scholarly journals Development of palladium catalysts modified by ruthenium and molybdenum as anode in direct ethanol fuel cell

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Yonis Fornazier Filho ◽  
Ana Caroliny Carvalho da Cruz ◽  
Rolando Pedicini ◽  
José Ricardo Cezar Salgado ◽  
Priscilla Paiva Luz ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Palladium Catalysts ◽  
Carbon Support ◽  
X Ray Diffraction ◽  
Direct Ethanol Fuel Cell ◽  
Pd Catalysts ◽  
Bifunctional Mechanism ◽  
Catalytic Activities ◽  
Intrinsic Mechanism ◽  
Ternary Catalysts

AbstractPhysical and electrochemical properties of Pd catalysts combined with Ru and Mo on carbon support were investigated. To this end, Pd, Pd1.3Ru1.0, Pd3.2Ru1.3Mo1.0 and Pd1.5Ru0.8Mo1.0 were synthesized on Carbon Vulcan XC72 support by the method of thermal decomposition of polymeric precursors and then physically and electrochemically characterized. The highest reaction yields are obtained for Pd3.2Ru1.3Mo1.0/C and Pd1.5Ru0.8Mo1.0/C and, as demonstrated by thermal analysis, they also show the smallest metal/carbon ratio compared the other catalysts. XRD (X-ray Diffraction) and Raman analyses show the presence of PdO and RuO2 for the Pd/C and the Pd1.3Ru1.0/C catalysts, respectively, a fact not observed for the Pd3.2Ru1.3 Mo1.0 /C and the Pd1.5Ru0.8Mo1.0/C catalysts. The catalytic activities were tested for the ethanol oxidation in alkaline medium. Cyclic voltammetry (CV) shows Pd1.3Ru1.0/C exhibiting the highest peak of current density, followed by Pd3.2Ru1.3Mo1.0/C, Pd1.5Ru0.8Mo1.0/C and Pd/C. From, chronoamperometry (CA), it is possible to observe the lowest rate of poisoning for the Pd1.3Ru1.0/C, followed by Pd3.2Ru1.3Mo1.0/C, Pd1.5Ru0.8Mo1.0/C and Pd/C. These results suggested that catalytic activity of the binary and the ternary catalysts are improved in comparison with Pd/C. The presence of RuO2 activated the bifunctional mechanism and improved the catalytic activity in the Pd1.3Ru1.0/C catalyst. The addition of Mo in the catalysts enhanced the catalytic activity by the intrinsic mechanism, suggesting a synergistic effect between metals. In summary, we suggest that it is possible to synthesize ternary PdRuMo catalysts supported on Carbon Vulcan XC72, resulting in materials with lower poisoning rates and lower costs than Pd/C. Graphic abstract

A graphdiyne-based carbon material for electroless deposition and stabilization of sub-nanometric Pd catalysts with extremely high catalytic activity

2019 ◽  
Vol 7 (21) ◽  
pp. 13142-13148 ◽  
Author(s):  
Liang-Liang Yang ◽  
Hong-Juan Wang ◽  
Juan Wang ◽  
Yu Li ◽  
Wen Zhang ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Carbon Material ◽  
Electroless Deposition ◽  
Suzuki Coupling ◽  
High Catalytic Activity ◽  
Coupling Reactions ◽  
Pd Catalysts ◽  
Catalytic Activities

A new graphdiyne-based carbon material was synthesized as an ideal substrate for electroless deposition and stabilization of sub-nanometric Pd catalysts, which showed extremely high catalytic activities for the reduction of nitroarenes and Suzuki coupling reactions.

scholarly journals Synthesis of porous LaFeO3 prepared by nanocasting method for photo-Fenton degradation of oily-containing wastewater

2021 ◽  
Vol 11 (1) ◽  
pp. xx-xx
Author(s):  
Nga Phan To ◽  
Lien Nguyen Hong ◽  
Tuyen Le Van ◽  
Nhan Phan Chi ◽  
Huyen Phan Thanh
Keyword(s):  
Electron Microscopy ◽  
Catalytic Activity ◽  
Visible Light ◽  
Diffuse Reflectance Spectroscopy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Catalytic Activities ◽  
Transmission Electron ◽  
Visible Light Driven ◽  
Adsorption Desorption

