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This work investigates the effect of the Potassium promoter and the calcination temperature on the catalytic activity in the dry reforming of methane reaction and compares the performance of the Ni, Co, Fe–Al2O3 trimetallic catalysts with the reference Ni–Al2O3. Although higher activity was achieved with the Ni–Al2O3, trimetallic catalysts resulted in a more favorable CO/H2 ratio and considerably better coke resistance. Higher calcination temperature led to the increase in coke formation which caused the sintering of the catalysts. Promoting samples with 0.5%K in order to improve the coke formation resistance, reduced the catalytic activity. [ABSTRACT FROM AUTHOR]

Zn- and Mn-doped Cerium-oxide based catalyst textured as a solid solutional as well as interfacial form was compared in CO2 hydrogenation reaction to understand the role of texture as well as dopant type. Ce0.9M0.1O2 (M = Zn, Mn) solid solution was prepared by hydrothermal method and CeO2 supported 10 mol% metal oxide (Metal = Zn, Mn) were prepared by wet impregnation method, where the catalysts were characterized by XRD, N2 adsorption/desorption isotherm, TEM, Raman spectra, HAADF-STEM and H2-TPR. During the CO2 activation reaction, CO was the major product with minor amounts of methane, ethane, methanol and ethanol. In the case of the Zn-doped CeO2 catalyst, the presence of Zn improved catalytic activity in both solid solutional and interfacial form due to the synergetic effect of Zn-Ce-based oxide. However, for MnOx/CeO2 catalysts, the CO2 consumption rate significantly decreased for 10 mol% MnOx/CeO2, Ce0.9Mn0.1O2 and Mn3O4, where the MnOx addition inhibits the reduction of CeO2. In the case of the pure CeO2, DRIFTS spectra show that formate intermediate formed by reaction between activated CO2 and OH transformed into methoxy species through formaldehyde intermediates, which leads to the formation of small amount of methanol and ethanol. [ABSTRACT FROM AUTHOR]

Heterogeneous catalysis is a chemical process achieved at solid–gas or solid–liquid interfaces. Many factors including the particle size, shape and metal-support interfaces can have significant influences on the catalytic properties of metal catalysts. The recent progress in the synthesis techniques and advanced characterization tools allow to understand the catalytic mechanisms at molecular level. In this Review, the size and shape dependent catalytic chemistry of metal nanoparticles and their electronic properties will be discussed. Then the unique catalytic chemistry at the metal-support interfaces will be discussed in details. Furthermore, the challenges of bimetallic nanoparticle catalytic chemistry will be discussed. [ABSTRACT FROM AUTHOR]

In the present study, NiO modified ZnAl2O4 and ZnO modified NiAl2O4 spinel along with pure Al2O3, ZnAl2O4 and NiAl2O4 for comparison in the CO2 hydrogenation reaction have been investigated. It was found that NiAl2O4, NiO/ZnAl2O4 and ZnO/NiAl2O4 catalysts exhibited outstanding activity and selectivity towards methane even at high temperature compared to similar spinel structures reported in the literature. NiO/ZnAl2O4 catalyst showed CO2 consumption rate of ~ 19 μmol/g·s at 600 °C and ~ 85% as well as ~ 50% of methane selectivity at 450 °C and 600 °C, respectively. The high activity and selectivity of methane can be attributed to the presence of metallic Ni and Ni/NiO/ZnAl2O4 interface under the reaction conditions as evidenced by the XRD results. High performance Ni–Zn–Al-based oxide/spinel nanostructures is synthesized and NiO/ZnAl2O4 catalyst exhibited higher catalytic activity in the CO2 hydrogenation reaction due to the presence of metal support interaction between Ni and ZnAl2O4 support. [ABSTRACT FROM AUTHOR]

• MnCo 2 O 4 has high activity & superior methane selectivity compared to published data. • MnCo 2 O 4 structure is stable and can be reactived. • Co/MnO interphase are responsible for methane production even at high temperatures. We report on a cobalt/manganese-oxide interface catalyst with outstanding activity and selectivity towards methane even at high temperatures and ambient pressure in CO 2 hydrogenation. The catalyst was formed from a MnCo 2 O 4 -based spinel structure during the oxidative-reductive pretreatment process just before the catalytic tests. Several Mn-, Fe- and Ni-containing cobaltite spinel and reverse spinel structures were tested to find the best overall performer. The reusable MnCo 2 O 4 -based structure featured a CO 2 consumption rate of ~8500 nmol*g−1*s−1. Even though methane is not the thermodynamically favoured product, it was produced with ~80% and ~50% selectivity at ambient pressure at 673 K and 823 K, respectively. This unexpected finding is linked to the presence of a unique nanostructured Co/Mn(II)O catalyst with a surface composition of Mn 3.3 Co 2.0 O 4.7 formed after the pretreatment activation step. Over this phase, the reduction of CO 2 progresses through bridge bonded formate located at the Co/Mn2+ interface and this is mostly responsible for high temperature methane formation. This hypothesis is proven here by the reported combination of ex-situ XRD, TPR, HRTEM-ED, HAADF-EDX and in-situ NAP-XPS and DRIFTS techniques. [ABSTRACT FROM AUTHOR]

A new porosity determination method for nano- and sub-micron particles is proposed, which is based on single particle inductively coupled plasma mass spectrometry (spICP-MS) measurements. The performance of the new method was tested on core–shell Ag–Au, hollow Au and mesoporous SiO2 nanoparticles of different sizes and porosities and it was found that its accuracy and precision (e.g. 1–2 rel.%) are comparable to those of reference methods, such as small angle X-ray scattering (SAXS), gas adsorption or transmission electron microscopy imaging (TEM). It can be applied to nano- and submicron particles in the complete mesoporous pore (2–50 nm) range. The application to macroporous particles is also possible, but it is limited in size to particles that can be fully decomposed by the plasma. The proposed new spICP-MS method provides an advantageous set of features that is unparalleled among the porosity determination methods, namely (i) it only requires a very small amount of particulate sample (micrograms or even less) in the form of a dilute dispersion (e.g. in a 105 mL−1 particle concentration), so there is not even a need for a dry sample; (ii) it works for open and closed pores equally well; (iii) the measurement and calculation are quick and simple, and only need the external diameter of the particle (from e.g. electron microscopy or dynamic light scattering (DLS) measurements) as input. The overall porosity determined can also be used to calculate the density of the particles, a feat which is not easy to achieve from such a small amount of sample. [ABSTRACT FROM AUTHOR]

Fossil fuel depletion, global warming, climate change, and steep hikes in the price of fuel are driving scientists to investigate commercial and environmentally friendly energy carriers like hydrogen. Steam methane reforming (SMR), a current commercial route for H 2 production, has been considered the best remedy to fulfill the requirements. Despite the remarkable quantity of H 2 produced by the SMR, this technology still faces major challenges such as catalyst deactivation due to the sintering of metal nanoparticles, coking, and generation of a large quantity of CO 2. Firstly, the effects of catalyst types, kinetic models, and operating conditions on high-yield H 2 production, the evolution path from gray to blue, via the conventional SMR are comprehensively reviewed. Secondly, exploiting intensified techniques such as membrane technology, sorption, fluidization, and chemical looping for SMR to blue H 2 are discussed in detail. Further, a novel and sustainable path for the SMR process, hybridizing the use of novel materials and emerging technologies to produce turquoise H 2 , is proposed. Finally, the critical points for steam reforming process technology that can help leverage environmental, social, and governance (ESG) profiling have been discussed. [Display omitted] • Evolution path from gray to turquoise H 2 via catalytic SMR is discussed. • Recent advances in catalysis, kinetic models, and operating conditions are reviewed. • The importance of SMR process intensification for blue H 2 production is highlighted. • A novel and sustainable path for the SMR process to efficiently produce turquoise H 2 is proposed. • Key points for SMR technology that can help leverage ESG profiling are listed. [ABSTRACT FROM AUTHOR]

