Ion-Exchanged Calcium from Calcium Carbonate and Low-Rank Coals:  High Catalytic Activity in Steam Gasification

1996 ◽  
Vol 10 (2) ◽  
pp. 431-435 ◽  
Author(s):  
Yasuo Ohtsuka ◽  
Kenji Asami
Keyword(s):  
Catalytic Activity ◽  
Calcium Carbonate ◽  
Steam Gasification ◽  
Low Rank ◽  
High Catalytic Activity ◽  
Low Rank Coals

Titanium Dioxide-Supported Sulfonated Low Rank Coal as Catalysts in the Oxidation of Styrene with Aqueous Hydrogen Peroxide

2014 ◽  
Vol 69 (5) ◽  
Author(s):  
Mukhamad Nurhadi ◽  
Jon Efendi ◽  
Lee Siew Ling ◽  
Teuku Meurah Indra Mahlia ◽  
Ho Chin Siong ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Titanium Dioxide ◽  
Catalytic Activity ◽  
Diffuse Reflectance Spectroscopy ◽  
Low Rank ◽  
Bet Surface Area ◽  
High Catalytic Activity ◽  
Low Rank Coal ◽  
X Ray Diffraction ◽  
Aqueous Hydrogen Peroxide

Titanium dioxide supported sulfonated low rank coal catalyst possesses high catalytic activity in liquid phase oxidation of styrene with aqueous hydrogen peroxide at room temperature. The catalysts were prepared by sulfonation with concentrated sulfuric acid and impregnation of titanium dioxide (500-2500 µmol). The effect of titanium dioxide impregnation and calcinations on the catalysts were studied by X-ray diffraction, UV-vis diffuse reflectance spectroscopy, Fourier transform infrared spectroscopy, BET surface area, field emission scanning electron microscopy and hydrophobicity measurement. The catalytic activity of the catalysts in the oxidation of styrene by aqueous H2O2 without calcination increased when the amount of titanium dioxide increased. Meanwhile, the catalytic activity of the catalyst calcined at 500oC for 2 h was lower than before calcination. It is suggested that the agglomeration of titanium dioxide and hydrophobicity play important role in the catalytic activity of titanium dioxide-supported sulfonated low rank coal in the oxidation of styrene with aqueous H2O2. 

Molecular modelling and experimental studies on steam gasification of low-rank coals catalysed by iron species

2008 ◽  
Vol 340 (1) ◽  
pp. 105-118 ◽  
Author(s):  
George Domazetis ◽  
Monthida Raoarun ◽  
Bruce D. James ◽  
John Liesegang
Keyword(s):  
Molecular Modelling ◽  
Experimental Studies ◽  
Steam Gasification ◽  
Low Rank ◽  
Iron Species ◽  
Low Rank Coals

scholarly journals Modification of Coal Char-loaded TiO2 by Sulfonation and Alkylsilylation to Enhance Catalytic Activity in Styrene Oxidation with Hydrogen Peroxide as Oxidant

2017 ◽  
Vol 12 (1) ◽  
pp. 55 ◽  
Author(s):  
Mukhamad Nurhadi
Keyword(s):  
Hydrogen Peroxide ◽  
Catalytic Activity ◽  
Active Sites ◽  
Catalyst Particle ◽  
Local Environment ◽  
Coal Char ◽  
Low Rank ◽  
High Catalytic Activity ◽  
Styrene Oxidation ◽  
Aqueous Hydrogen Peroxide

<p>The modified coal char from low-rank coal by sulfonation, titanium impregnation and followed by alkyl silylation possesses high catalytic activity in styrene oxidation. The surface of coal char was undergone several steps as such: modification using concentrated sulfuric acid in the sulfonation process, impregnation of 500 mmol titanium(IV) isopropoxide and followed by alkyl silylation of n-octadecyltriclorosilane (OTS). The catalysts were characterized by X-ray diffraction (XRD), IR spectroscopy, nitrogen adsorption, and hydrophobicity. The catalytic activity of the catalysts has been examined in the liquid phase styrene oxidation by using aqueous hydrogen peroxide as oxidant. The catalytic study showed the alkyl silylation could enhance the catalytic activity of Ti-SO<sub>3</sub>H/CC-600(2.0). High catalytic activity and reusability of the o-Ti-SO<sub>3</sub>H/CC-600(2.0) were related to the modification of local environment of titanium active sites and the enhancement the hydrophobicity of catalyst particle by alkyl silylation. Copyright © 2017 BCREC GROUP. All rights reserved</p><p><em>Received: 24<sup>th</sup> May 2016; Revised: 11<sup>st</sup> October 2016; Accepted: 18<sup>th</sup> October 2016</em></p><p><strong>How to Cite:</strong> Nurhadi, M. (2017). Modification of Coal Char-loaded TiO<sub>2</sub> by Sulfonation and Alkylsilylation to Enhance Catalytic Activity in Styrene Oxidation with Hydrogen Peroxide as Oxidant. <em>Bulletin of Chemical Reaction Engineering &amp; Catalysis</em>, 12 (1): 55-61 (doi:10.9767/bcrec.12.1.501.55-61)</p><p><strong>Permalink/DOI</strong>: http://dx.doi.org/10.9767/bcrec.12.1.501.55-61</p><p> </p>

