We explored the impact of synthesis methods on the physicochemical properties and catalytic performance of Ni/ CeO2 catalysts for ethanol steam reforming (ESR). Sputtering (SP) deposition and incipient wetness impregnation (IWI) were employed to prepare the catalysts; detailed characterizations, including HRTEM, XPS, Raman spec-troscopy, and TPR analyses, revealed that the Ni/CeO2-SP catalyst exhibits a more uniform Ni nanoparticle distribution, stronger metal-support interactions, and more oxygen vacancies. The Ni/CeO2-SP catalyst demonstrated superior catalytic performance, with a hydrogen production rate of 8.1 L.h1.gcat1 (672 L.h1. gmetal1). Such results are superior to the observed in the literature, which can be related to the highly uniform Ni dispersion and low metal loading (1.0 wt%). Additionally, the synthesis method affected the type of coke deposition, which was also attested by theoretical calculation insights regarding their mechanism formation. Finally, we also observed differences in oxygen vacancy creation, indicating that the SP deposition method provides a more effective strateg

The reduction of atmospheric CO2 is indeed a major challenge for modern life due to its increase as a result of the intensified contemporary industrial activities and its contribution to global warming. One of the most desirable approaches to accomplish this goal is to convert CO2 into C1 feedstocks, such as formic acid (FA). In this regard, naked ruthenium clusters and nanoparticles (1.8 +/- 0.3 nm) are prepared by magnetron sputtering into different supported ionic liquid phases (SILPs) that demonstrated remarkable efficiency in producing a total of 2.2 M of free FA with a TONs of 7305 in 1-Butyl-3-methylimidazolium acetate ionic liquid media at 87 degrees C. The higher efficiently is related to the hydrophobic/hydrophilic effect presents in the ionic liquid-cages of the SILPs akin to the micelle nano (micro)reactors, which act as catalytic membranes enabling the tuning of FA production. DFT calculations support the mechanistic approach followed the hydrogenation of HCO3* to FA.

The indirect conversion of CO2 into glycerol carbonate using DMC was investigated using pristine sodium titanate nanotubes (NaTNT) and nanostructured titanates (calcined NaTNT at different temperatures) as catalysts. The calcination changes the morphology of the nanostructured titanates, between 200 and 400 degrees C the nanotubes shape is retained, however above these temperatures (500 and 600 degrees C) nanoribbons were identified, as well as nanorods obtained at 700 degrees C. A significant decrease in specific surface area and total pore size in temperatures up 500 degrees C was also observed. Furthermore, a decrease in the Ti+4/Ti+2 ratio and in the binding energy of Ti 2p(3/2) and Ti 2p(1/2) were observed, indicating an increase in the electron density and consequently increase in the Lewis acidity character of the titanium atom. All the nanostructured titanates showed good catalytic activity with glycerol conversion and GC selectivity above 90%. The results of the recycling showed that the nanostructured catalysts retained a good catalytic activity with high glycerol conversion (> 90%) although the GC selectivity decreased due the formation of glycidol, a high value-added by-product. (c) 2023 Institution of Chemical Engineers. Published by Elsevier Ltd. All rights reserved.

We report a photocatalytic device based on gold nanoparticles (AuNPs/TiO2) coated with an ionic liquid (IL) as a very active, stable, and versatile system for hydrogen evolution re-actions (HERs) via methanol photo reforming (MPR) and photocatalytic water-splitting (WSR) reaction. The devices prepared by magnetron sputtering yield hybrid materials with direct Au-TiO2 interactions that were subsequently coated with BMIm.NTf2 (IL@Au@TiO2). The IL presence critically enhances the photocatalytic performance given its interaction with the AuNPs and TiO2 surfaces by decreasing the flat band energy levels and the Schottky barrier thickness. The results show an increase in the number of charge carriers yielding a capacitor-like effect generated by interactions of IL and Au@TiO2 par-ticles. Apparent quantum yield (AQY) up to 28.3% under UV irradiation (365 nm) and 22.9% at 405 nm irradiation were observed in the HER employing the as-prepared materials.(c) 2023 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

