Effect of Heteroatom on Properties of SiO2-Supported Heteropolymolybdates

1998 ◽  
Vol 63 (11) ◽  
pp. 1927-1937 ◽  
Author(s):  
Alla Spojakina ◽  
Nina Kostova ◽  
Květa Jirátová
Keyword(s):  
Ir Spectroscopy ◽  
Lithium Salts ◽  
Temperature Programmed Reduction ◽  
Thiophene Conversion ◽  
Keggin Anions ◽  
Temperature Programmed

SiO2-supported trihydrogen phosphododecamolybdate acid H3PMo12O40 (denoted as H3PMo) and tetrahydrogen silicododecamolybdate acid H4SiMo12O40 (denoted as H4SiMo) and their lithium salts have been studied using IR spectroscopy, temperature programmed reduction and measurement of the thiophene conversion. Lacunar anions of H3PMo and, under some conditions, of H4SiMo are formed if lithium is present in the catalyst. Unlike the supported hetero polyacids, lithium combined with the analogues of defect Keggin anions formed during calcination enhances hydrodesulfurization of thiophene.

scholarly journals Composition of extraction products from alkylated high-sulphur coals

2003 ◽  
Vol 1 (4) ◽  
pp. 366-386 ◽  
Author(s):  
Mieczysław Kozłowski ◽  
Helena Wachowska ◽  
Jan Yperman
Keyword(s):  
Ir Spectroscopy ◽  
Elemental Analysis ◽  
Atmospheric Pressure ◽  
Liquid Ammonia ◽  
Temperature Programmed Reduction ◽  
Reductive Methylation ◽  
Aliphatic Compounds ◽  
Low Degree ◽  
Temperature Programmed ◽  
Degree Of Condensation

AbstractProducts of reductive and non-reductive methylation of two high-sulphur coals (Mequinenza and Illinois No. 6) have been extracted by dichloromethane. It has been established that the efficiency of the transformation of coal to the products soluble in CH2Cl2 is higher for coals subjected to non-reductive methylation by the Liotta method than for those after reduction in the potassium/liquid ammonia system. The extracts and the extraction residues were subjected to elemental analysis, IR spectroscopy, and AP-TPR (Atmospheric Pressure-Temperature Programmed Reduction) measurements. It has been shown that the main species undergoing extraction by CH2Cl2 are aliphatic compounds or aromatic structures of low degree of condensation. The effect of the extraction on the sulphur groups in coal has been discussed.

scholarly journals Novel Nickel- and Magnesium-Modified Cenospheres as Catalysts for Dry Reforming of Methane at Moderate Temperatures

Catalysts ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 1066 ◽  
Author(s):  
Bogdan Samojeden ◽  
Marta Kamienowska ◽  
Armando Izquierdo Colorado ◽  
Maria Elena Galvez ◽  
Ilona Kolebuk ◽  
...  
Keyword(s):  
Supported Catalysts ◽  
Temperature Programmed Desorption ◽  
Catalytic Performance ◽  
Dry Reforming ◽  
Dry Reforming Of Methane ◽  
Temperature Programmed Reduction ◽  
Fly Ashes ◽  
Coal Fly Ashes ◽  
Temperature Programmed ◽  
Mg Content

Cenospheres from coal fly ashes were used as support in the preparation of Ni–Mg catalysts for dry reforming of methane. These materials were characterized by means of XRD, H2-temperature-programmed reduction (H2-TPR), CO2-temperature-programmed desorption (CO2-TPD), and low-temperature nitrogen sorption techniques. The cenosphere-supported catalysts showed relatively high activity and good stability in the dry reforming of methane (DRM) at 700 °C. The catalytic performance of modified cenospheres was found to depend on both Ni and Mg content. The highest activity at 750 °C and 1 atm was observed for the catalyst containing 30 wt % Mg and 10, 20, and 30 wt % Ni, yielding to CO2 and CH4 conversions of around 95%.

Temperature-programmed reduction of CuO−NiO/Al2O3 catalysts

1982 ◽  
Vol 21 (3) ◽  
pp. 295-298 ◽  
Author(s):  
T. Paryjczak ◽  
J. Rynkowski ◽  
K. Krzyzanowski
Keyword(s):  
Temperature Programmed Reduction ◽  
Temperature Programmed

Preparation of Silica-Supported Nickel Molybdenum Phosphides by Temperature-Programmed Reduction Technique

2007 ◽  
Vol 124-126 ◽  
pp. 1765-1768 ◽  
Author(s):  
So Yeon Lee ◽  
Yong Kul Lee ◽  
S.Ted Oyama ◽  
Seok Hee Lee ◽  
Hee Chul Woo
Keyword(s):  
Single Phase ◽  
Reduction Rate ◽  
Reduction Reaction ◽  
Molar Ratio ◽  
Infrared Spectrometry ◽  
Molybdenum Oxides ◽  
Temperature Programmed Reduction ◽  
X Ray Diffraction ◽  
Ammonium Hydrogen ◽  
Temperature Programmed

Silica supported nickel molybdenum phosphides (NiMoP/SiO2) were successfully prepared by temperature-programmed reduction (TPR) reaction of phosphorous-impregnated nickel molybdenum oxides (NiMoO4) precursors with hydrogen at relatively low temperatures (530 – 590 oC) and characterized by Fourier transform-Infrared spectrometry (FT-IR), X-ray diffraction (XRD), Electron probe microanalysis (EPMA) and Temperature-programmed reduction reaction (TPR). The process of solid transformation and properties of materials prepared from ammonium hydrogen phosphate (AMP)-impregnated samples were compared with those of phosphide made from phosphoric acid (PAC)-impregnated samples. Results show that the formation of a single NiMoP phase on silica significantly depends on reduction rates, phosphorous sources and phosphorous loadings. A single phase of NiMoP on SiO2 was particularly promoted at a below 5 oC/min of reduction rate and the starting molar ratio of Ni/Mo/P=1/1/1. A single phase of crystalline NiMoP on silica was produced from AMP-impregnated samples, while other phases of MoP, Ni2P, or NiMoP2 were appeared from PAC-impregnated samples with loading. The new phase of NiMoP2 was occurred with increasing phosphorous loading (above Ni/Mo/P=1/1/2.5) as a result of facilitated contact on the surface between the Ni-Mo bimetallic component and the phosphorous reagent

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