 3 NPs with diameters of 6–8 nm, decorated with 2 wt% Pt metal NPs (2–3 nm) on the surface, were synthesized by a novel non-aqueous sol–gel route. NPs samples were investigated by X-ray powder diffraction (XRPD), using the advanced whole powder pattern modeling (WPPM) method, and high-resolution transmission electron microscopy (HR-TEM). The advantage of this preparative process is that it preserves metallic platinum NPs formed during the synthesis. The highly sensitive acetone sensor based on these NPs, showed a lower detection limit as low as 10 ppb or less, which is the lowest detection limit ever reported for any chemoresistive acetone sensors. This exceptional performance is likely due to the key role played by very small Pt metal NPs uniformly distributed in the In 2 O 3 -Pt nanostructure. The developed sensor would be suitable for use as a highly sensitive, practical breath acetone checker for daily diet and diabetes management and diagnosis. [ABSTRACT FROM AUTHOR]

Abstract: A general non-aqueous route was applied to the preparation of erbium oxide based ordered nanocrystalline hybrid structures. In a simple one-pot reaction process, Er3+ isopropoxide was dissolved in benzyl alcohol and reacted in an autoclave at 300 °C. This approach leads to crystalline sub-nanometer thick Er2O3 oxide layers (crystallized in the monoclinic structure) regularly separated from each other by organic layers of intercalated benzoate molecules. They display good thermal stability for temperature up to 450 °C and outstanding optical emission properties in the near infrared region interesting for optical fiber technology. [Copyright &y& Elsevier]

This study is a contribution to development of material based on transition metal oxides with application in electrochemical devices. A pyrochlore-like solid solution with general chemical formula Bi1.2Ce0.3Sb1.5CuO7 was synthesised. The pyrochlore structure was determined by X-ray powder diffraction. The pressed pyrochlore powder sample was analysed by scanning electron microscopy to show effect of substitution fraction of cerium and to determine its grain size and morphology. Energy dispersive of X-rays was performed to confirm effective substitution of bismuth for cerium. The EDX analysis was supported by X-ray photoelectron spectroscopy which also gave information on respective oxidation states of cations. Several modes of vibration due to metal-oxygen bonds of pyrochlore-like material were studied by Fourier-transform infrared spectroscopy. The results suggested that this compound contained major component of pyrochlore and minor component of CeO2. The dielectric measurements carried out at frequency 1 MHz in temperature range –40°C–90°C proved that pyrochlore compound possessed dielectric constants ranging between 12 and 28. Furthermore, owing to its high electrical conductivity, synthesised material has been utilised as bioanode in a microbial fuel cell. This bio-electrochemical device converted organic wastes into electricity using microorganisms as biocatalysts. It displayed greater electron transfer from electroactive biofilm towards the bioanode by improving its electrical energy output. The presence of pyrochlore in electrode allowed a power density of 25 mW/m2. It was almost the same as that obtained with a graphite carbon modified by the conducting polymer polypyrrole. The MFC with pyrochlore solid oxide was advantageously more stable having longer lifetime and indicating its suitability to substitute the polypyrrole at the bioanode. Besides, the colour of the coffee mac leachate in the anolyte (anode compartment) became less dark, which means that the maximum chemical oxygen demand (COD) was removed and converted into electric energy. [ABSTRACT FROM AUTHOR]

Monodisperse, ultra-small, perovskite-type SrHfO3 nanocrystals are synthesized from solutions of metallic strontium and hafnium isopropoxide in anhydrous benzyl alcohol (autoclave, 220 °C, 48 h). [ABSTRACT FROM AUTHOR]

The development of highly efficient photocatalyst under visible light still a challenge. Herein we present band gap modification of NH 2 -MIL-125 by encirclement with suitable semiconductor that possesses a narrow band gap Ag 3 PO 4 nanoparticles (NPs). The band gap of NH 2 -MIL-125 was decreased from 2.51 to 2.39 eV, making them potential candidates for photocatalytic applications. Our prepared photocatalysts were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR) and UV–vis diffuse reflectance spectroscopy (UV–vis DRS). TEM characterizations indicated that NH 2 -MIL-125 MOFs are coated with Ag 3 PO 4 NPs. The photocatalytic activity (PCA) was evaluated in the liquid-solid phase, by monitoring the degradation of an organic dye (methylene blue (MB) and rhodamine-B (RhB)) under visible-light irradiation. Furthermore, the Ag 3 PO 4 @NH 2 -MIL-125 nanocomposites shown themselves to be the most active with the reaction rate being 39 and 35 times higher than the well known Degussa P25 TiO 2 toward photocatalytic degradation of MB and RhB. [ABSTRACT FROM AUTHOR]