We report a photocatalytic device based on gold nanoparticles (AuNPs/TiO2) coated with an ionic liquid (IL) as a very active, stable, and versatile system for hydrogen evolution reactions (HERs) via methanol photo reforming (MPR) and photocatalytic water-splitting (WSR) reaction. The devices prepared by magnetron sputtering yields hybrid materials with direct Au-TiO2 interactions that were subsequently coated with IL without significant disturbance (IL@Au@TiO2). The IL presence critically enhances the photocatalytic performance given its interaction with the AuNPs and TiO2 surfaces by decreasing the flat band energy levels and the Schottky barrier thickness. The results show an increase in the number of charge carriers yielding a capacitor-like effect generated by interactions of IL and Au@TiO2 particles. Apparent quantum yield (AQY) up to 28.3 % under UV irradiation (365 nm) and 22.9 % at 405 nm irradiation were observed in the HER employing the as-prepared materials

This work illustrates an effective method for obtaining hybrid nanoparticles of Ni-Fe-Mo permalloy and reduced graphene oxide (rGO). The metallic nanoparticles were spread by the sputtering technique, which allowed a good dispersion of the metallic nanoparticles onto rGO substrate powder. TEM showed permalloy nanoparticles smaller than 8 nm uniformly distributed throughout rGO. Permalloy/rGO hybrid with 10.5 wt% loading of permalloy nanoparticles was calculated by TGA. RBS experiment reveals that permalloy target and the nanoparticles deposited have similar composition. The interaction between permalloy and rGO was studied by FT-IR. Ni-Fe-Mo/rGO presented an electrical conductivity of 122 Scm(-1), significantly higher than the original rGO and a magnetization hysteresis-loop coercivity of 16 Oe at room temperature. To our knowledge this is the first work in which permalloy nanoparticles are deposited onto graphene powder substrate by a physical impregnation technique.

H2 activation proceeds via homolytic activation over AuNPs confined in ionic liquid hybrid supports and display high kinetic isotope effects and convex curves in the Arrhenius plots, which suggests the possible involvement of a tunneling pathway.

A simple method based on sputtering deposition of Pd onto mesoporous SiO2 (SBA-15) was employed to produce supported Pd nanoparticles (NPs) that can be used as hydrogenation catalysts. The use of sputtering deposition eliminates contaminants and avoids additional drawbacks of traditional chemical methods applied to prepare heterogeneous supported metal catalysts. A mechanical resonant stirrer was used to revolve the SBA-15 powder and ensure homogeneous distribution of the Pd NPs over the support. The SBA-15 pores act as templates for Pd NPs and drive nanostructure growth. Consequently, the NPs obtained have the same diameter as that of the SBA-15 channels (~5 nm) and elongated particles are formed as sputtering deposition increases. The SBA-15 supported Pd NPs (Pd NPs/SBA-15) were tested in a probe hydrogenation of cyclohexene reaction to evaluate the catalytic activity of the Pd NPs. Turnover frequency (TOF) of 2000 min-1 were achieved with the lower Pd NPs concentration (0.15 wt%) catalyst.

The use of metal/oxide nanoparticles (NPs) as cocatalysts in heterogeneous photocatalysis is an important strategy to improve the photocatalytic activity of semiconductors for hydrogen generation. This article reports the use of a modified sputtering deposition method to prepare ultrafine NiO NPs cocatalysts dispersed on anodic Ta2O5 nanotubes (NTs). In situ X-ray absorption near-edge spectroscopy (XANES) measurements revealed that after exposing the as-prepared Ni NPs to air atmosphere a mixture of 68% of Ni and 32% of NiO was formed. Pure phase NiO NPs was successfully obtained after a controlled thermal oxidation at 500 degrees C which was confirmed by in situ XANES and ex situ XPS analyses. The photocatalytic hydrogen production activity was evaluated using ethanol as a sacrificial agent. Ta2O5 NTs with 0.16 wt % of NiO showed superior photocatalytic activity (up to 7.7 +/- 0.3 mmol h(-1) g(-1)) as compared to pure Ta2O5 NTs (4.9 +/- 0.3 mmol h(-1) g(-1).) The observed higher photocatalytic activity suggests that NiO/Ta2O5 NTs is a promising material for photocatalytic hydrogen evolution.