In this study, the performance of five analytical techniques applicable to the determination of the load concentration of ultra small nanoparticles in a Pt/SiO2 nanocomposite was critically evaluated. Four of the techniques (SEM-EDS, TEM imaging, XPS and solution-mode ICP-MS) are often used for the characterization of nanoparticles, whereas single particle ICP-MS (spICP-MS) is an upcoming, novel methodology. After experimentally testing and discussing the pros and cons of each analytical technique, it was found that spICP-MS is one of the most accurate, precise and practical techniques for the analysis of nanocomposites. This technique works directly with dispersions, the measurement only takes a few minutes, it gives highly reliable results, largely free from interference from precursor residues and can also provide additional information about the particles. Although the individual measurement of ultra small nanoparticles is not yet possible by spICP-MS, the cumulative signal from such load particles in a nanocomposite allows the accurate determination of the load concentration. The spICP-MS result was concordant with the result obtained by TEM imaging, whereas SEM-EDS, XPS and solution-mode ICP-MS strongly overestimated the concentration. [ABSTRACT FROM AUTHOR]

Strontium titanate (STO) photocatalysts were prepared via a slightly modified Pechini sol–gel method. A unique rapid calcination technique with a short exposure time was used to obtain crystalline products. The samples were characterized by X-ray diffractometry, scanning electron microscopy, diffuse reflectance spectroscopy, infrared spectroscopy, nitrogen adsorption–desorption measurements, and X-ray photoelectron spectroscopy. Their photocatalytic activity was evaluated by the photocatalytic oxidation of phenol, oxalic acid, and chlorophenol under UV light irradiation using commercial STO as a reference. These pollutants, together with glucose and propanol, were used to investigate the stability of the samples against various functional groups. All our samples exhibited higher photocatalytic activity than the commercial STO reference. With increasing calcination temperature, the crystallinity and primary crystallite sizes increased while the band gaps and specific surface areas decreased. The photocatalytic activity of the most efficient sample was explained by the presence of SrCO3 on its surface. The STO catalysts were highly stable as they largely retained their crystalline composition after exposure to chemicals with different functional groups. Finally, we compared the costs associated with the unique calcination technique with a more conventional one and found that our method is ~35% more cost-effective. [ABSTRACT FROM AUTHOR]

Abstract: The adsorption of cyclohexane, cyclohexene, 1,3-cyclohexadiene, 1,4-cyclohexadiene and benzene was studied on pristine and shortened multi-wall carbon nanotubes, SBA-15 and a novel high surface area mesoporous carbon (CMH). Data were fitted with the Freundlich adsorption equation and the correlation between the fitted parameters and quantitative structure–activity relationships (QSAR) descriptors of the adsorbates was analyzed. Adsorption on carbon nanotubes is more sensitive to the partial pressure of unsaturated adsorbates, whereas SBA-15 is more sensitive to saturated partners. CMH is a neutral material that appears to be particularly useful for studying catalyst particle efficiency without the influence of the support itself. [Copyright &y& Elsevier]

[Display omitted] • A series of 5 wt% NiO-xP-Al 2 O 3 with different phosphorus loading contents (x = 0, 5, 15 and 20 wt%) were prepared by a modified sol-gel method. • All the catalysts reach the highest conversion at 600 °C with 61.54 %, 62.89 %, 63.88 % and 66.13 % respectively for 5 wt% NiO-Al 2 O 3 , 5 wt% NiO-5P-Al 2 O 3 , 5 wt% NiO-15P-Al 2 O 3 and 5 wt% NiO-20P-Al 2 O 3 catalysts. • Ni/NiO/Ni 2 P/Ni 5 P 12 /AlPO 4 interfacial species were detected on the surface as active species on the used catalysts by X-ray photoelectron spectroscopy. • The formation ratio of the metal-phosphide is relatively low ∼3−5 %, and this atomic concentration is decreasing with the rising of the phosphate content. However, the nickel enrichment in the surface layer presumable in Ni 2 P/Ni 5 P 12 form is very likely according to the P 2p spectra and the authors assume that could be responsible for the enhanced catalytic activity. A series of 5 wt% NiO-xP-Al 2 O 3 with different phosphorus loading contents (x = 0, 5, 15 and 20 wt%) were prepared by a modified sol-gel method. A significant promotional effect of phosphorus on NiO-Al 2 O 3 in CO 2 hydrogenation is observed. All the catalysts reach the highest conversion at 600 °C with 61.54 %, 62.89 %, 63.88 % and 66.13 % respectively for 5 wt% NiO-Al 2 O 3 , 5 wt% NiO-5P-Al 2 O 3 , 5 wt% NiO-15P-Al 2 O 3 and 5 wt% NiO-20P-Al 2 O 3 catalysts. Ni/NiO/Ni 2 P/Ni 5 P 12 /AlPO 4 interfacial species were detected on the surface as active species on the used catalysts by X-ray photoelectron spectroscopy. The formation ratio of the metal-phosphide is relatively low ∼3−5 %, and this atomic concentration is decreasing with the rising of the phosphate content. However, the nickel enrichment in the surface layer presumable in Ni 2 P/Ni 5 P 12 form is very likely according to the P 2p spectra and the authors assume that could be responsible for the enhanced catalytic activity. [ABSTRACT FROM AUTHOR]

Rh is one of the most effective metals in several technologically important heterogeneous catalytic reactions, like the hydrogenation of CO2, and CO, the CO+H2O reaction, and methane and ethanol transformations. Titania and titanates are among the most frequently studied supports for Rh nanoparticles. The present study demonstrates that the nature of the support has a marked influence on the specific activity. For comparison, the catalytic activity of TiO2 P25 is also presented. It is pointed out that a certain amount of Rh can be stabilized as cation (Rh+) in ion-exchange positions (i.e., in atomic scale distribution) of the titanate framework. This ionic form does not exists on TiO2. We pay distinguished attention not only to the electronic interaction between Rh metal and the titania/titanate support, but also to the Rh-induced phase transitions of one-dimensional titanate nanowires (TiONW) and nanotubes (TiONT). Support transformation phenomena can be observed in Rh-loaded titanates. Rh decorated nanowires transform into the TiO2(B) phase, whereas their pristine counterparts recrystallize into anatase. The formation of anatase is dominant during the thermal annealing process in both acid-treated and Rh-decorated nanotubes; Rh catalysis this transformation. We demonstrate that the phase transformations and the formation of Rh nanoclusters and incorporated Rh ions affect the conversion and the selectivity of the reactions. The following initial activity order was found in the CO2 + H2, CO + H2O and C2H5OH decomposition reactions: Rh/TiO2 (Degussa P25) ≥ Rh/TiONW > Rh/TiONT. On the other hand it is remarkable that the hydrogen selectivity in ethanol decomposition was two times higher on Rh/TiONW and Rh/TiO(NT) catalysts than on Rh/TiO2 due to the presence of Rh+ cations incorporated into the framework of the titanate structures. [ABSTRACT FROM AUTHOR]

