scholarly journals Fine-tuning the catalytic activity by applying nitrogen-doped carbon nanotubes as catalyst supports for the hydrogenation of olefins

2019 ◽  
Vol 129 (1) ◽  
pp. 95-106 ◽  
Author(s):  
Emőke Sikora ◽  
Adrienn Kiss ◽  
Zsuzsa H. Göndör ◽  
Péter Pekker ◽  
Ferenc Kristály ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Catalytic Activity ◽  
Metal Binding ◽  
Catalyst Support ◽  
Supported Catalyst ◽  
Hydrogenation Reaction ◽  
Fine Tuning ◽  
Multi Wall Carbon Nanotubes ◽  
Support Materials ◽  
Liquid Phase Hydrogenation

AbstractNitrogen-free multi-wall carbon nanotubes (MWCNTs) and N-doped bamboo-like carbon nanotubes (BCNTs) were synthesized by using catalytic vapor deposition (CVD) and used as catalyst support materials. Pd, Rh, Ru, and Ir have been deposited onto the nanotubes to achieve metal/nanotube catalysts. The catalytic activity of the samples was fine-tuned by changing the type of support. BCNT supported Pd and Rh (Pd/BCNT, Rh/MWCNT) catalysts were found to be the most active for liquid phase hydrogenation of octadecene amongst these samples. The initial olefin hydrogenation rate of the Pd/BCNT sample was slightly higher than the corresponding MWCNT-supported catalyst. Based on the hydrogenation reaction, the performance of these catalyst had been ranked as follows: Pd/BCNT ≈ Rh/MWCNT > Pd/MWCNT > Rh/BCNT >  > Ir/MWCNT > Ru/BCNT > Ir/BCNT > Ru/MWCNT. The structural properties of chemisorbed Pd on MWCNT and N- BCNT were also characterized by means of computational chemical methods in order to shed some light on the nature of metal binding properties of N-doped and undoped surfaces. The calculations shown preference towards the edges of the surfaces which is in good agreement with the experimental findings.

Granulated Carbon Nanotubes as the Catalyst Support for Pt for the Hydrogenation of Nitrobenzene

2010 ◽  
Vol 63 (1) ◽  
pp. 131 ◽  
Author(s):  
Shao Jin ◽  
Weizhong Qian ◽  
Yi Liu ◽  
Fei Wei ◽  
Dezeng Wang ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Mass Transfer ◽  
Catalytic Activity ◽  
Activated Carbon ◽  
Liquid Phase ◽  
Transfer Rate ◽  
High Selectivity ◽  
Mass Transfer Rate ◽  
Catalyst Support ◽  
Liquid Phase Hydrogenation

Granulated Pt/carbon nanotubes (CNTs) were found to have a much better catalytic activity in the liquid phase hydrogenation of nitrobenzene than Pt/activated carbon (AC). The granulated CNTs had much larger pores than the AC particles, which gave a faster mass transfer rate of H2 that helped produce aniline with high selectivity.

Catalytic Properties of Ni/CNTs and Ca-Promoted Ni/CNTs for Methanation Reaction of Carbon Dioxide

2014 ◽  
Vol 924 ◽  
pp. 217-226 ◽  
Author(s):  
Xiang Feng Hu ◽  
Wen Yang ◽  
Ning Wang ◽  
Shi Zhong Luo ◽  
Wei Chu
Keyword(s):  
Carbon Dioxide ◽  
Carbon Nanotubes ◽  
Catalytic Activity ◽  
Catalytic Properties ◽  
Supported Catalyst ◽  
Catalytic Performance ◽  
Impregnation Method ◽  
Methanation Reaction ◽  
Ni Species ◽  
Nickel Species

Nickel/carbon nanotubes (Ni/CNTs), Nickel/alumina (Ni/Al2O3), calcium-promoted Ni/CNTs and calcium-promoted Ni/Al2O3 were synthesized by impregnation method. Methanation of carbon dioxide was used as a probe to evaluate their catalytic performance. The features of these Ni-based catalysts were investigated via XRD, H2-TPR, H2-TPD and the N2 adsorptiondesorption isotherms. H2-TPR showed that nickel species on Ni/CNTs was reduced more easily with respect to that on Ni/Al2O3, and addition of Ca can increase the content of easily reducible Ni species for Ni/CNTs. XRD and H2-TPD indicated that addition of Ca promoted dispersion for CNTs-supported catalyst. These finding ultimately enhanced catalytic activity and stability for Ni/CNTs catalyst modified with Ca.