The magnetron-sputtering approach was used for the deposition of small (ca. 3.7 nm) and uniformly distributed Pd(0)-fcc nanoparticles (Pd-NPs) with partially oxidised surfaces on commercially available carbon black. The pores of the support were uniformly filled by Pd-NPs, and the surface area was drastically reduced by blockage of the pores. The metal concentration increases with the augmentation of the sputtering time without changing the metal NP size. These Pd-nanocatalysts are high efficient for the hydrogenation of nitrobenzene to aniline (TOF up to 141.7 min(-1)), 1,3-cyclohexadiene to cyclohexene (TOF up to 24.0 s(-1)), and cyclohexene to cyclohexane (TOF up to 35.1 s(-1)) under 4 bar of dihydrogen (H-2) at mild temperatures (75-90 degrees C). The magnetron sputtering is one of the simplest, reliable, fast, clean and cheap methods for the preparation of Pd/C catalysts. (C) 2016 Elsevier Ltd. All rights reserved.

Gold nanoparticles (AuNPs) display distinct characteristics as hydrogenation catalysts, with higher selectivity and lower catalytic activity than group 8-10 metals. The ability of AuNPs to chemisorb/activate simple molecules is limited by the low coordination number of the surface sites. Understanding the distinct pathways involved in the hydrogenation reactions promoted by supported AuNPs is crucial for broadening their potential catalytic applications. In this study, we demonstrate that the mechanism of the hydrogenation reactions catalyzed by AuNPs with "clean" surfaces may proceed via homolytic or heterolytic hydrogen activation depending on the nature of the support. The synthesis of naked AuNPs employing gamma-Al2O3 and ionic liquid (IL)-hybrid gamma-Al2O3 supports was accomplished by sputtering deposition using ultrapure gold foils. This highly reproducible and straightforward procedure furnishes small (similar to 6.6 nm) and well-distributed metallic gold nanoparticles (Au(0)NPs) that are found to be active catalysts for the partial and selective hydrogenation of substituted conjugated dienes, alkynes, and alpha,beta-unsaturated carbonyl compounds (aldehydes and ketones). Kinetic and deuterium labeling studies indicate that heterolytic hydrogen activation is the primary pathway occurring on the AuNPs imprinted directly on gamma-Al2O3. In contrast, AuNPs supported on IL-hybrid gamma-Al2O3 materials cause the reaction to proceed via a homolytic hydrogen activation pathway. The IL layer surrounds the AuNPs and acts as a cage, influencing the frequency of the interaction of the catalytically active species and the metal surface and, consequently, the catalytic performance of the AuNPs. The IL layer is shown to improve the product selectivity by the enhancement of the substrate/product discrimination, and to decrease the catalytic activity by shifting the rate-determining step to the H-2 and substrate competitive adsorption/activation on the same active sites. A series of kinetic experiments suggest that AuNPs imprinted on an IL-hybrid gamma-Al2O3 support are more efficient (lower activation energy, E-a) than group 8-10 metal based catalysts for hydrogenation reactions at moderate to high temperatures (75-150 degrees C).

Os geradores eletricos de inducao sao utilizados nas mais diversas areas, como uma alternativa de geracao de energia. Tendo como principal caracteristica o baixo custo de manutencao e facilidade de construcao. Essa alternativa de geracao de energia tem como embasamento o principio da inducao magnetica de Michael Faraday. Utilizando materiais eletricos descartados e de facil aquisicao, construiu-se a plataforma de ensino de baixo custo. Foram analisadas as respostas do sistema obtidas atraves das configuracoes em serie e paralelo. Normal 0 21 false false false PT-BR JA X-NONE

The reaction of BMI·Cl or DMI·Cl with TaCl5affords imidazolium tantalate ionic liquids BMI·TaCl61and DMI·TaCl62, precursors for the synthesis of Ta2O5nanoparticles.

