scholarly journals High surface area MnO2 catalysts prepared by a metastable aqueous-aqueous interface method and their catalytic oxidation activity

2021 ◽  
Vol 947 (1) ◽  
pp. 012018
Author(s):  
Nguyen Thi Truc Phuong ◽  
Tran Thi Hong Ngoc ◽  
Le Nguyen Quang Tu ◽  
Nguyen Quang Long
Keyword(s):  
Surface Area ◽  
High Surface ◽  
High Surface Area ◽  
Catalytic Decomposition ◽  
Solution Concentration ◽  
Material Surface ◽  
Oxidation Activity ◽  
Typical Sample ◽  
Specific Material ◽  
Save Energy

Abstract In this work, the metastable aqueous-aqueous interfacial approach was used to prepare MnO2 with enhanced surface area, which helps to save energy, decrease cost and protect the environment. The material characteristic success was proven through using powder X-ray diffraction for the crystalline properties and N2 adsorption-desorption isotherm for high surface area. The relationship between the calcination temperature and the crystallinity as well the specific material surface area was also interested. The catalytic decomposition of hydrogen peroxide was investigated by the closed system measuring produced oxygen. After the H2O2 decomposition comparison between synthesized samples and commercial MnO2 in terms of both the efficiency and the speed, the M-200 sample was considered as a typical sample with outstanding performance to examine the reaction conditions (H2O2 solution concentration, catalyst amount and reaction temperature). The optimal reaction condition results are 0.9% H2O2 solution concentration, 0.2g/L catalyst, and room temperature. Besides, the leaching test and the catalytic regeneration were also conducted.

Oxidative Catalytic Decomposition of Toxic Gases Using Hydroxyapatite and Fluorhydroxyapatite

1994 ◽  
Vol 368 ◽  
Author(s):  
Timothy P. Palucka ◽  
Nicholas G. Eror ◽  
Thomas A. Mcnamara
Keyword(s):  
Surface Area ◽  
High Surface ◽  
High Surface Area ◽  
Catalytic Decomposition ◽  
Reaction Products ◽  
Fluorine Substitution ◽  
Dimethyl Methylphosphonate ◽  
Surface Areas ◽  
Percent Nitrogen ◽  
Protection Period

ABSTRACTAn oxidative catalytic route for the decomposition of nerve gases was investigated using hydroxyapatite (HA, chemical composition Ca10(PO4)6(OH)2) and its partially fluorinated analog fluorhydroxyapatite (FHA, Ca10(PO4)6Fx(OH)2−x). Samples were prepared with surface areas ranging from 34 to 238 m2/g to study surface area effects; 1.2 wt. % platinum was deposited on one substrate to investigate the effect of a transition metal on activity and selectivity. Reaction studies were performed using dimethyl methylphosphonate (DMMP), a nerve gas simulant, in a stream of 80 percent nitrogen and 20 percent oxygen at 573 K and atmospheric pressure. High surface area FHA samples showed an increase in the "protection period" (period of 100% conversion) with increasing fluorine substitution; such an increase was not seen for low surface area FHA samples. In the absence of platinum, the reaction products were methanol and dimethyl ether; with platinum, CO2 was also obtained.

High surface area La2Sn2O7 pyrochlore as a novel, active and stable support for Pd for CO oxidation

2015 ◽  
Vol 5 (4) ◽  
pp. 2270-2281 ◽  
Author(s):  
Jinshu Tian ◽  
Honggen Peng ◽  
Xianglan Xu ◽  
Wenming Liu ◽  
Youhe Ma ◽  
...  
Keyword(s):  
Co Oxidation ◽  
Hydrothermal Method ◽  
Surface Area ◽  
Active Oxygen Species ◽  
High Surface ◽  
High Surface Area ◽  
Active Oxygen ◽  
Oxygen Species ◽  
Oxidation Activity ◽  
Simple Hydrothermal Method

A mesoporous La2Sn2O7-HT pyrochlore with an unusually high surface area was successfully synthesized with a simple hydrothermal method at 200 °C. Due to its high surface area and the presence of more active oxygen species, Pd supported on this mesoporous La2Sn2O7-HT shows remarkable CO oxidation activity.

scholarly journals Characteristics of High Surface Area Molybdenum Nitride and Its Activity for the Catalytic Decomposition of Ammonia

Catalysts ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 192
Author(s):  
Seo-Hyeon Baek ◽  
Kyunghee Yun ◽  
Dong-Chang Kang ◽  
Hyejin An ◽  
Min Bum Park ◽  
...  
Keyword(s):  
Surface Area ◽  
Photoelectron Spectroscopy ◽  
High Surface ◽  
High Surface Area ◽  
Catalytic Decomposition ◽  
Molybdenum Nitride ◽  
X Ray ◽  
Temperature Programmed Oxidation ◽  
Oxidation Reduction ◽  
Temperature Programmed