Nickel clusters grown on three-dimensional graphene oxide–multi-wall carbon nanotubes as an electrochemical sensing platform for luteolin at the picomolar level

RSC Advances ◽  
2015 ◽  
Vol 5 (79) ◽  
pp. 64739-64748 ◽  
Author(s):  
Taotao Yang ◽  
Yansha Gao ◽  
Jingkun Xu ◽  
Limin Lu ◽  
Yuanyuan Yao ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Graphene Oxide ◽  
Catalytic Activity ◽  
Electrochemical Sensor ◽  
Three Dimensional ◽  
Electrochemical Sensing ◽  
Multi Wall Carbon Nanotubes ◽  
Nickel Clusters ◽  
Sensing Platform

This study focuses on enhancing the catalytic activity of metallic Ni by using 1D MWCNTs, 2D GO and GR, and 3D GO–MWCNTs as supporting matrixs for the fabrication of electrochemical sensor for detecting the flavonoid luteolin.

Alumoxane Precursors to Designer Catalysts and Catalyst Supports: Catalytic Oxidation of Dichloromethane

1996 ◽  
Vol 454 ◽  
Author(s):  
Ron L. Cook ◽  
Cynthia Wong ◽  
C. Jeff Harlan ◽  
Aivaras Kareiva ◽  
Andrew R. Barron
Keyword(s):  
Catalytic Oxidation ◽  
Room Temperature ◽  
Catalyst Support ◽  
Catalytic Performance ◽  
Fine Tuning ◽  
Ceramic Oxides ◽  
Support Materials ◽  
Carboxylate Groups ◽  
Novel Catalyst ◽  
Traditional Approaches

ABSTRACTCarboxylato-alumoxanes are aluminum-oxygen macromolecules consisting of a boehmite-like core surrounded by a sheath of carboxylate groups. The alumoxanes may be processed like organic polymers yet when fired are readily transformed into ceramic oxides. The alumoxanes can be precisely doped at room temperature in aqueous solution with a range of metal cations to prepare novel catalyst and catalyst support materials. The ease of introduction of multiple cations into the alumina lattice via the alumoxane approach provides a method for fine-tuning catalyst support properties and the fabrication of new catalyst materials themselves. Manganese-doped alumina (Mn-Al2O3), formed via the doping of an alumoxane with Mn at room temperature, is presented as an example where the alumoxane route provides enhanced catalytic performance over traditional approaches for the low temperature catalytic oxidation of chlorinated hydrocarbons (CHCs). The Mn-Al2O3 formed from the Mn-doped alumoxane is compared with MnO2/Al2O3 prepared by the incipient wetness method, and commercial Pt/Al2O3 for the oxidation/destruction of dichloromethane (CH2Cl2).

scholarly journals Highly Efficient Liquid-Phase Hydrogenation of Naringin Using a Recyclable Pd/C Catalyst

Materials ◽  
2018 ◽  
Vol 12 (1) ◽  
pp. 46
Author(s):  
Jiamin Zhao ◽  
Ying Yuan ◽  
Xiuhong Meng ◽  
Linhai Duan ◽  
Rujin Zhou
Keyword(s):  
Catalytic Activity ◽  
Liquid Phase ◽  
Sodium Hydroxide ◽  
Catalyst Surface ◽  
Hydrogenation Reaction ◽  
Hydrogenation Process ◽  
Highly Efficient ◽  
Liquid Phase Hydrogenation ◽  
Palladium On Carbon