[Display omitted] • Mixed Na-Fe 3 O 4 and Fe 5 C 2 can enhance the performance of CO 2 hydrogenation to C 5+. • An optimal oxide/carbide ratio is crucial for achieving high yields of C 2 -C 4 olefins and C 5+ hydrocarbons. • Closer proximity of oxide and carbide hindered CH 4 formation and olefin hydrogenation. • Oxide/carbide reduction can enhance carbon shell graphitization and C 5+ formation. CO 2 hydrogenation into sustainable chemical feedstocks and fuels is a pivotal focus of energy research. Fe-based catalysts have emerged as promising candidates due to their high efficiency in the CO 2 hydrogenation toward C 2 –C 4 olefins and C 5+ hydrocarbons. Fe 5 C 2 is known as the active phase of the CO 2 hydrogenation. Therefore, it is imperative to discern the roles of active phases in product distribution. Accordingly, in the present study, Fe 5 C 2 is synthesized separately and physically mixed with Na-Fe 3 O 4. The effects of oxide/carbide ratio, the proximity of active phases, and reduction treatment are investigated. The results show that adding carbide to oxide in an appropriate ratio significantly increases CO 2 conversion due to the controlled reduction of the oxide phase and enhanced CO 2 adsorption. Additionally, a closer distance (mixed-powder pellets) between Na-Fe 3 O 4 and Fe 5 C 2 results in higher selectivity for C 2 -C 4 olefins and C 5+ hydrocarbons and less CH 4. Furthermore, the graphitized layers of reduced catalyst (R-Na-Fe 3 O 4 /Fe 5 C 2 (70/30 wt%)) enhance the selectivity to C 2 -C 4 olefins (40 %) and C 5+ hydrocarbons (35 %) at around 40 % CO 2 conversion. In contrast, amorphous carbon in the non-reduced catalyst (NR-Na-Fe 3 O 4 /Fe 5 C 2 (70/30 wt%)) favors more C 2 -C 4 paraffins and CH 4. Therefore, the interplay between the influential factors, i.e., oxide/carbide ratio, spatial distance, and reduction treatment, can result in tailoring an efficient CO 2 hydrogenation catalyst toward the formation of valuable hydrocarbons. [ABSTRACT FROM AUTHOR]

The implementation of supported metal catalysts heavily relies on the synergistic interactions between metal nanoparticles and the material they are dispersed on. It is clear that interfacial perimeter sites have outstanding skills for turning catalytic reactions over, however, high activity and selectivity of the designed interface‐induced metal distortion can also obtain catalysts for the most crucial industrial processes as evidenced in this paper. Herein, the beneficial synergy established between designed Pt nanoparticles and MnO in the course of the reverse water gas shift (RWGS) reaction resulted in a Pt/MnO catalyst having ≈10 times higher activity compared to the reference Pt/SBA‐15 catalyst with >99 % CO selectivity. Under activation, a crystal assembly through the metallic Pt (110) and MnO evolved, where the plane distance differences caused a mismatched‐row structure in softer Pt nanoparticles, which was identified by microscopic and surface‐sensitive spectroscopic characterizations combined with density functional theory simulations. The generated edge dislocations caused the Pt lattice expansion which led to the weakening of the Pt−CO bond. Even though MnO also exhibited an adverse effect on Pt by lowering the number of exposed metal sites, rapid desorption of the linearly adsorbed CO species governed the performance of the Pt/MnO in the RWGS. [ABSTRACT FROM AUTHOR]

The implementation of supported metal catalysts heavily relies on the synergistic interactions between metal nanoparticles and the material they are dispersed on. It is clear that interfacial perimeter sites have outstanding skills for turning catalytic reactions over, however, high activity and selectivity of the designed interface‐induced metal distortion can also obtain catalysts for the most crucial industrial processes as evidenced in this paper. Herein, the beneficial synergy established between designed Pt nanoparticles and MnO in the course of the reverse water gas shift (RWGS) reaction resulted in a Pt/MnO catalyst having ≈10 times higher activity compared to the reference Pt/SBA‐15 catalyst with >99 % CO selectivity. Under activation, a crystal assembly through the metallic Pt (110) and MnO evolved, where the plane distance differences caused a mismatched‐row structure in softer Pt nanoparticles, which was identified by microscopic and surface‐sensitive spectroscopic characterizations combined with density functional theory simulations. The generated edge dislocations caused the Pt lattice expansion which led to the weakening of the Pt−CO bond. Even though MnO also exhibited an adverse effect on Pt by lowering the number of exposed metal sites, rapid desorption of the linearly adsorbed CO species governed the performance of the Pt/MnO in the RWGS. [ABSTRACT FROM AUTHOR]

The solar chimney power plant (SCPP) is a straightforward and clean technique to generate electricity from solar radiation. However, this technology still faces major challenges, such as low efficiency, which has hindered its industrialization. This study experimentally develops a novel collector design to improve the solar chimney collector's efficiency. The new design includes metallic tubes as solar radiation absorbers hung from the canopy of the collector. The metallic tubes are open at the top and sealed with transparent sheets at the bottom to decrease the solar radiation reflected into the ambient air. Experimental and 3-D computational fluid dynamics (CFD) analyses are performed to validate the new design. The effects of hanging metallic tubes on temperature and velocity distribution are explored. The temperature increased by about 5 K at the chimney inlet, causing a roughly 8% rise in collector efficiency due to the fact that metallic tubes operate as an extended surface. The impact of various tube geometries on solar chimneys' efficiency is examined. The CFD findings reveal that the metallic tube geometry variation has considerably impacted the collector's efficiency. Thus, the collector efficiency is increased by changing tube diameter by around 33.7%, similar to changing tube length by 30%. [Display omitted] • A new solar chimney's collector design was experimentally developed and compared with CFD simulation. • Effects of hung metallic tubes on air temperature and velocity distribution were explored. • Effects of various metallic tube geometries on the collector's efficiency were studied and compared. • The collector efficiency increased from 25% in conventional solar chimneys to 33.90% in the improved ones. [ABSTRACT FROM AUTHOR]

In this study, lightweight cordierite-mullite ceramics with high strength and high thermal-shock resistance were successfully synthesized by solid-state method with the usage of hollow ceramic microspheres. After careful physico-chemical and mechanical characterization, we gained an economical cordierite material with a low bulk density of 1.40 g/cm3 with an apparent porosity of 44.78%, a flexural strength of 20.17 MPa and a coefficient of thermal expansion of 2.26 × 10−6 oC−1 compared to the bulk counterpart with a bulk density of 2.00 g/cm3 with an apparent porosity of 25.75%, a flexural strength of 23.69 MPa and a coefficient of thermal expansion of 2.47 × 10−6 oC−1. As a catalyst support of Na-FeO x , the economical cordierite has proved the same stability and activity in CO 2 hydrogenation towards C 5+ fuels as bulk cordierite-based catalyst counterparts. [ABSTRACT FROM AUTHOR]

A low ratio of polymerization is a major problem in resin-based composites. In this paper, the plasmonic effect of gold-covered silica nanoparticles on the physicochemical and mechanical properties of bisphenol A diglycidyl dimethacrylate (Bis-GMA), triethylene glycol dimethacrylate (TEGDMA) and urethane dimethacrylate (UDMA) green light-photopolymerizable dental resin was investigated at an intensity of 1.4 mW/cm2 for 40 s. Transmission electron microscopy (TEM) showed silica of about 350 nm covered with 12–15 nm gold nanoparticles (Au NPs) at 100% nominal coverage. Five different concentrations of bare and patchy silica particles were used; in the latter composite, the calculated Au wt% were 0.0052 wt%, 0.0104 wt%, 0.0208 wt%, 0.04160 wt%, and 0.0823 wt%. The plasmon peak of patchy silica-filled nanocomposite overlapped with the absorption of Irgacure 784 photoinitiator and green LED light emission peak. The effect of plasmon-enhanced polymerization achieved with green light illumination was analyzed using diametral tensile strength (DTS), differential scanning calorimetry (DSC), surface plasmon resonance imaging (SPRi), and degree of conversion (DC) based on Raman spectroscopy. The values of the Au NP with 0.0208 wt% was found to be maximum in all the measured data. Based on our result, it can be concluded that the application of patchy silica particles in dental resin can improve the polymerization ratio and the mechanical parameters of the composite. [ABSTRACT FROM AUTHOR]