Copper catalysts are very promising, affordable alternatives for noble metals in CO oxidation; however, the nature of the active species remains unclear and differs throughout previous reports. Here, we report the preparation of 8 nm copper nanoparticles (Cu NPs), with high metallic content, directly deposited onto the surface of silica nanopowders by magnetron sputtering deposition. The as-prepared Cu/SiO2 contains 85% Cu0 and 15% Cu2+ and was enriched in the Cu0 phase by H2 soft pretreatment (96% Cu0 and 4% Cu2+) or further oxidized after treatment with O2 (33% Cu0 and 67% Cu2+). These catalysts were studied in the catalytic oxidation of CO under dry and humid conditions. Higher activity was observed for the sample previously reduced with H2, suggesting that the presence of Cu-metal species enhances CO oxidation performance. Inversely, a poorer performance was observed for the sample previously oxidized with O2. The presence of water vapor caused only a small increase in the temperature require for the reaction to reach 100% conversion. Under dry conditions, the Cu NP catalyst was able to maintain full conversion for up to 45 h at 350 °C, but it deactivated with time on stream in the presence of water vapor.

The development of active and stable catalysts has emerged as an important strategy in the catalytic abatement of CO. This article reports the use of the novel Pt-based catalyst supported on crystalline Ta2O5 nanotubes prepared by sputtering and anodization methods in CO oxidation reaction. Crystalline and amorphous Ta2O5 NTs and Pt modified sample were found active in low temperature CO oxidation. Results showed that active and highly stable Pt/Ta2O5 NTs catalyst could be a promising system for CO removal from gas exhaust.

This article reports a new method to cover powder substrates with metallic nanoparticles (NPs) via an electro-magnetic vibrational device adapted to magnetron sputtering equipment. In the present work, it is presented the deposition of Cu, Au, Ni and Pd over three different substrates, Al2O3, SBA15 and Lipase, each one with particular parameters. The size and homogeneity of the NPs deposited with this new method were been measured by several technics as TEM, HRTEM, SEM, AFM and EDS and confirmed the efficiency of the process. Applications on the production of catalyzers, fuel cells, gas sensors and ionic liquids based on NPs can be explored with this technic.

Hybrid organosilicas prepared by sol-gel processes using 1-n-butyl-3-(3-trimethoxysilylpropyl)-imidazolium cations associated with hydrophilic and hydrophobic anions can be easily decorated with well dispersed and similar size (1.8-2.1 nm) Pd nanoparticles (Pd-NPs) by simple sputtering-deposition. Higher Pd concentration at the surface compared to the deeper region is obtained in the supports with smaller pore diameter (containing hydrophobic ILs) than in supports with the largest pore diameter (containing hydrophilic ILs). The IL hydrophobicity plays a central role in the hydrogenation of dienes by controlling the diene access to NP surface active sites.

Well-distributed Ru nanoparticles (Ru-NPs) were produced over Al(2)O(3) supports modified with covalently anchored imidazolium ionic liquids (ILs) containing different anions and cation lateral alkyl chain lengths by simple sputtering from a Ru foil. These Ru-NPs were active catalysts for the hydrogenation of benzene. Furthermore, depending on the nature of the IL used to modify the support (hydrophilic or hydrophobic), different catalytic behaviours were observed. Turnover numbers (TON) as high as 27 000 with a turnover frequency (TOF) of 2.73 s(-1) were achieved with Ru-NPs of 6.4 nm supported in Al(2)O(3) modified with an IL containing the N(SO(2)CF(3))2(-) anion, whereas higher initial cyclohexene selectivities (ca. 20% at 1% benzene conversion) were attained for Ru-NPs of 6.6 nm in the case where Cl(-) and BF(4)(-) anions were used. Such observations strongly suggest that thin layers of ILs surround the NP surface, modifying the reactivity of these catalytic systems. These findings open a new window of opportunity in the development of size-controlled Ru-NPs with tuneable reactivity.

A simple one-step method based on the sputtering deposition of Ni nanoparticles (NP) has been developed for the production of magnetic biocatalysts, avoiding the complications and drawbacks of methods based on chemical functionalisation or coating of magnetic NP. This new technique provided high levels of recovery, reusability and catalytic activity for the lipase-Ni biocatalyst.