A highly efficient liquid-phase hydrogenation reaction using a recyclable palladium on carbon (Pd/C) catalyst has been used for the transformation of naringin to its corresponding dihydrochalcone. The effects of various solvents on the hydrogenation process were studied, with water being identified as the optimal solvent. The analysis also revealed that sodium hydroxide (NaOH) can accumulate on the surface of the Pd/C catalyst in alcoholic solvents, leading to its inactivation. The higher solubility of NaOH in water implies that it remains in solution and does not accumulate on the Pd/C catalyst surface, ensuring the catalytic activity and stability.

Synthesis and Characterization of Cu/ZnO Catalyst on Carbon Nanotubes and Al2O3 Supports

2018 ◽  
Vol 916 ◽  
pp. 139-143 ◽  
Author(s):  
Noor Asmawati Mohd Zabidi ◽  
Tuan Syahylah Tuan Sulong ◽  
Sardar Ali
Keyword(s):  
Carbon Nanotubes ◽  
Methyl Formate ◽  
Fixed Bed ◽  
Supported Catalyst ◽  
Hydrogenation Reaction ◽  
Fixed Bed Reactor ◽  
Incipient Wetness Impregnation ◽  
Impregnation Method ◽  
Attractive Option ◽  
Multi Walled Carbon Nanotubes

CO2 conversion into valuable chemicals is an attractive option to deal with the increasing CO2 concentration in the atmosphere. In this study, Cu/ZnO catalyst was synthesized on multi-walled carbon nanotubes (MWCNTs) and Al2O3 supports via incipient wetness impregnation method. The physicochemical properties of the catalysts were investigated using TEM, XRD, N2 adsorption-desorption analysis, H2-TPR and XPS. The performance of the synthesized catalysts in a CO2 hydrogenation reaction was evaluated in a fixed-bed reactor at 503 K, 22.5 bar and H2:CO2 ratio of 3:1. TEM images showed that Cu/ZnO nanoparticles were deposited inside the CNTs as well as on the exterior walls of the CNTs. The average CuO crystallite size on Al2O3 and CNTs supports was 15.7 and 11 nm, repectively. Results of H2-TPR studies showed that the reducibility of the catalyst was improved on the CNTs support. XPS analysis confirmed the presence of Cu2+ in the samples, however, the binding energy of Cu 2p3/2 peak on the Al2O3 support was shifted to higher value compared to that of CNTs support. Products obtained from the CO2 hydrogenation reaction in the presence of these catalyts were methanol, ethanol, methyl formate and methane. The CO2 conversion of around 23% was obtained using both types of catalysts, however, Cu/ZnO on CNTs resulted in higher yield of methyl formate compared to that of Al2O3-supported catalyst.

Incorporation of Multi Wall Carbon Nanotubes into Glass-Surfaces via Laser-Treatment

2003 ◽  
Vol 772 ◽  
Author(s):  
T. Seeger ◽  
G. de la Fuente ◽  
W.K. Maser ◽  
A.M. Benito ◽  
A. Righi ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Continuous Wave ◽  
Silica Surface ◽  
Multi Wall Carbon Nanotubes ◽  
Composite Formation ◽  
Multi Walled Carbon Nanotubes ◽  
Glass Surfaces ◽  
Walled Carbon Nanotubes ◽  
First Time ◽  
Scanning Electron

AbstractCarbon nanotubes (CNT) are interesting candidates for the reinforcement in robust composites and for conducting fillers in polymers due to their fascinating electronic and mechanical properties. For the first time, we report the incorporation of multi walled carbon nanotubes (MWNTs) into silica-glass surfaces by means of partial surface-melting caused by a continuous wave Nd:YAG laser. MWNTs were detected being well incorporated in the silica-surface. The composites are characterized using scanning electron microscopy (SEM) and Raman-spectroscopy. A model for the composite-formation is proposed based on heatabsorption by MWNTs and a partial melting of the silica-surface.

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