Glucose-to-fructose isomerization is the key process in the reaction sequence that can lead to the total conversion of biomass into valuable fine chemicals. However, it is challenging to find an efficient, cost-effective- and waste-minimized process to produce High Fructose Corn Syrup (HFCS) without using non-green approaches. To this end, hydrotalcite (MgAl-layered double hydroxides (MgAl-LDH)) catalyzed glucose isomerization in ethanol seemed to be one of the most promising processes in the last decade. In contrast to the well-studied reaction carried out in aqueous solutions, when ethanolic solutions are used, many potentially important properties of the LDHs cannot be studied in terms of how they affect their own catalytic abilities. Neither the effect of the basic site distribution, nor the morphological aspects and the role of surface hydration have been elucidated so far. In this study, the systematic alteration of the textural and structural parameters of hydrotalcites and hydrocalumites (Ca2Al-LDH) revealed clear structure–activity-selectivity relationships. These indicate that the rate-determining factor is the hydrophilicity and the LDH surface factors affecting it, which determine the catalytic performance of the LDH catalyst more than any other factor. This is evidenced by the fact that the catalytic efficiency of hydrotalcites can be improved by reducing their basicity. When isomerizations catalyzed by the easily recyclable LDH with suitable surface features are carried out, a truly similar catalytic performance (71% glucose conversion, 83% fructose selectivity, 59% fructose yield) can be achieved as was previously described, but at a significantly lower reaction temperature (120 °C → 80 °C). [ABSTRACT FROM AUTHOR]

Pt nanoparticles with controlled sizes between 1.6-7.0 nm were anchored onto the surface and pores of SBA-15 silica support. The catalysts were characterized by TEM-ED, BET, XRD, and ICP-MS techniques and were tested in liquid phase hydrosilylation of phenylacetylene with triethylsilane. The activity of the 7.0 nm Pt nanoparticles anchored onto the surface of SBA-15 in hydrosilylation (TOF = 0.107 molecules·site-1·s-1) was ~2 times higher compared to the 5.0 nm Pt/SBA-15 (TOF = 0.049 molecules·site-1·s-1) catalyst and ~10 times higher compared to the 1.6 nm Pt/SBA-15 (TOF = 0.017 molecules·site-1·s-1) catalyst. Regarding the selectivity, bigger nanoparticles produced more vinylsilane-type products (α- and β-(E)-products) and less side products (mainly ditriethylsilane, triethyl(1-phenylethyl)silane and triethyl(phenethyl)silane derived likely from the reduction of the vinylsilane products). However, the selectivity towards the β-(E)-triethyl(styryl)silane was higher in the case of 1.6 nm Pt/SBA-15 catalyst compared to 5.0 nm Pt/SBA-15 and 7.0 nm Pt/SBA-15, respectively, which can be attributed to the beneficial effect of the size differences of the Pt nanoparticles as well as the differences of the quality and quantity of Pt/SiO2 interfaces. [ABSTRACT FROM AUTHOR]

The steam reforming of ethanol (SRE) is a key process for the production of H2 and other vital hydrocarbons. The present work describes the synthesis of Platinum‐Gallium (Pt−Ga) nanoalloys supported on mesostructured cellular foam (MCF‐17) via ultrasound‐assisted impregnation method. Ga was substituted with Pt in different wt.% i. e. Pt/MCF‐17, Pt99.9Ga0.1/MCF‐17, Pt99Ga1/MCF‐17, and Pt90Ga10/MCF‐17 and was evaluated towards the SRE at a temperature range of 473K‐773 K towards hydrogen (H2), acetaldehyde (CH3CHO), diethylether (DEE), ethylene (C2H4), carbon monoxide (CO), carbon dioxide (CO2), methane (CH4), and ethane (C2H6). The SRE activity and H2 formation rate with Pt90Ga10/MCF‐17 catalyst were observed to be 68.1 % and 3047.2 nmole g−1 sec−1, which is 9.8 and 4.5 times more than the Pt/MCF‐17 counterparts. Moreover, as observed from DRIFTS, NH3‐TPD and XPS studies Ga showed high interaction with Pt in the electron deficit state which resulted in the increased dehydrogenating and acidic properties that resulted in a higher yield of H2. [ABSTRACT FROM AUTHOR]

Strontium titanates were prepared with different morphologies by varying the ratio of solvents used during the synthesis. The effects of morphology and solvent (ethylene glycol to water) ratio were investigated both on the structure and photocatalytic activity of the samples. Structural properties were determined by X-ray diffraction, scanning electron microscopy, diffuse reflectance spectroscopy, and nitrogen adsorption measurements. The photocatalytic activity of the samples was evaluated by the photocatalytic oxidation of phenol and by the photocatalytic reduction of carbon dioxide. The ratio of solvents notably influenced the morphology, strontium carbonate content, primary crystallite size, and specific surface area of the samples. Samples prepared at low ethylene glycol to water ratios were spherical, while the ones prepared at high ethylene glycol to water ratios could be characterized predominantly by lamellar morphology. The former samples were found to have the highest efficiency for phenol degradation, while the sample with the most well-defined lamellar morphology proved to be the best for CO2 reduction. [ABSTRACT FROM AUTHOR]

Highlights: [•] Titanate nanotubes were utilized in Ca2+ and Mg2+ removal in an ion-exchange unit. [•] The highest measured value of the total ion-exchange capacity was 1.2mmolg−1. [•] The ion-exchange capacity decreased to 0.66mmolg−1 in the third cycle. [•] Capacity loss was due to irreversible binding of Ca2+ to strong adsorption sites. [•] The Mg2+/Na+ exchange was reversible. [ABSTRACT FROM AUTHOR]

András Sápi et al. have reported on a nanodesigned Pt/MnOx interface that enhances the activity of the reverse water gas shift (RWGS) reaction. The interface generates edge dislocations, which destabilize and release linearly adsorbed CO from the Pt nanoparticle, resulting in improved catalytic performance. In addition, other articles in the journal discuss topics such as biosensors, cyclooligomers, photochemistry, and singlet fission. The authors of these articles explore various scientific advancements and their applications. [Extracted from the article]

András Sápi et al. have reported on a nanodesigned Pt/MnOx interface that enhances the activity of the reverse water gas shift (RWGS) reaction. The interface generates edge dislocations, which destabilize and release linearly adsorbed CO from the Pt nanoparticle, resulting in improved catalytic performance. In addition, other research articles in the journal cover topics such as biosensors, cyclooligomers, photochemistry, and singlet fission. [Extracted from the article]

As-quenched and stress field annealed FINEMET ribbons were irradiated with 246 MeV energy Kr, 470 MeV energy Xe and 720 MeV energy Bi ions and investigated by Fe Mössbauer spectroscopy and XRD methods. The change in relative areas of the 2nd and 5th lines in the Mössbauer spectra indicated significant changes in the magnetic anisotropy of both as-quenched and stress annealed FINEMET due to irradiation with swift heavy ions. Differences were observed between the effect of irradiations with various ions having different energy and fluence. The effect of irradiation on the magnetic orientation in FINEMET was explained in terms of radiation induced defects. The swift heavy ion irradiation can be applied to produce FINEMET ribbons with more favorable soft magnetic properties for technological applications. [ABSTRACT FROM AUTHOR]