The porous metal–organic framework UiO-66(Zr) obtained via non modulated synthesis, has revealed to be a notable heterogeneous catalyst, enabling extremely fast and very efficient desulfurization of a multicomponent model diesel and also a real diesel fuel. [ABSTRACT FROM AUTHOR]

We applied a general non-aqueous route for the formation of mono-, bi-, tri-, tetra, hexapod and multipod magnetic spinel ferrite metal oxide (CoFe2O4) nanocrystals. The magnetic CoFe2O4 nanocrystals were characterized by X-ray diffraction, high-resolution transmission electron microscopy, Raman spectroscopy, magnetometry and Mössbauer spectroscopy, to understand their structure and magnetic properties. These CoFe2O4 nanoparticles have the smallest particle size reported ever, with a mean diameter of ∼3 nm. The coercivity was found to be larger compared to that reported in the literature for spherical particles. Mössbauer spectroscopy indicated a magnetic transition above room temperature, where 20% of the Fe ions transit to a paramagnetic state, around 400 K. From the thermal dependence of magnetic parameters, the blocking temperature was estimated to be around 425 K. These studies indicate that our CoFe2O4 nanocrystals are different from their cubic/spherical counterparts, which generally display a single domain character. These CoFe2O4 nanocrystals display a strong shape anisotropy dependent magnetic property. [ABSTRACT FROM AUTHOR]

This work aims to reduce the prices of a wide range of nanomaterials which are unreachable in the industry by using natural sources as silicon and aluminum precursors. In a previous work, silicon and aluminum have been extracted from Volclay after applying the alkaline fusion process at 550 °C, and a water treatment of this fused clay by adopting a weight ratio (1:4, fusion mass:H 2 O) to synthesize Al-MCM-41 nanomaterials. In this study, the weight ratio of fusion mass:H 2 O was increased to 1:8 to synthesize a highly structurally ordered MCM-41 under the same reaction conditions. The Al-MCM-41 nanomaterials are investigated by inductively coupled plasma optical emission spectrometry (ICP–OES), powder X-ray diffraction (XRD), N 2 adsorption–desorption measurements and scanning electron microscopy (ESEM). As a result, the increase in the weight ratio fusion mass:H 2 O generates more silica and aluminum, which allows the formation of well-ordered MCM-41 nanomaterials with high pore volume (0.70 cm 3 /g), high surface area (1044 m 2 /g), and uniform mesoporous diameter (3.67 nm); as a consequence, the increase in the weight ratio fusion mass:H 2 O leads to an increase in the mass of Al-MCM-41 (9.3 g for 1:8 compared to 5 g for 1:4), whereas the yield of production of mesoporous materials increases to 86%. [ABSTRACT FROM AUTHOR]

This study is a contribution to the development of novel materials based on transition multi metal oxides, which can be applied as photocatalysts or solid electrolytes in solid fuel cells. A new pyrochlore-like solid solution fractions with general chemical formula Bi 1.5 − x Ce x Sb 1.5 CuO 7 was synthetized and characterized using solid-state reaction and characterized by X-ray powder diffraction (XRPD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), electrical resistivity measurements and solid-state ultraviolet–visible spectroscopy (UV–Vis). The XRDP analysis revealed a high purity pyrochlore-like structure of the solid solution fractions , this being primary with cerium saturation between x = 0.2. and x = 0.4. A significant decrease of the refined cubic cell parameter was observed, in accordance with the size difference between bismuth and cerium cations. Also, a drastic drop off in electrical resistivity was observed at x = 0.4. Besides, the core level X-ray photoelectron spectroscopy technique clearly detected the presence of all elements involved in the composition of these materials, and proved the simultaneous trivalent and tetravalent oxidation states of incorporated cerium. Furthermore, secondary and back-scattered electrons scanning electron microscopy analysis allowed the monitoring of the grain size as well as the phase inhomogeneity of the solid solution fractions. Finally, it was thus found that the optical band gap energy of the solid solution fractions was about 1.8 ​eV. [Display omitted] • Elaboration of pyrochlore-like structure and his application as novel material electrodes and biological fuel cells. • Elaboration of new Ce-doped pyrochlore-like structure solid solution series. • Improvement of the electronic and/or the ionic conductivity of the synthetized materials. • Application in future as novel material electrodes in solid oxide and biological fuel cells. [ABSTRACT FROM AUTHOR]