Synthesis, Structural and Electrochemical Characterization of Honeycomb Supported Pt-Pd-Rh Composite Catalyst for the Decomposition of Gaseous Ammonia to Nitrogen

2011 ◽  
Vol 214 ◽  
pp. 21-25 ◽  
Author(s):  
Chang Mao Hung
Keyword(s):  
Fixed Bed ◽  
Ceramic Materials ◽  
Composite Catalyst ◽  
Gaseous Ammonia ◽  
Incipient Wetness Impregnation ◽  
Selective Catalytic Oxidation ◽  
High Initial Concentration ◽  
Nh3 Oxidation ◽  
Cellular Ceramic

The behavior of the ammonia (NH3) oxidation was by selective catalytic oxidation (SCO) over a honeycomb supported Pt-Pd-Rh composite catalyst in a tubular fixed-bed flow quartz reactor (TFBR) at 673 K. A honeycomb Pt-Pd-Rh composite catalyst was prepared by incipient wetness impregnation with aqueous solutions of H2PtCl6, Pd(NO3)3 and Rh(NO3)3 that were coated on cordierite cellular ceramic materials. The catalysts surface properties were characterized using OM. The experimental results show that contaminants crystal aggregation phases and washcoat loss from high initial concentration of NH3 may be responsible for the deactivation of the catalysts. In addition, the catalytic redox behavior was determined by cyclic voltammetric (CV), which showed that the catalytic behavior is related to the metal oxide properties of the catalyst.

Preparation, Properties and Cytotoxicity Assessment of Nanosized Pt-Rh Composite Catalyst for the Decomposition of Gaseous Ammonia

2010 ◽  
Vol 160-162 ◽  
pp. 1285-1290
Author(s):  
Chang Mao Hung
Keyword(s):  
Catalytic Oxidation ◽  
Active Sites ◽  
Human Lung ◽  
Fixed Bed ◽  
Composite Catalyst ◽  
Gaseous Ammonia ◽  
Human Lung Cells ◽  
Selective Catalytic Oxidation ◽  
Catalytically Active

The behavior of the ammonia (NH3) oxidation was by selective catalytic oxidation (SCO) over a nanosized Pt-Rh composite catalyst in a tubular fixed-bed flow quartz reactor (TFBR) at temperatures between 423 and 673 K. The catalysts surface properties were characterized using UV-Vis and TEM. The experimental results show high activities for NH3 removal was achieved during catalytic oxidation over the Pt-Rh catalyst at 673 K with an oxygen content of 4%. N2 was the main product in the NH3-SCO process over the nanosized Pt-Rh composite catalyst. These results also verify that the Pt-Rh metals on catalyst surfaces, resulting in the formation of the remarkable catalytically active sites at the metal-support interface in the reduction of NH3 in this process. In addition, the nanosized Pt-Rh composite-induced cytotoxicity testing was mainly applied to the human lung MRC-5 cell line and the percentage of cell survival was determined by MTS analysis in vitro. For nanosized Pt-Rh composite, only minor cytotoxicity was observed when human lung cells were exposed.

The Influence of the Cobalt-Containing Component of the Composite Catalyst on the One-Stage Process for Synthesis of Liquid Hydrocarbons from CO and H2

2019 ◽  
Vol 19 (3) ◽  
pp. 178-186
Author(s):  
R. E. Yakovenko ◽  
I. N. Zubkov ◽  
G. B. Narochnyi ◽  
S. V. Nekroenko ◽  
A. P. Savost’yanov
Keyword(s):  
Catalyst Deactivation ◽  
Molecular Mass Distribution ◽  
Fixed Bed ◽  
Gasoline Fraction ◽  
Fixed Bed Reactor ◽  
Composite Catalyst ◽  
Liquid Hydrocarbons ◽  
Stage Process ◽  
The One