Abstract: Polyacrylonitrile (PAN) layers were cast from dimethyl-formamide solutions onto quartz substrates by spin coating and subsequently annealed at up to 1000°C in N2 atmosphere. Carbonization was catalyzed by nickel or cobalt added to the solution as acetate salts. The synthesized films were approx. 970nm thick and were characterized by Raman and infrared spectroscopy as well as thermogravimetric and electrical conductance measurements. We discuss the effects of carbonization temperature and metal concentration on the morphology, composition and electrical properties of the formed carbon layer. Increasing the amount of catalyst and the pyrolysis temperature was beneficial for the process and resulted in carbonaceous films with a higher degree of structural order as evidenced by the decreasing Raman ID/IG ratio and the increasing electrical conductivity of the films. Cobalt is a better catalyst for PAN carbonization than nickel as far as the structure of the product film is concerned. [Copyright &y& Elsevier]

We report the enhanced photocatalytic performance of CO 2 reduction by introducing noble metal-deposited TiO 2 photocatalysts (NMD/TiO 2) under both visible light irradiation (VLI) and UV. It was found that NMD-TiO 2 samples demonstrated an expanded ability for light absorption, resulting in an improved photoefficiency for CO 2 reduction and selectivity towards carbon monoxide (CO). The conversion yields of CO 2 to CO followed the order: Rh >Ru >Pt and with Rh/TiO 2 reached 10.65 μmol/g cat (under visible light) and 7.84 μmol/g cat (under UV), which are ∼3 and 10 times more as compared to pristine anatase TiO 2 (0, and 2.43 μmol/g cat). Various factors were addressed including theoretical studies via DFT revealed that the formation of new impurity energy state levels in NMD/TiO 2 , which act as acceptor levels. Moreover, DRIFTS studies showed that the H-O-C-O and formyl (H 2 CO) species were the important intermediates towards the hydrogenation of CO 2 to CO. Also, a charge transfer mechanism toward CO 2 reduction was elucidated. [Display omitted] • Controlled-size noble metals/TiO 2 composite were used in CO 2 reduction under UV and visible light. • NMD-TiO 2 showed enhanced light absorption ability which lead to the highest yield of CO (10.65 μmol/gcat). • DFT revealed the formation of new impurity energy state levels, which act as acceptor levels. • DRIFTS showed H-O-C-O and formyl (H 2 CO) species were key intermediates in photo-RWGS. [ABSTRACT FROM AUTHOR]

Birnessite structured MnO x with tuned potassium, copper and water content in the interlayer spacing is produced by a simple and cost-effective method. The new structures are investigated by XRD, Raman spectroscopy, SEM, EDX, HRTEM, DLS, TG, and DSC. Our study demonstrates a successful intercalation process to produce birnessites with mixed interlayer cations. Both Birnessite and Cu2+/Birnessite structure have a nanosheet-like morphology where the sizes of the copper-treated birnessite nanoparticles are drastically decreased compared to the copper ion free structures. The specific surface area is increased from 21.6 m2/g to 77.8 m2/g in the presence of copper as a result of a longer ageing process. Our study reveals that the electron transfer numbers of Birnessite and Cu2+/Birnessite are about 3.40 and 3.65, respectively in the oxygen reduction reaction. Both as-synthesized pristine Birnessite and copper tuned Birnessite are a promising candidate for a cheap, noble metal-free electrocatalyst for fuel cell applications. • K-, Cu-Birnessite nanostructures by cheap oone pot method for ORR. • Birnessite showed high activity in ORR with the 4-electron pathway. • Cu effecting the Mn3+/Mn4+ ratio resulting in good ORR activity. [ABSTRACT FROM AUTHOR]

[Display omitted] • α-MoO 3 - crystallographic planes' ratio was tuned by calcination. • Orientation changes were induced via hydrothermal recrystallization. • The presence of α-MoO 3 inhibits the Fenton degradation of methyl orange. • The inhibitive effect is determined by the structural properties of α-MoO 3. • Fenton inhibition was persistent despite increased reagents concentration. MoO 3 is an intensively researched metal oxide, and it is considered a promising visible light driven photocatalyst and an excellent adsorbent of cationic dyes. In the present work orthorhombic α-MoO 3 was obtained v ia calcination of ammonium heptamolybdate where structural modifications were induced by changing the applied calcination temperature (400–750 °C). Further subtle structural (crystallographic plane ratio) and morphological modifications were achieved via hydrothermal recrystallization. Differences between samples were clearly evidenced by various characterization techniques, especially in the case of the crystalline facet ratio and the morphology. The differently structured α-MoO 3 samples were investigated as an inhibitor for Fenton reactions where the organic compounds decomposition relies on the generation of OH radicals. It was found that α-MoO 3 strongly inhibits the rate of methyl orange (MO) decolorization. This might imply that MoO 3 could be a OH radical scavenger since Fenton reactions' effectivity relies on the presence of OH and O 2 – radicals. We demonstrated that the inhibition efficiency of α-MoO 3 correlates strongly with the acidification rate of the aqueous solution in the presence of α-MoO 3. However, this pH decline was consistent with crystalline facet ratio within a sample series, while the recrystallized samples disprove this structural connection showing a more complex relationship between the structural characteristics of α-MoO 3 and its inhibitive properties of Fenton reactions. The present work pointed out that MoO 3 can inhibit reactions which are based on intensive OH radical generation processes such as photocatalysis. [ABSTRACT FROM AUTHOR]

China is working to boost the manufacture, market share, sales, and use of NEVs to replace fuel vehicles in transportation sector to get carbon reduction target by 2060. In this research, using Simapro life cycle assessment software and Eco-invent database, the market share, carbon footprint, and life cycle analysis of fuel vehicles, NEVs, and batteries were calculated from the last five years to next 25 years, with a focus on the sustainable development. Results indicate globally, China had 293.98 m vehicles and 45.22% worldwide highest market share, followed by Germany with 224.97 m and 42.22% shares. Annually China's NEVs production rate is 50%, and sales account for 35%, while the carbon footprint will account for 5.2 E+07 to 4.89 E+07 kgCO2e by 2021–2035. The power battery production 219.7 GWh reaches 150%–163.4%, whereas carbon footprint values in production and use stage of 1 kWh of LFP 44.0 kgCO 2 eq, NCM-146.8 kgCO 2 eq, and NCA-370 kgCO 2 eq. The single carbon footprint of LFP is smallest at about 5.52 E+09, while NCM is highest at 1.84 E+10. Thus, using NEVs, and LFP batteries will reduce carbon emissions by 56.33%–103.14% and 56.33% or 0.64 Gt to 0.006 Gt by 2060. LCA analysis of NEVs and batteries at manufacturing and using stages quantified the environmental impact ranked from highest to lowest as ADP > AP > GWP > EP > POCP > ODP. ADP(e) and ADP(f) at manufacturing stage account for 14.7%, while other components account for 83.3% during the use stage. Conclusive findings are higher sales and use of NEVs, LFP, and reduction in coal-fired power generation from 70.92% to 50%, and increase in renewable energy sources in electricity generation expectedly will reduce carbon footprint by 31% and environmental impact on acid rain, ozone depletion, and photochemical smog. Finally, to achieve carbon neutrality in China, the NEVs industry must be supported by incentive policies, financial aid, technological improvements, and research and development. This would improve NEV's supply, demand, and environmental impact. • Annually China's NEVs production rate is 50%, and sales account for 35%. • 1 kWh NCA battery has same environmental impact as 8.4 kWh LFP, and 7.2 kWh SSBs. • In China NEVs, batteries will reduce CO 2 emission by 0.64 Gt to 0.006 Gt before 2060. • Carbon footprint values of 1 kWh LFP and SSBs in production stage are smallest than NCM. • Incentive policies and technology advancements would boost NEVs production and use. [ABSTRACT FROM AUTHOR]

