scholarly journals Stable Performance of Supported PdOx Catalyst on Mesoporous Silica-Alumina of Water Tolerance for Methane Combustion under Wet Conditions

Catalysts ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 670
Author(s):  
Minseok Kim ◽  
Suhyun Lim ◽  
Chansong Kim ◽  
Chae-Ho Shin ◽  
Joon Hyun Baik ◽  
...  
Keyword(s):  
Mesoporous Silica ◽  
Particle Surface ◽  
Textural Properties ◽  
Methane Combustion ◽  
Lewis Acidity ◽  
Water Tolerance ◽  
Silica Alumina ◽  
Stable Performance ◽  
Temperature Programmed

In methane combustion, water tolerance of Pd-based catalysts is quite critical for stable performance, because water is produced in situ and a water-containing feed is used under real conditions. Herein, water-tolerant mesoporous silica-alumina (H-MSA) was prepared by solvent deficient precipitation (SDP) using triethoxy(octyl)silane (TEOOS) and aluminum isopropoxide (AIP). The H-MSA was more tolerant to water than γ-alumina, mesoporous alumina (MA), and mesoporous silica-alumina (MSA) synthesized by using tetraethyl orthosilicate (TEOS), because of the silica present on the external particle surface. Moreover, it exhibited better textural properties, leading to higher dispersion of PdOx. The PdOx catalyst supported on H-MSA was quite durable in repeated temperature-programmed cycles and isothermal tests in the presence of water vapor, compared to the reference PdOx catalysts. The measured stability was attributed to the water tolerance, weak Lewis acidity, and penta-coordinated Al species of the H-MSA support, which was preferentially imparted when TEOOS was added for substitution of 5 mol% AIP for the synthesis of H-MSA. Therefore, the SDP method employed herein is useful in endowing supported PdOx catalysts with the water tolerance necessary for stable methane combustion performance under wet conditions.

Synthesis of Highly Monodispersed Core/Shell Mesoporous Silica Spheres

2006 ◽  
Vol 45 ◽  
pp. 814-818
Author(s):  
Kazuhisa Yano ◽  
Tadashi Nakamura ◽  
Hiroshi Nozaki ◽  
Noritomo Suzuki ◽  
Yuusuke Akimoto
Keyword(s):  
Mesoporous Silica ◽  
Particle Surface ◽  
Core Shell ◽  
Silica Spheres ◽  
Laser Scattering ◽  
Monodispersed Particles ◽  
Core Shell Structure ◽  
Mesoporous Silica Spheres ◽  
Scattering Measurement

Particle size development of monodispersed mesoporous silica spheres (MMSS) was investigated by laser scattering measurement, TEM and XRD in situ. Smaller particles suddenly appeared after the commencement of the experiment, then growing homogeneously to larger particles. It is assumed that residual silica precursors in solution preferentially reacted with existing particle surface silanol, preventing generation of new particles. This leads to the formation of monodispersed particles. Based on the mechanism, monodispersed mesoporous silica spheres with core/shell structure have been newly synthesized.

In Situ Generation of Pd/PdO Nanoparticle Methane Combustion Catalyst: Correlation of Particle Surface Chemistry with Ignition

2009 ◽  
Vol 113 (48) ◽  
pp. 20632-20639 ◽  
Author(s):  
B. Van Devener ◽  
S. L. Anderson ◽  
T. Shimizu ◽  
H. Wang ◽  
J. Nabity ◽  
...  
Keyword(s):  
Surface Chemistry ◽  
Particle Surface ◽  
Methane Combustion ◽  
Combustion Catalyst ◽  
In Situ Generation

Dimerization of Hexadecene with Acid Mesoporous Silica‐Alumina Catalysts

2021 ◽  
Author(s):  
Narendra Kumar ◽  
Marina Lindblad ◽  
Jaana Makkonen ◽  
Väinö Sippola ◽  
Heidi Österholm ◽  
...  
Keyword(s):  
Mesoporous Silica ◽  
Silica Alumina ◽  
Alumina Catalysts

A facile and in situ approach to fluorescent mesoporous silica and its applications in sensing and bioimaging

2014 ◽  
Vol 2 (45) ◽  
pp. 9625-9630 ◽  
Author(s):  
Huangxin Zhou ◽  
Xun Lv ◽  
Ling Zhang ◽  
An Gong ◽  
Aiguo Wu ◽  
...  
Keyword(s):  
Mesoporous Silica

Pyrolysis of Hailar Lignite: Experiments with a Tubular Reactor and a Continuous Screw Kiln Reactor

2014 ◽  
Vol 672-674 ◽  
pp. 665-671
Author(s):  
Hao Jie Gao ◽  
Yue Zhao Zhu ◽  
Hai Jun Chen ◽  
Chuan Hua Liao ◽  
Yang Du ◽  
...  
Keyword(s):  
Moisture Content ◽  
Significant Influence ◽  
Tubular Reactor ◽  
Product Yield ◽  
Heating Process ◽  
Intermediate Products ◽  
Temperature Programmed ◽  
Gas Dilution ◽  
Pyrolysis Processes

Pyrolysis of Hailar lignite (moisture content ~ 34.81 wt%) was investigated at temperatures ranging from 700 °C to 900 °C in two different reactors: A tubular reactor (TR) and a continuous screw kiln reactor (CSKR). Under temperature programmed-heating conditions in the TR reactor, the auto-generated steam from the lignite moisture was vaporized and swept out of the reactor by the N2flow during the long heating process, leading to a weakened effect on the subsequent reactions. However, in the CSKR tests all the volatiles was generated continuously while avoid the carrier gas dilution , significant interactions between the in situ steam and the intermediate products occurred. Upon comparing the two pyrolysis processes, it was found the CSKR process exhibits higher H2yield of 23.23 mol/kg, H2proportion of 49.82 vol % than those (16.97 mol/kg, 41.51 vol %) from the TR process. The results demonstrated that inherent moisture in Hailar lignite had a significant influence on the product yield, depending on the pyrolysis conditions. It was also shown that increase in temperature led to rising dry gas yield and H2yield.

Hydrogen Adsorption Capacity Investigation of Ni-Co-Al Mixed Oxides

2014 ◽  
Vol 917 ◽  
pp. 360-364 ◽  
Author(s):  
M. Abdus Salam ◽  
Suriati Sufian
Keyword(s):  
Hydrogen Adsorption ◽  
Mixed Oxides ◽  
Textural Properties ◽  
Metal Dispersion ◽  
Temperature Programmed Reduction ◽  
Oxide Formation ◽  
Nickel Cobalt ◽  
Icp Ms ◽  
Temperature Programmed ◽  
Adsorption Desorption

Micro-mesoporous mixed oxides containing nickel, cobalt and aluminum have been synthesized using conventional coprecipitation method. FESEM and HRTEM analyses demonstrated the flower and hexagonal plate-like nanostructured of mixed oxides. Different mixed oxide formation, homogenous metal dispersion, textural properties were investigated using XRD, ICP-MS and BET (N2 adsorption-desorption) techniques. nanostructured mixed oxides exhibited 2.6 wt% hydrogen adsorption that were studied using temperature programmed reduction-adsorption-desorption (H2-TPR/TPD) and thermogravimetric and differential thermal analysis (TGA-DTA) techniques. Investigation corresponds that morphologies, textural properties and surface energy of mixed oxides are important in hydrogen adsorption.

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