The influence of the cobalt-containing component (Co-Al2O3/SiO2, Co-Re/Al2O3 and Co-Re/TiO2) of a composite catalyst was studied in the Fischer – Tropsch combined process for synthesis and hydrotransformation of hydrocarbons. A flow fixed-bed reactor was used for characterization of the catalytic properties at 2 MPa, flow rate 1000 h–1, 240–280 °C for 40–90 hours of continuous operation. The highest productivity and selectivity to C5+ hydrocarbons equal to 106 kg/(m3 cat·ч) and 67.1 %, respectively, was characteristic of the composite catalyst Co-Al2O3/SiO2(35%)/ZSM-5(30%)/Al2O3(30%) at 240 °C. The comparable activities were observed with the catalysts Co-Re/Al2O3 and Co-Al2O3/SiO2 but the former provided the formation of unsaturated hydrocarbons in a lower proportion in the products. The use of the Co-Re/TiO2 catalyst at elevated temperature (up to 280 °C) allowed the molecular mass distribution of the products to be shifted towards the formation of the gasoline fraction. The rate of the catalyst deactivation was established to increase in the series Co-Al2O3/SiO2 > Co-Re/Al2O3 > Co-Re/TiO2.

Preparation, Electrochemical Properties and Cytotoxicity Assessment of Nanosized CuO/La2O3/CeO2 Composite for the Decomposition of Gaseous Ammonia

2011 ◽  
Vol 695 ◽  
pp. 53-56
Author(s):  
Chang Mao Hung
Keyword(s):  
Rare Earth ◽  
Composite Materials ◽  
Fixed Bed ◽  
Fetal Lung ◽  
Copper Nitrate ◽  
Fixed Bed Reactor ◽  
Gaseous Ammonia ◽  
Tissue Cell ◽  
Selective Catalytic Oxidation ◽  
Cytotoxicity Assessment

This work considers the CuO/La2O3/CeO2nano-rare earth composite materials were synthesized by coprecipitation method with aqueous solutions of copper nitrate, lanthanum nitrate and cerium nitrate. The performance of the selective catalytic oxidation of ammonia to N2(NH3-SCO) over a CuO/La2O3/CeO2nano-rare earth composite materials in a tubular fixed-bed reactor (TFBR) at temperatures from 423 to 673 K in the presence of oxygen was reported. The catalytic redox behaviors were determined by cyclic voltammetry (CV). Further, cell cytotoxicity and the percentage cell survival were determined by using MTS assay on human fetal lung tissue cell (MRC-5). The experimental results show that the CuO/La2O3/CeO2nanocomposite particles only minor cause cytotoxicity effect in cultured human cells.

Interface structures in polycrystalline ceramic materials

1986 ◽  
Vol 44 ◽  
pp. 468-471
Author(s):  
K. J. Morrissey
Keyword(s):  
Electron Microscopy ◽  
Analytical Electron Microscopy ◽  
Physical And Mechanical Properties ◽  
High Resolution Electron Microscopy ◽  
Ceramic Materials ◽  
Polycrystalline Materials ◽  
Transmission Electron ◽  
Resolution Electron ◽  
Interface Structures

Grain boundaries and interfaces play an important role in determining both physical and mechanical properties of polycrystalline materials. To understand how the structure of interfaces can be controlled to optimize properties, it is necessary to understand and be able to predict their crystal chemistry. Transmission electron microscopy (TEM), analytical electron microscopy (AEM,), and high resolution electron microscopy (HREM) are essential tools for the characterization of the different types of interfaces which exist in ceramic systems. The purpose of this paper is to illustrate some specific areas in which understanding interface structure is important. Interfaces in sintered bodies, materials produced through phase transformation and electronic packaging are discussed.

scholarly journals Tungsten Oxide-Modified SSZ-13 Zeolite as an Efficient Catalyst for Ethylene-To-Propylene Reaction

Catalysts ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 553
Author(s):  
Mansurbek Urol ugli Abdullaev ◽  
Sungjune Lee ◽  
Tae-Wan Kim ◽  
Chul-Ung Kim
Keyword(s):  
Tungsten Oxide ◽  
Fixed Bed ◽  
Acid Sites ◽  
Fixed Bed Reactor ◽  
Incipient Wetness Impregnation ◽  
Impregnation Method ◽  
Efficient Catalyst ◽  
X Ray ◽  
Propylene Selectivity ◽  
Temperature Programmed