A versatile controlled-release method was developed for the in situ growth of graphdiyne on arbitrary substrates. Cu2+-Ions escaped from the polyvinylpyrrolidone/copper acetate film on the surface of various substrates (e.g. SiO2, ZnO, Al, etc.), acting as the catalyst for the acetylenic coupling reaction. [ABSTRACT FROM AUTHOR]

Photoelectrochemical water splitting can become efficient by grafting co-catalysts on semiconductors that improve the interfacial oxygen evolution reaction. We applied a simple non-noble metal pre-catalyst, [FeII(PBI) 3 ]2+ (PBI is 2-(2′-pyridyl)benzimidazole ligand) for this purpose on a nanopyramidal BiVO 4 semiconductor that was morphologically optimal for efficient light harvesting, but its performance suffered from V-poor surface recombination sites. The [FeII(PBI) 3 ]2+ in situ transformed to α -Fe 2 O 3 nanoparticles on V-vacant areas of BiVO 4 mending their photocurrent-limiting effect. Photoelectrochemistry at pH 8.2 confirmed that the α -Fe 2 O 3 co-catalyst improved the charge transfer efficiency by an order of magnitude, suppressed the recombination in the bulk and reduced the charge transfer resistance. Overall, the α -Fe 2 O 3 suppressed the recombination on the V-poor surface, while at high potentials it provided high-valent centers for the oxygen evolution. The resulting photocurrent density far exceeding that of BiVO 4 or samples modified by FeCl 3 or Fe(NO 3) 3 underlines the metallochaperone-like effect of the PBI ligand. [Display omitted] • BiVO 4 nanopyramids modified using a molecular Fe pre-catalyst for water oxidation. • in situ formed nano-α-Fe 2 O 3 bind selectively at V-vacant sites of the photoanode. • at high potentials, the co-catalyst favors the kinetics of oxygen evolution reaction. • at low potentials, the surface hole recombination is reduced by α-Fe 2 O 3. [ABSTRACT FROM AUTHOR]

We report our results on exploiting the different reactivities present in the catalytic cycle of the Pd/AlO catalyzed redox isomerization of allyl alcohol. We show that the reactivity of allyl alcohol derived acrolein and enol can be involved in further cascade reactions leading to a diverse set of products. While the oxidation product acrolein can react via Michael and oxa-Michael reactions, the isomerization product enol can be readily involved in aldol condensation processes. Salicylaldehydes, that are able to react on their electrophilic carbonyl and nucleophilic OH-groups with allyl alcohol derived enol and acrolein, respectively, are used to explore conditions where the structure of the product heterocycles can be controlled. Graphical Abstract: [ABSTRACT FROM AUTHOR]

In this paper, the improvement in room temperature ethanol sensing characteristics of zinc peroxide (ZnO 2 ) based hybrid thin films is presented by the combination of the beneficial sensing properties of mesoporous materials and reflectometric interference spectroscopy (RIfS). The hybrid thin films were prepared by Layer-by-Layer (LbL) self-assembly method from ZnO 2 nanoparticles, polyelectrolyte [poly(acrylic acid), PAA] and/or mesoporous silica (MPS). The expected improved sensing properties were attributed to the fractal properties and high specific surface area ( a s ) of the mesoporous coating/interlayer material, which was evidenced by small angle X-ray scattering (SAXS) and N 2 sorption measurements (a s > 650 m 2 /g). The sensor tests showed that the detection limit of the thin films is in the sub-ppm range (<500 ppb). Applying silica foam (SF) as surface coating or interlayer material in the sandwich-structured thin film (ZnO 2 /SF) improved the optical response (Δl: wavelength shift) compared to the ZnO 2 /PAA thin layer, but the sensitivity showed non-linear characteristic and signal drift. The thin film with mixed structure (ZnO 2 /PAA/ZnO 2 /SF) showed linear sensitivity (Δλ/Δc = 0.6 nm/ppm) in the 0.5–12 ppm range with an acceptable selectivity and stable baseline. Testing the sensor in extended (up to 40 ppm) concentration range showed only a slight quadratic deviation from linear behavior with R 2 = 0.9987. [ABSTRACT FROM AUTHOR]

The visible light photoelectrical properties of a p-type mesoporous nickel oxide (MNO) support was investigated upon the decoration of size controlled, 1.6 nm, 6.4 nm and 7.9 nm Pt nanoparticles. The near room temperature photoelectrical response of the MNO was 3 times higher after decoration of 1.6 nm Pt nanoparticles with a loading of 1 wt%. MNO decorated with smaller Pt nanoparticles showed the highest photoresponse. The surrounding atmosphere has striking effect on the photoelectrical behavior, as adsorbed oxygen induced 32% lower photoelectrical response compared to that of argon. The noble metal nanoparticles show both electronic and chemical sensitization: the first functioning as an electron sink resulting in a new band structure of the photocatalyst, and the second interacting chemically with the oxygen and argon adsorbed from the environment. A model is proposed using heterojunctions theory comprising a new induced oxygen potential that may explain the lower photoresponse in the presence of oxygen. [ABSTRACT FROM AUTHOR]

• Develop of mechanochemical preparation of the nickel-poor/aluminum-rich LDHs. • Synthesis of bromide, iodide, perchlorate, sulfamate containing LDHs for the first time. • Detailed structural, thermal and optical characterizations of the solids. • Influence of quality of interlayer anions on the CO 2 hydrogenation pathways. • Comparative catalytic study of the LDHs and co-precipitated NiAl-hydroxides. A simple synthetic route of preparing NiAl 4 -layered double hydroxides (LDHs) was developed. First, Al(OH) 3 was pretreated by using high-energy dry-milling. This was followed by impregnation with moderately concentrated aqueous Ni-salt solutions with different counter anions under mild conditions. Using this protocol, beside the already known NiAl 4 -LDHs with chloride, nitrate, sulfate interlamellar anions, bromide, iodide, perchlorate and sulfamate ion intercalated versions were also possible to be prepared for the first time. Catalysts obtained from these LDHs proved to be active in CO 2 hydrogenation reaction. The quality of interlayer anions was found to exert a profound effect on the topotactic transformation of LDHs, the in situ reduction of nickel and the formation of spinel-type oxides. Catalysts from sulfate and sulfamate containing NiAl 4 -LDHs possessed outstandingly high (>90 %) CO selectivity independently from the reaction temperatures, while those obtained from nitrate and perchlorate containing LDHs facilitated mostly and robustly the formation of methane. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • <2 nm Pt, Ru and Rh NCs were anchored over CeO 2 /MCF17. • Supported metal NCs exhibited excellent catalytic performance for CO 2 reduction. • Ru NCs/CeO 2 exhibited ∼ 99% selectivity to CH 4. • Effect of two entirely different supports (CeO 2 and MCF 17) was evaluated. Efficient conversion of CO 2 into CH 4 and CO brings an important opportunity to get valuable feedstock for a variety of industrially important reactions as both CH 4 and CO are widely used as starting materials for the synthesis of valuable fuels and chemicals. Herein, we synthesized sub-nanometer (<2nm) Platinum (Pt), Ruthenium (Ru) and Rhodium (Rh) nanoclusters (NCs) via colloidal method; successfully decorated over mesoporous CeO 2 and high surface area (HSA) siliceous meso -cellular foam (MCF 17) and tested for high-pressure CO 2 reduction at lower temperature range (220–340 °C). Pt and Ru NCs exhibited typical reverse water gas shift (RWGS) and methanation catalytic performance respectively with minimal influence of the nature of support however, Rh NCs showed drastic variations in the product selectivity which exhibited strong influence of the support over the product distribution. Furthermore, Ru NCs (with a relatively lower metal loading ∼ 1 wt%) were found to be highly selective to CH 4 (∼99 %) and stable (upto 40 hr time on stream) with either CeO 2 /MCF 17 at 340 °C; also Ru NCs exhibited comparatively the highest CO 2 conversion (∼93 % in case of Ru NCs/CeO 2) among the supported metal NCs. HRTEM results showed that metal NCs were homogeneously dispersed with a controlled and uniform particle size (<2nm); no substantial agglomeration of Ru NCs were observed after reaction. Beside the stable dispersion of NCs, Near Ambient Pressure (NAP) in situ XPS of Ru/CeO 2 showed that the dynamic Ce3+/Ce4+ ratio of CeO 2 can attribute to the high activity and selectivity. [ABSTRACT FROM AUTHOR]

