Temperature-programmed reduction and x-ray photoelectron spectroscopy of copper oxide on alumina following exposure to sulfur dioxide and oxygen

1991 ◽  
Vol 30 (9) ◽  
pp. 2105-2113 ◽  
Author(s):  
Benoit Kartheuser ◽  
Benjamin K. Hodnett ◽  
Alfredo Riva ◽  
Gabriele Centi ◽  
Haris Matralis ◽  
...  
Keyword(s):  
Sulfur Dioxide ◽  
Copper Oxide ◽  
Photoelectron Spectroscopy ◽  
Temperature Programmed Reduction ◽  
X Ray ◽  
Temperature Programmed

scholarly journals Deposition of Co onto Supported MoS2 by Water-Assisted Spreading: Increased Activity Promotion in Hydrodesulphurization of 1-Benzothiophene

Catalysts ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 987 ◽  
Author(s):  
Luděk Kaluža ◽  
Martin Koštejn ◽  
Daniela Gulková
Keyword(s):  
Photoelectron Spectroscopy ◽  
Temperature Programmed Reduction ◽  
Solubility In Water ◽  
X Ray ◽  
Activity Promotion ◽  
Hds Catalysts ◽  
Temperature Programmed ◽  
Increased Activity ◽  
Low Solubility ◽  
Scanning Electron

Hydrodesulphurization (HDS) catalysts were newly prepared by water-assisted spreading of CoCO3.Co(OH)2 of low solubility in water onto pre-sulphided Mo species supported on several Al2O3 of surface area SBET 77-262 m2g−1, ZrO2 of SBET 108 m2g−1, and TiO2 of SBET 140 m2g−1. The spreading was followed by scanning electron microscopy (SEM-EDX). X-ray photoelectron spectroscopy (XPS) and temperature programmed reduction (H2-TPR) characterized partial re-oxidation of sulphidic Mo catalysts before Co sorption. The prepared catalysts were characterized in sulphidic form by H2-TPR. Activity of catalysts was determined in the HDS reaction of 1-benzothiophene. The spreading of Co onto sulphidic catalysts led to systematic increase of HDS activity by 16–86% in comparison to the spreading of Co onto oxide samples.

scholarly journals Effect of Residual Na+ on the Combustion of Methane over Co3O4 Bulk Catalysts Prepared by Precipitation

Catalysts ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 427 ◽  
Author(s):  
Andoni Choya ◽  
Beatriz de Rivas ◽  
Jose Gutiérrez-Ortiz ◽  
Rubén López-Fonseca
Keyword(s):  
Photoelectron Spectroscopy ◽  
Near Infrared ◽  
Diffuse Reflectance Spectroscopy ◽  
Negative Impact ◽  
Methane Combustion ◽  
Molar Ratio ◽  
Temperature Programmed Reduction ◽  
X Ray ◽  
Two Samples ◽  
Temperature Programmed

The effect of the presence of residual sodium (0.4 %wt) over a Co3O4 bulk catalyst for methane combustion was studied. Two samples, with and without residual sodium, were synthesized by precipitation and thoroughly characterised by X-ray diffraction (XRD), N2 physisorption, Wavelength Dispersive X-ray Fluorescence (WDXRF), temperature-programmed reduction with hydrogen followed by temperature-programmed reduction with oxygen (H2-TPR/O2-TPO), temperature-programmed reaction with methane (CH4-TPRe), ultraviolet–visible–near-infrared diffuse reflectance spectroscopy (UV-vis-NIR DRS), Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). It was found that during calcination, a fraction of the sodium atoms initially deposited on the surface diffused and migrated into the spinel lattice, inducing a distortion that improved its textural and structural properties. However, surface sodium had an overall negative impact on the catalytic activity. It led to a reduction of surface Co3+ ions in favour of Co2+, thus ultimately decreasing the Co3+/Co2+ molar ratio (from 1.96 to 1.20) and decreasing the amount and mobility of active lattice oxygen species. As a result, the catalyst with residual sodium (T90 = 545 °C) was notably less active than its clean counterpart (T90 = 500 °C). All of this outlined the significance of a proper washing when synthesizing Co3O4 catalyst using a sodium salt as the precipitating agent.

A Temperature-Programmed-Reduction Study on La1−xSrxCrO3 and Surface-Ruthenium-Modified La1−xSrxCrO3

2006 ◽  
Vol 4 (1) ◽  
pp. 79-83 ◽  
Author(s):  
Aiyu Yan ◽  
Bin Liu ◽  
Baofeng Tu ◽  
Yonglai Dong ◽  
Mojie Cheng ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Perovskite Oxides ◽  
Reduction Peak ◽  
Temperature Programmed Reduction ◽  
X Ray Diffraction ◽  
X Ray ◽  
Composite Oxides ◽  
Temperature Programmed ◽  
Ru Species ◽  
A Site