Porous LaFeO3 were synthesised by nanocasting method using mesoporous silica (SBA-15) as a hard template and used as a visible-light-driven photocatalyst. The as-synthesised LaFeO3 photocatalyst were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray Diffraction (XRD), N2 adsorption-desorption, and Ultraviolet–Visible Diffuse Reflectance Spectroscopy (UV-vis DRS). The photo-Fenton catalytic activities of porous LaFeO3 were investigated for the degradation of oily-containing wastewater. The results showed that porous LaFeO3 had better photo-Fenton catalytic activity under visilbe light irradiation than pure LaFeO3. The remarkable improvement photo-Fenton catalytic activity of porous LaFeO3 material could be attributed to the synergistic effect of adsorption and visible light photo-Fenton processes thanks to its porous structure.

scholarly journals Crystal Structure and Catalytic Activity of Poly[bis(3-bromo-2-hydroxybenzaldehyde)-2-aminopyrimidinemagnesium(II)] for Hydrogenation of 1,3-Butadiene

2021 ◽  
Vol 16 (2) ◽  
pp. 260-266
Author(s):  
Li-Hua Wang ◽  
Fan-Yuan Kong ◽  
Xi-Shi Tai
Keyword(s):  
Catalytic Activity ◽  
Coordination Polymer ◽  
X Ray Diffraction ◽  
Acetate Dihydrate ◽  
X Ray ◽  
Catalytic Activities ◽  
Distorted Octahedral Coordination Geometry ◽  
Distorted Octahedral ◽  
Good Catalytic Activity ◽  
Open Access Article

A new six-coordinated Mn(II) coordination polymer, [Mn(L1)(L2)2]n (L1 = 2-aminopyrimidine, HL2 = 3-bromo-2-hydroxybenzaldehyde) was synthesized by 3-bromo-2-hydroxybenzaldehyde, NaOH, 2-aminopyrimidine and manganese(II) acetate dihydrate. The Mn(II) coordination polymer was structural characterized by elemental analysis and single crystal X-ray diffraction. The results show that each Mn(II) ion is six-coordinated with two phenolic hydroxyl O atoms from two 3-bromo-2-hydroxybenzaldehyde ligands (O1 and O4), two formyl group O atoms from two 3-bromo-2-hydroxybenzaldehyde ligands (O2 and O3), and two N atoms from two 2-aminopyrimidine molecules (N1A and N2), and forms a distorted octahedral coordination geometry. The Mn(II) coordination polymer displays a 1D chained structure by the bridge effect of 2-aminopyrimidine N atoms. The catalytic activities of Mn(II) coordination polymer and Pd@Mn(II) coordination polymer for hydrogenation of 1,3-butadiene have been investigated. The Pd@Mn(II) coordination polymer catalyst shows the good catalytic activity and selectivity in  the hydrogenation of 1,3-butadiene. The 1,3-butadiene conversion is 61.3% at 70 °C, and the selectivity to total butene is close to 100%. Copyright © 2021 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0). 

scholarly journals Fe(III) Complexes in Cyclohexane Oxidation: Comparison of Catalytic Activities under Different Energy Stimuli

Catalysts ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1175
Author(s):  
Tannistha Roy Barman ◽  
Manas Sutradhar ◽  
Elisabete C. B. A. Alegria ◽  
Maria de Fátima C. Guedes da Silva ◽  
Armando J. L. Pombeiro
Keyword(s):  
Catalytic Activity ◽  
Product Yield ◽  
Conventional Heating ◽  
Ionization Mass ◽  
X Ray Diffraction ◽  
X Ray ◽  
Catalytic Activities ◽  
Total Product ◽  
Physicochemical Methods ◽  
Catalytic Performances

In this study, the mononuclear Fe(III) complex [Fe(HL)(NO3)(H2O)2]NO3 (1) derived from Nʹ-acetylpyrazine-2-carbohydrazide (H2L) was synthesized and characterized by several physicochemical methods, e.g., elemental analysis, infrared (IR) spectroscopy, electrospray ionization mass spectrometry (ESI-MS), and single crystal X-ray diffraction analysis. The catalytic performances of 1 and the previously reported complexes [Fe(HL)Cl2] (2) and [Fe(HL)Cl(μ-OMe)]2 (3) towards the peroxidative oxidation of cyclohexane under three different energy stimuli (microwave irradiation, ultrasound, and conventional heating) were compared. 1-3 displayed homogeneous catalytic activity, leading to the formation of cyclohexanol and cyclohexanone as final products, with a high selectivity for the alcohol (up to 95%). Complex 1 exhibited the highest catalytic activity, with a total product yield of 38% (cyclohexanol + cyclohexanone) under optimized microwave-assisted conditions.