Constructing stable and effective bio-synthesized heterostructure-photocatalyst has been demanding in the advancement of the photocatalysis-field. Herein, bismuth vanadate (BiVO 4) was bio-fabricated using Curcuma longa via hydrolysis route for effective charge separation due to supramolecular-organic-semiconductor system of C. longa. Transmission Electron Microscopy (TEM), High Resolution-Transmission Electron Microscopy (HR-TEM), Surface Assisted Electron Diffraction (SAED), and Electron Impedance Spectroscopy (EIS) reflected successful fabrication of heterojunction between C. longa and BiVO 4. The as-fabricated nanoflowers of C. longa/ BiVO 4 (BVO-G) reflected highly efficient photocatalytic fragmentation of Organochlorine Pesticides (OCPs) [2,4-D (2,4-dichlorophenoxy acetic acid, 90.2%) and 2,4-DP [2-(2,4-dichlorophenoxy propionic acid, 70.52%)] on comparison with pristine BiVO 4 [2,4-D (45.94%) and 2,4-DP (28.18%)] within 120 min of visible-light-irradiation and also showed much better efficiency in comparison with earlier fabricated materials. Further, optical studies including photochemical responses and radical-quenching showed that h+, ·O 2 − and ·OH were responsible for the fragmentation of these recalcitrant herbicides. Based on in-situ High Performance Liquid Chromatography (HPLC) and Liquid Chromatography Mass Spectroscopy (LCMS) analysis, degradation pathways were designed. This work provides an in depth understanding of bio-fabrication of photocatalyst by enhancing the active sites of the reactants and hindering the recombination of photogenerated charge carriers. [Display omitted] • Bismuth vanadate nanoparticles (BVO-G) were bio-fabricated using C. longa. • Heterojunction reduces charge transfer resistance. • Visible-LED source was irradiated for photocatalytic degradation. • 100% MO dye, 90% 2,4-D, and 69.5% 2,4-DP was degraded using BVO-G. • LCMS reflected 90% TOC removal in 2,4-D using BVO-G. [ABSTRACT FROM AUTHOR]

Hybrid materials of electrically conducting polymers and inorganic semiconductors form an exciting class of functional materials. To fully exploit the potential synergies of the hybrid formation, however, sophisticated synthetic methods are required that allow for the fine-tuning of the nanoscale structure of the organic/inorganic interface. Here we present the photocatalytic deposition of a conducting polymer (polyaniline) on the surface of silicon carbide (SiC) nanoparticles. The polymerization is facilitated on the SiC surface, via the oxidation of the monomer molecules by ultraviolet-visible (UV-vis) light irradiation through the photogenerated holes. The synthesized core-shell nanostructures were characterized by UV-vis, Raman, and Fourier Transformed Infrared (FT-IR) Spectroscopy, thermogravimetric analysis, transmission and scanning electron microscopy, and electrochemical methods. It was found that the composition of the hybrids can be varied by simply changing the irradiation time. In addition, we proved the crucial importance of the irradiation wavelength in forming conductive polyaniline, instead of its overoxidized, insulating counterpart. Overall, we conclude that photocatalytic deposition is a promising and versatile approach for the synthesis of conducting polymers with controlled properties on semiconductor surfaces. The presented findings may trigger further studies using photocatalysis as a synthetic strategy to obtain nanoscale hybrid architectures of different semiconductors. [ABSTRACT FROM AUTHOR]

• Effect of nitrogen compounds on nitrogen incorporation into CNTs on various substrates. • "Inverse" effect of temperature on nitrogen incorporation into CNTs. • Effect of hydrogen on the mechanism of nitrogen incorporation into CNTs. • The presence of various N species in CNTs was identified by XPS. • Production of CNTs with bamboo structure by injection method. Nitrogen doping carbon nanotubes can enhance their beneficial physical and chemical properties, rendering them more desirable for various applications, e.g., in electronics. In this study, we used catalytic chemical vapor deposition to synthesize carbon na-no-tube forests on different substrates. The samples were prepared in the presence of compounds containing nitrogen (ammonia, acetonitrile, tripropylamine, and their mixture with acetone) that were introduced into the reactor by bubbling or injection. Of the two different nitrogen introduction methods, the direct injection of a liquid nitrogen precursor promoted the synthesis of bamboo-structured carbon nanotube forests more efficiently. It was found in the injection experiments that the amount of precursor affected the extent of nitrogen incorporation. The presence of various nitrogen species in CNTs was also identified, and the manner in which temperature and the presence of hydrogen both influence nitrogen incorporation into the carbon na-no-tubes was observed. [Display omitted] [ABSTRACT FROM AUTHOR]

In this study, a set of nitrogen-doped TiO-based nanomaterials demonstrating photocatalytic activity was developed by combining the efforts of lattice doping and metal nanoparticle decoration and tested for photo-degradation of methylene blue dye by applying solar simulator irradiation. The surface potential shifts of these TiO-based photocatalytic nanomaterials measured by Kelvin probe force microscope have been used to study the degree of electron generation of the photocatalysts after irradiation and were well correlated with the photocatalytic activity. The nitrogen-doped TiO nanowires decorated with Pt nanoparticles can induce obvious electron accumulation and result in a large shift of surface potential. The analysis shows a clear correlation between the surface potential shift and the photodegradation activity. Furthermore, a thorough comparative photocatalytic activity study combined with X-ray photoelectron spectroscopy analysis of the materials-doped with nitrogen under various conditions-reveals that the photocatalytic efficiency of the catalysts is maintained even if the lattice doping is leached e.g., by thermal treatments after doping. Graphical Abstract: By monitoring the surface potential shifts of various TiO-based photocatalysts by photo-assisted Kelvin probe force microscopy, we obtain a useful tool for developing novel materials with high photocatalytic activity.[Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

[Display omitted] • PtNPs enhance CO 2 methanation activity in mesoporous and commercial Co 3 O 4 differently. • Partial coverage of Co-Pt alloy particles by the Co x O y layer has been postulated. • New basic centres are responsible for the higher enhancement effect of the Pt/c-Co 3 O 4. Based on our previous investigations, it turned out that the Co 3 O 4 material is a promising catalyst in the ambient pressure CO 2 methanation. This work aims at understanding the Pt-Cobalt-Oxide surface interaction and its effect on the catalytic performance. The incorporation of Pt nanoparticles into the mesoporous Co 3 O 4 (Pt/m-Co 3 O 4) and commercial Co 3 O 4 (Pt/c-Co 3 O 4) improves the catalytic activity of both catalysts by a factor of ∼ 1.4 and ∼ 1.9 respectively at 673 K. The same tendency towards the increased basicity was also observed. Morphology-induced surface basicity was previously shown to play a key role in determining the catalytic activity of free-standing supports. From HR-TEM (-EDX), EXAFS, CO 2 -TPD, and CO chemisorption measurements it was established that during the pre-treatment, Co-Pt alloy particles partially covered by the Co x O y layer are formed. It has been postulated that this structure transformation generates new basic centres, the amount of which per unit surface area is significantly larger for Pt/c-Co 3 O 4 and this in turn is responsible for the higher enhancement effect of the Pt/c-Co 3 O 4 catalyst in the CO 2 methanation. This study emphasizes the importance of the surface structure exploration for the dynamic catalytic systems in order to reach maximum activity and selectivity in the CO 2 methanation. [ABSTRACT FROM AUTHOR]