High surface area (>170 m2 g−1) molybdenum nitride was prepared by the temperature-programmed nitridation of α-MoO3 with pure ammonia. The process was optimized by adjusting the experimental variables: the reaction temperature, heating rate, and molar flow rate of ammonia. The physicochemical properties of the as-formed molybdenum nitride were characterized by X-ray diffraction, N2 sorption, transmission electron microscopy, temperature-programmed oxidation/reduction, and X-ray photoelectron spectroscopy. Of the experimental variables, the nitridation temperature was found to be the most critical parameter determining the surface area of the molybdenum nitride. When the prepared molybdenum nitride was exposed to air, the specific surface area rapidly decreased because of the partial oxidation of molybdenum nitride to molybdenum oxynitride. However, the surface area recovered to 90% the initial value after H2 treatment. The catalyst with the highest degree of nitridation showed the best catalytic activity, superior to that of unmodified α-MoO3, for the decomposition of ammonia because of its high surface area.

A high surface area ordered mesoporous BiFeO3 semiconductor with efficient water oxidation activity

2015 ◽  
Vol 3 (4) ◽  
pp. 1587-1593 ◽  
Author(s):  
Ioannis Papadas ◽  
Joseph A. Christodoulides ◽  
George Kioseoglou ◽  
Gerasimos S. Armatas
Keyword(s):  
Surface Area ◽  
Water Oxidation ◽  
High Surface ◽  
High Surface Area ◽  
Internal Surface ◽  
Internal Surface Area ◽  
Oxidation Activity ◽  
Ordered Mesoporous ◽  
Reaction Performance

A mesoporous BiFeO3 semiconductor, possessing a large internal surface area, regular pore structure and highly crystalline walls, exhibits excellent oxygen evolution reaction performance with long-term cycling stability.

Tenacious Mass Transfer Limitations Drive Catalytic Selectivity during Electrochemical Carbon Dioxide Reduction

2019 ◽  
Author(s):  
Kailun Yang ◽  
Recep Kas ◽  
Wilson A. Smith
Keyword(s):  
Surface Area ◽  
High Surface ◽  
High Surface Area ◽  
Catalyst Layer ◽  
Active Surface ◽  
Active Surface Area ◽  
High Concentration ◽  
Copper Electrodes ◽  
Surface Enhanced ◽  
Local Current

<p>This study evaluated the performance of the commonly used strong buffer electrolytes, i.e. phosphate buffers, during CO<sub>2</sub> electroreduction in neutral pH conditions by using in-situ surface enhanced infrared absorption spectroscopy (SEIRAS). Unfortunately, the buffers break down a lot faster than anticipated which has serious implications on many studies in the literature such as selectivity and kinetic analysis of the electrocatalysts. Increasing electrolyte concentration, surprisingly, did not extend the potential window of the phosphate buffers due to dramatic increase in hydrogen evolution reaction. Even high concentration phosphate buffers (1 M) break down within the potentials (-1 V vs RHE) where hydrocarbons are formed on copper electrodes. We have extended the discussion to high surface area electrodes by evaluating electrodes composed of copper nanowires. We would like highlight that it is not possible to cope with high local current densities on these high surface area electrodes by using high buffer capacity solutions and the CO<sub>2</sub> electrocatalysts are needed to be evaluated by casting thin nanoparticle films onto inert substrates as commonly employed in fuel cell reactions and up to now scarcely employed in CO<sub>2</sub> electroreduction. In addition, we underscore that normalization of the electrocatalytic activity to the electrochemical active surface area is not the ultimate solution due to concentration gradient along the catalyst layer.This will “underestimate” the activity of high surface electrocatalyst and the degree of underestimation will depend on the thickness, porosity and morphology of the catalyst layer. </p> <p> </p>

scholarly journals Rugae-like FeP nanocrystal assembly on a carbon cloth: an exceptionally efficient and stable cathode for hydrogen evolution

Nanoscale ◽  
2015 ◽  
Vol 7 (25) ◽  
pp. 10974-10981 ◽  
Author(s):  
Xiulin Yang ◽  
Ang-Yu Lu ◽  
Yihan Zhu ◽  
Shixiong Min ◽  
Mohamed Nejib Hedhili ◽  
...  
Keyword(s):  
Gas Phase ◽  
Surface Area ◽  
Hydrogen Evolution ◽  
Hydrogen Generation ◽  
High Surface ◽  
High Surface Area ◽  
Catalytic Efficiency ◽  
Carbon Cloth ◽  
Nanocrystal Assembly

High surface area FeP nanosheets on a carbon cloth were prepared by gas phase phosphidation of electroplated FeOOH, which exhibit exceptionally high catalytic efficiency and stability for hydrogen generation.

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