Use of Carbon Nanomaterials as a Catalyst Support in Fuel Cells

2016 ◽  
Vol 879 ◽  
pp. 1882-1888
Author(s):  
Yoshiyuki Suda
Keyword(s):  
Catalytic Activity ◽  
Carbon Nanomaterials ◽  
Reduction Method ◽  
Catalyst Support ◽  
X Ray Diffraction ◽  
X Ray ◽  
Catalytic Activities ◽  
Transmission Electron ◽  
Ptru Catalyst ◽  
Different Shapes

PtRu or Pt catalysts were supported on four types of carbon nanomaterials with different shapes, sizes, and graphitic and electrical properties, and their resulting catalytic activities were evaluated by electrochemical methods. The carbon nanomaterials used included two types of particles: Arc Black (AcB) and Vulcan XC-72R (Vulcan), and two types of nanofibers: carbon nanocoils (CNC) and VGCF-X. Pt and Ru were loaded onto the nanomaterials by a reduction method using sodium borohydride. Transmission electron microscopy and X-ray diffraction (XRD) revealed the PtRu catalyst particles to be 4–6 nm in diameters. The shifts in the Pt (111) XRD peaks of the catalysts on CNC and VGCF-X were larger than those on AcB and Vulcan, indicating a higher degree of alloying between Pt and Ru. The diameters of the CNC-supported Pt and PtRu catalyst particles had the narrowest distributions and were constant within the range of catalyst loadings investigated. Electrochemical studies of the catalysts during methanol oxidation were carried out using cyclic voltammetry. The catalyst particles supported on CNC and VGCF-X exhibited higher catalytic activity than those on AcB and Vulcan. The effect of the surface area of the carbon nanomaterials on the catalytic activity is discussed.

scholarly journals Enhancement of both optical and catalytic activity of copper-decorated porous silicon micro-particles

2021 ◽  
Vol 93 (3) ◽  
pp. 30402
Author(s):  
Abderrahmane Hamdi ◽  
Chohdi Amri ◽  
Rachid Ouertani ◽  
Elhadj Dogheche ◽  
Hatem Ezzaouia
Keyword(s):  
Catalytic Activity ◽  
Chemical Vapour ◽  
Catalytic Performance ◽  
Photoluminescence Properties ◽  
X Ray Diffraction ◽  
X Ray ◽  
Catalytic Activities ◽  
Micro Particles ◽  
Good Crystallinity ◽  
Short Times

To the best of our knowledge, this study is the first to investigate the effect of chemical vapour etching (CVE) combined with copper decoration on both the optical and catalytic activities of silicon micro-particles (SiμPs). After exposure to acid vapours emanating from a hot solution of hydrogen fluoride/nitric acid (HF/HNO3), scanning electron microscope images of the treated powder show the formation of a porous, sponge-like structure on the sidewalls of SiμPs. Fourier transmission infra-red analysis shows the appearance of hydride bonds related to the formation of the porous structure. X-ray diffraction measurements and Raman spectroscopy show the good crystallinity of the samples. The strong photoluminescence properties of the obtained porous SiμPs (pSiμPs) reveal that the vapour etching process generated silicon nanocrystals within these particles. In this work, we have investigated the catalytic activity of copper nanoparticles (CuNPs) loaded on the surface of pSiμPs, in order to reduce the toxic compound 4-nitrophenol to 4-aminophenol. The results show excellent catalytic performance in very short times (less than 1 min).

Photocatalytic activity of TiO2 synthesized by anodization and anodic spark deposition

MRS Advances ◽  
2020 ◽  
Vol 5 (61) ◽  
pp. 3141-3152
Author(s):  
Alma C. Chávez-Mejía ◽  
Génesis Villegas-Suárez ◽  
Paloma I. Zaragoza-Sánchez ◽  
Rafael Magaña-López ◽  
Julio C. Morales-Mejía ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Photocatalytic Activity ◽  
Surface Characteristics ◽  
Amorphous Solids ◽  
X Ray Diffraction ◽  
X Ray ◽  
Catalytic Activities ◽  
Anodic Spark Oxidation ◽  
Porous Surfaces ◽  
Scanning Electron

AbstractSeveral photocatalysts, based on titanium dioxide, were synthesized by spark anodization techniques and anodic spark oxidation. Photocatalytic activity was determined by methylene blue oxidation and the catalytic activities of the catalysts were evaluated after 70 hours of reaction. Scanning Electron Microscopy and X Ray Diffraction analysis were used to characterize the catalysts. The photocatalyst prepared with a solution of sulfuric acid and 100 V presented the best performance in terms of oxidation of the dye (62%). The electric potential during the synthesis (10 V, low potential; 100 V, high potential) affected the surface characteristics: under low potential, catalyst presented smooth and homogeneous surfaces with spots (high TiO2 concentration) of amorphous solids; under low potential, catalyst presented porous surfaces with crystalline solids homogeneously distributed.