Among the zeolitic catalysts for the ethylene-to-propylene (ETP) reaction, the SSZ-13 zeolite shows the highest catalytic activity based on both its suitable pore architecture and tunable acidity. In this study, in order to improve the propylene selectivity further, the surface of the SSZ-13 zeolite was modified with various amounts of tungsten oxide ranging from 1 wt% to 15 wt% via a simple incipient wetness impregnation method. The prepared catalysts were characterized with several analysis techniques, specifically, powder X-ray diffraction (PXRD), Raman spectroscopy, temperature-programmed reduction of hydrogen (H2-TPR), temperature-programmed desorption of ammonia (NH3-TPD), inductively coupled plasma-atomic emission spectroscopy (ICP-AES), and N2 sorption, and their catalytic activities were investigated in a fixed-bed reactor system. The tungsten oxide-modified SSZ-13 catalysts demonstrated significantly improved propylene selectivity and yield compared to the parent H-SSZ-13 catalyst. For the tungsten oxide loading, 10 wt% loading showed the highest propylene yield of 64.9 wt%, which was 6.5 wt% higher than the pristine H-SSZ-13 catalyst. This can be related to not only the milder and decreased strong acid sites but also the diffusion restriction of bulky byproducts, as supported by scanning transmission electron microscopy-energy dispersive X-ray spectroscopy (STEM-EDS) observation.

scholarly journals Fabrication and characterization of the ternary composite catalyst system of ZnGA/RET/DMC for the terpolymerization of CO2, propylene oxide and trimellitic anhydride

RSC Advances ◽  
2021 ◽  
Vol 11 (15) ◽  
pp. 8782-8792
Author(s):  
Ningzhang Liu ◽  
Chuanhai Gu ◽  
Qinghe Wang ◽  
Linhua Zhu ◽  
Huiqiong Yan ◽  
...  
Keyword(s):  
Propylene Oxide ◽  
Ternary Complex ◽  
Catalyst System ◽  
Composite Catalyst ◽  
Trimellitic Anhydride ◽  
Ternary Composite ◽  
Metal Cyanide ◽  
Fabrication And Characterization ◽  
Poly Propylene

For poly(propylene carbonate trimellitic anhydride) with good yield, thermal stability and high molecular weight, a catalyst of zinc glutarate/rare earth ternary complex/double metal cyanide was used for terpolymerization of CO2, propylene oxide and trimellitic anhydride.

Investigation and Characterization of Clay Mixture Feedstock for Extrusion-Based Additive Manufacturing

2020 ◽  
Author(s):  
Tawaddod Alkindi ◽  
Mozah Alyammahi ◽  
Rahmat Agung Susantyoko
Keyword(s):  
Cost Efficiency ◽  
Ceramic Materials ◽  
3D Printer ◽  
Mixing Processes ◽  
Ceramic Components ◽  
Computer Controlled ◽  
Continuous Material ◽  
Printing Speed

Abstract The extrusion-based AM technique has been recently employed for rapid ceramic components fabrication due to scalability and cost-efficiency. This paper investigated aspects of the extrusion technique to print ceramic materials. Specifically, we assessed and developed a process recipe of the formulations (the composition of water and ethanol-based clay mixtures) and mixing processes. Different clay paste formulations were prepared by varying clay, water, ethanol ratios. The viscosity of clay paste was measured using a DV3T Viscometer. Afterward, the produced clay paste was used as a feedstock for WASP Delta 60100 3D printer for computer-controlled extrusion deposition. We evaluated the quality of the clay paste based on (i) pumpability, (ii) printability, and (iii) buildability. Pressure and flow rate were monitored to assess the pumpability. The nozzle was monitored for continuous material extrusion to assess printability. The maximum layer-without-collapse height was monitored to assess the buildability. This study correlated the mixture composition and process parameters, to the viscosity of the mixture, at the same printing speed. We found that 85 wt% clay, 5 wt% water, 10 wt% ethanol paste formulation, with the viscosity of 828000 cP, 202400 cP, 40400 cP at 1, 5, and 50 rpm, respectively, demonstrates good pumpability, as well as best printability and buildability.

Synthesis and characterization of cobalt-doped molybdenum carbides produced in a fixed bed reactor

2018 ◽  
Vol 44 (16) ◽  
pp. 20551-20555 ◽  
Author(s):  
S.L.A. Dantas ◽  
A.L. Lopes-Moriyama ◽  
M.S. Sena ◽  
C.P. Souza
Keyword(s):  
Fixed Bed ◽  
Fixed Bed Reactor ◽  
Synthesis And Characterization ◽  
Molybdenum Carbides
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