scholarly journals Comparative Evaluation of Steam Gasification Reactivity of Indonesian Low Rank Coals

2016 ◽  
Vol 27 (6) ◽  
pp. 693-701 ◽  
Author(s):  
SOOHYUN KIM ◽  
PAUL VICTOR ◽  
JIHO YOO ◽  
SIHYUN LEE ◽  
YOUNGJOON RHIM ◽  
...  
Keyword(s):  
Comparative Evaluation ◽  
Steam Gasification ◽  
Low Rank ◽  
Gasification Reactivity ◽  
Low Rank Coals

Steam Gasification of Low-Rank Coals with Ion-Exchanged Sodium Catalysts Prepared Using Natural Soda Ash

2017 ◽  
Vol 31 (3) ◽  
pp. 2565-2571 ◽  
Author(s):  
Naoto Tsubouchi ◽  
Yuuki Mochizuki ◽  
Enkhsaruul Byambajav ◽  
Yuu Hanaoka ◽  
Takemitsu Kikuchi ◽  
...  
Keyword(s):  
Steam Gasification ◽  
Low Rank ◽  
Soda Ash ◽  
Low Rank Coals

Enhanced catalytic activity of low-Pt content nanocatalysts supported on hollow carbon spheres for the ORR in alkaline media

MRS Advances ◽  
2020 ◽  
Vol 5 (57-58) ◽  
pp. 2961-2972
Author(s):  
P.C. Meléndez-González ◽  
E. Garza-Duran ◽  
J.C. Martínez-Loyola ◽  
P. Quintana-Owen ◽  
I.L. Alonso-Lemus ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Anion Exchange ◽  
Average Particle Size ◽  
Synthesis Method ◽  
Alkaline Media ◽  
High Catalytic Activity ◽  
Average Particle ◽  
Carbon Spheres ◽  
Hollow Carbon ◽  
Hollow Carbon Spheres

In this work, low-Pt content nanocatalysts (≈ 5 wt. %) supported on Hollow Carbon Spheres (HCS) were synthesized by two routes: i) colloidal conventional polyol, and ii) surfactant-free Bromide Anion Exchange (BAE). The nanocatalysts were labelled as Pt/HCS-P and Pt/HCS-B for polyol and BAE, respectively. The physicochemical characterization of the nanocatalysts showed that by following both methods, a good control of chemical composition was achieved, obtaining in addition well dispersed nanoparticles of less than 3 nm TEM average particle size (d) on the HCS. Pt/HCS-B contained more Pt0 species than Pt/HCS-P, an effect of the synthesis method. In addition, the structure of the HCS remains more ordered after BAE synthesis, compared to polyol. Regarding the catalytic activity for the Oxygen Reduction Reaction (ORR) in 0.5 M KOH, Pt/HCS-P and Pt/HCS-B showed a similar performance in terms of current density (j) at 0.9 V vs. RHE than the benchmark commercial 20 wt. % Pt/C. However, Pt/HCS-P and Pt/HCS-B demonstrated a 6 and 5-fold increase in mass catalytic activity compared to Pt/C, respectively. A positive effect of the high specific surface area of the HCS and its interactions with metal nanoparticles and electrolyte, which promoted the mass transfer, increased the performance of Pt/HCS-P and Pt/HCS-B. The high catalytic activity showed by Pt/HCS-B and Pt/HCS-P for the ORR, even with a low-Pt content, make them promising cathode nanocatalysts for Anion Exchange Membrane Fuel Cells (AEMFC).

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