Model reactions for the study of hydrogenation and acidic activity of palladium catalysts

1987 ◽  
Vol 52 (8) ◽  
pp. 2019-2027 ◽  
Author(s):  
Libor Červený ◽  
Nguyen Thi Du ◽  
Ivo Paseka
Keyword(s):  
Palladium Catalysts ◽  
Styrene Oxide ◽  
Side Reactions ◽  
Pd Catalysts ◽  
Variable Parameters ◽  
Acid Properties ◽  
Liquid Phase Hydrogenation ◽  
Acid Catalysed Reactions ◽  
Different Content ◽  
Model Reactions

Palladium catalysts have been used to study the hydrogenation of 1-phenyl-2-butene-1-ol which is accompanied by several side reactions considered to be acid-catalysed. Another model reaction studied was dehydration and subsequent hydrogenation or hydrogenolysis of 1-phenyl-1,3-propanediol to 3-phenyl-1-propanol, accompanied by formation of propylbenzene. The dehydration and propylbenzene formation can be again classified as acid-catalysed reactions. Another one is methanolysis of styrene oxide taking place under conditions of liquid phase hydrogenation due to the acid properties of Pd-H systems. Hydrogenation activity of Pd catalysts was tested by hydrogenation of cyclohexene. Sixteen Pd catalysts on different supports and with different content of active component were used, their activity and selectivity was determined and the effect of variable parameters in the synthesis of these catalysts on the activity and selectivity is discussed.

Bis(μ-carboxylato)dienerhodium(I) Complexes - Synthesis, Characterization and Catalytic Activity

2008 ◽  
Vol 73 (8-9) ◽  
pp. 1205-1221 ◽  
Author(s):  
Jiří Zedník ◽  
Jan Sedláček ◽  
Jan Svoboda ◽  
Jiří Vohlídal ◽  
Dmitrij Bondarev ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Diffraction Analysis ◽  
Spectroscopic Methods ◽  
X Ray Diffraction ◽  
X Ray

Dinuclear rhodium(I) η2:η2-cycloocta-1,5-diene (series a) and η2:η2-norborna-2,5-diene (series b) complexes with μ-RCOO- ligands, where R is linear C21H43 (complexes 1a, 1b), CH2CMe3 (2a, 2b), 1-adamantyl (3a, 3b) and benzyl (4a, 4b), have been prepared and characterized by spectroscopic methods. Structures of complexes 2b, 3a and 4a were determined by X-ray diffraction analysis. Complexes prepared show low to moderate catalytic activity in polymerization of phenylacetylene in THF giving high-cis-transoid polymers, but they show only oligomerization activity in dichloromethane.

scholarly journals Catalytic Activity of Beta-Cyclodextrin-Gold Nanoparticles Network in Hydrogen Evolution Reaction

Catalysts ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 118
Author(s):  
Qui Quach ◽  
Erik Biehler ◽  
Ahmed Elzamzami ◽  
Clay Huff ◽  
Julia M. Long ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Catalytic Activity ◽  
Gold Catalyst ◽  
Hydrogen Gas ◽  
Hydrolysis Reaction ◽  
X Ray Diffraction ◽  
Beta Cyclodextrin ◽  
Transmission Electron ◽  
Production Of Hydrogen ◽  
Climate Crisis

The current climate crisis warrants investigation into alternative fuel sources. The hydrolysis reaction of an aqueous hydride precursor, and the subsequent production of hydrogen gas, prove to be a viable option. A network of beta-cyclodextrin capped gold nanoparticles (BCD-AuNP) was synthesized and subsequently characterized by Powder X-Ray Diffraction (P-XRD), Fourier Transform Infrared (FTIR), Transmission Electron Microscopy (TEM), and Ultraviolet-Visible Spectroscopy (UV-VIS) to confirm the presence of gold nanoparticles as well as their size of approximately 8 nm. The catalytic activity of the nanoparticles was tested in the hydrolysis reaction of sodium borohydride. The gold catalyst performed best at 303 K producing 1.377 mL min−1 mLcat−1 of hydrogen. The activation energy of the catalyst was calculated to be 54.7 kJ/mol. The catalyst resisted degradation in reusability trials, continuing to produce hydrogen gas in up to five trials.

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