Cadmium (Cd) is a metal used in various industrial applications, thereby causing exposure to Cd-containing fumes. The submicron-sized particles in the fumes represent an extra risk due to their high mobility within the organism and high surface area. Toxicity of Cd on the liver, kidney and bones is well known, but there are less data on its neurotoxicity. Here, male Wistar rats were treated for 3 and 6 weeks by intratracheal instillation of cadmium oxide nanosuspension. The body weight gain in treated rats was significantly decreased, and in the rats treated with high dose (0.4 mg/kg Cd daily), there was a significant increase in the weight of lungs and thymus. In this group, the spectrum of spontaneous cortical electrical activity was shifted to higher frequencies, the latency of sensory-evoked potentials was lengthened, and the frequency following ability of the somatosensory evoked potential was impaired—even without detectable Cd deposition in the brain. The data support the role of the nano-sized Cd in the causation of nervous system damage and show the possibility of modeling human neurotoxic damage in rats. [ABSTRACT FROM AUTHOR]

Context and objective: Lead (Pb) is a heavy metal harmful for human health and environment. From leaded gasoline (still used in certain countries), and in Pb processing and reprocessing industries, airborne particles are emitted which can be inhaled. In such exposure, the size of particles entering the airways is crucial. The nervous system is a primary target for Pb, and consequences like occupational neuropathy and delayed mental development of children are well-known. The aim of this work was to investigate the neurotoxicity of Pb nanoparticles (NPs) applied into the airways of rats. Methods: Nano-sized lead oxide particles (mean diameter ca. 20 nm) were suspended in distilled water and instilled into the trachea of adult male Wistar rats (in doses equivalent to 2 and 4 mg/kg Pb), 5 times a week for 3 and 6 weeks. At the end, open field motility was tested, then central and peripheral nervous activity was recorded in urethane anesthesia. Results and conclusion: The treated rats'' body weight gain was significantly lower than that of the controls from the 3rd week onwards, and the weight of their lungs was significantly increased. Horizontal motility increased while vertical motility decreased. Spontaneous cortical activity was shifted to higher frequencies. The somatosensory cortical evoked potential showed increased latency and decreased frequency-following ability, and similar alterations were seen in the tail nerve. Significant Pb deposition was measured in blood, brain, lung and liver samples of the treated rats. The experiments performed seem to constitute an adequate model of the human effects of inhaled Pb NPs. [ABSTRACT FROM AUTHOR]

Occupational lead exposure occurs mostly by inhalation while the general population can is exposed by ingestion. In the experiment presented, the two exposure routes were modelled in rats using different physicochemical forms of lead. To mimic airborne exposure, PbO nanoparticles (mean diameter ca. 20 nm) were instilled into the trachea of the rats (2 or 4 mg/kg b. w.) five times a week for 6 weeks. In per os treatment, 80 or 320 mg/kg b. w. Pb-acetate was given to the rats by gavage (also five times a week for 6 weeks). To combine the two routes of exposure, rats were treated per os with Pb acetate for 3 weeks, followed by intra-tracheal instillation of Pb-oxide nanoparticles for another 3 weeks, with the same timing and doses as above. After the 3 or 6 weeks of exposure, the effects of lead on the central nervous system of the rats were investigated by behavioural and electrophysiological methods. Both chemical forms and routes of exposure affected differently the outcome of central nervous system investigations. [ABSTRACT FROM AUTHOR]

Nowadays gas detection in the ppm and sub-ppm domain is essential in terms of environmental protection as well as reducing sanitary risks. However, detecting systems to perform these measurements (e.g., gas chromatographs) are expensive and take up too much space, thus their use is not likely to become wide-spread. Small, cheap and easily mountable sensors, such as resistive sensors are more applicable for this purpose. But the main disadvantage of these sensors is the lack of chemical selectivity. Yet, a novel method called fluctuation-enhanced sensing (FES), which considers the sensor noise as the source of chemical information, can be used to improve selectivity. Since carbon nanotube (CNT)-based sensors are regarded as promising devices for FES measurements, we investigated whether stationary fluctuations in output signal (dc-resistance) of a CNT sensor could be used to increase chemical selectivity. In this work we prove that FES is applicable to increase selectivity of CNT sensors: air polluting gases (N2O, NH3 and H2S) and their mixtures can be distinguished. Furthermore, we also show that different concentrations of the same analyte can be differentiated and chemical selectivity can be extended into the sub-ppm region. [ABSTRACT FROM AUTHOR]

Abstract: Double hydroxides of Ba(II) and Fe(III) were prepared by the co-precipitation method. Co-precipitation was facilitated by applying highly alkaline, carbonate free NaOH solutions with varying base concentrations (2−20M). The substances, thus obtained, were characterised by thermal methods, XRD spectra of samples treated at various temperatures, Mössbauer and X-ray absorption spectroscopies. It was found that in extremely concentrated base solutions (≥10M) layered double hydroxides, most probably with intercalated OH− ions, were formed, indeed, while at low base concentration the Fe(III) ions were precipitated as various oxyhydroxides and the Ba(II) ions remained dissolved. [Copyright &y& Elsevier]

Abstract: Conducting polymer-based magnetic composites with controlled magnetic behaviour have been synthesized by chemical polymerization in nanoparticle containing organic media. Poly(3-thiophene-acetic-acid)–Fe3O4 hybrids have been prepared with five different iron-oxide contents, up to 20m/m%, according to the results obtained by thermogravimetric analysis (TGA) and inductively coupled plasma atomic emission spectroscopic (ICP-AES) measurements. X-ray diffraction (XRD) and Mössbauer spectroscopic results gave direct evidences for the incorporation of both maghemite and magnetite. Photoacoustic Fourier transform infrared spectroscopic (PAS-FT-IR) measurements showed a chemical interaction between the polymer and the iron-oxide particles. SQUID investigations indicated a typical superparamagnetic behaviour for all samples, where saturation magnetization values proved to be tunable by the Fe3O4 content. After coating them onto electrode surfaces, basic electrochemical activity of the composite samples was demonstrated by cyclic voltammetry. [Copyright &y& Elsevier]

The synthesis of the copper-poor and aluminum-rich layered double hydroxides (LDHs) of the CuAl4 type was optimized in detail in this work, by applying an intense mechanochemical treatment to activate the gibbsite starting reagent. The phase-pure forms of these LDHs were prepared for the first time; using copper nitrate and perchlorate salts during the syntheses turned out to be the key to avoiding the formation of copper hydroxide sideproducts. Based on the use of the optimized syntheses parameters, the preparation of layered triple and multiple hydroxides was also attempted using Ni(II), Co(II), Zn(II) and even Mg(II) ions. These studies let us identify the relative positions of the incorporating cations in the well-known selectivity series as Ni2+ >> Cu2+ >> Zn2+ > Co2+ >> Mg2+. The solids formed were characterized by using powder X-ray diffractometry, UV–Vis diffuse reflectance spectroscopy, Fourier-transform infrared spectroscopy, thermogravimetric analysis and scanning electron microscopy. The catalytic potential of the samples was investigated in carbon monoxide oxidation reactions at atmospheric pressure, supported by an in situ diffuse reflectance infrared spectroscopy probe. All solids proved to be active and the combination of the nickel and cobalt incorporation (which resulted in a NiCoAl8 layered triple hydroxide) brought outstanding benefits regarding low-temperature oxidation and increased carbon monoxide conversion values. [ABSTRACT FROM AUTHOR]