A series of La1−xSrxCrO3(0⩽x⩽0.3) composite oxides were prepared by a modified citric method. These perovskite oxides were further modified with Ru through impregnation. X-ray diffraction, X-ray photoelectron spectroscopy (XPS) and temperature-programmed-reduction (TPR) techniques were adopted to investigate the properties of both the as-prepared perovskite oxides and the surface-Ru-modified La1−xSrxCrO3 samples. XPS results indicated the existence of Cr6+ ions in the fresh samples and transformed to Cr3+ after reduction. The hydrogen consumed by these perovskite oxides during TPR increased with the Sr doping, which was more than twice of the theoretical value according to Kröger-Vink notation. The reduction temperature of Cr ions of Ru∕La1−xSrxCrO3 significantly decreased with an increase of the Ru loading. A small reduction peak at ∼540°C, which was not shifted by increasing Ru loadings, was observed and could be ascribed to the reduction of trace chromate phases. On all TPR profiles of the three doped perovskites with unity of the A-site and B-site ratio, the reduction of Ru species could not be observed at low Ru loadings (0.05% and 0.1%). A reduction peak from RuO2 particles appeared at temperatures prior to the perovskite reduction on the TPR plots of modified La0.9Sr0.1CrO3 and La0.8Sr0.2CrO3 with high Ru loading (0.5% and 1%, respectively), but it did not occur with the Ru modified La0.7Sr0.3CrO3 in the investigated Ru loading range. The TPR results of the Ru modified La0.8Sr0.2Cr0.95O3 depicted that some Ru ions might be stabilized due to the incorporation into the oxide.

scholarly journals The effect of preparation method on the performance of PtSn/Al2O3 catalysts for acetic acid hydrogenation

2015 ◽  
Vol 17 (1) ◽  
pp. 11-17 ◽  
Author(s):  
Ke Zhang ◽  
Haitao Zhang ◽  
Hongfang Ma ◽  
Weiyong Ying ◽  
Dingye Fang
Keyword(s):  
Acetic Acid ◽  
Fourier Transform ◽  
Infrared Spectroscopy ◽  
Photoelectron Spectroscopy ◽  
Preparation Method ◽  
Chemical Properties ◽  
Temperature Programmed Reduction ◽  
Commercial Alumina ◽  
X Ray ◽  
Temperature Programmed

Abstract PtSn/Al2O3 catalysts with a given loading of 1 wt% Pt and 1 wt% Sn were prepared by co-impregnation or successive impregnation with aqueous solutions of Pt, Sn precursors and a commercial alumina. The catalysts were characterized by N2 adsorption, H2-TPR (H2 temperature-programmed reduction), H2-pulse chemisorption, XPS (X-ray photoelectron spectroscopy) and CO-FTIR (Fourier transform infrared spectroscopy), and tested in the hydrogenation of acetic acid. The results showed that the preparation method affected both the chemical properties and their performance in the hydrogenation of acetic acid. Sn enrichment on the catalysts surface was observed on the co-impregnated catalyst and catalyst in which the Pt precursor had been loaded first. It was found that the modification of Pt was a function of the sequence of Sn addition as revealed by CO-FTIR. Co-impregnated catalyst showed the highest activity and ethanol selectivity.

scholarly journals Effect of Ti on dibenzothiophene hydrodesulfurization performance over bulk Ni2P

2019 ◽  
Vol 44 (1) ◽  
pp. 45-54
Author(s):  
Chunbao Han ◽  
Hua Song ◽  
Nan Jiang ◽  
Yanguang Chen ◽  
Feng Li ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Molar Fraction ◽  
P System ◽  
Temperature Programmed Reduction ◽  
X Ray Diffraction ◽  
X Ray ◽  
Highly Dispersed ◽  
Temperature Programmed ◽  
Hydrodesulfurization Activity

A series of Ti-incorporated bulk Ni2P catalysts was prepared by means of temperature-programmed reduction, and the role of metallic Ti on the structure and catalytic activity of the Ni2P catalysts was studied. For this purpose, bulk Ni2P catalysts with metal Ti contents of 0.005 wt%, 0.01 wt%, and 0.02 wt% were synthesized. X-ray diffraction, CO uptake, Brunauer–Emmett–Teller measurements, and X-ray photoelectron spectroscopy were utilized to characterize the catalysts. Addition of titanium could increase the surface area and promote the formation of small, highly dispersed Ni2P particles. The Ti0.02-Ni2P system with a Ti molar fraction of 0.02 showed the highest hydrodesulfurization activity of 99.6%, which was an increase of 44% compared with that found for the bulk Ni2P.

scholarly journals Ni2P/Al2O3 hydrodesulfurization catalysts prepared from hypophosphite under a nitrogen atmosphere

2019 ◽  
Vol 45 ◽  
pp. 146867831987764
Author(s):  
Yunwu Yu ◽  
Lianjie Liang ◽  
Yunxue Liu ◽  
Changwei Xu ◽  
Qing Wang ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Reduction Method ◽  
Nitrogen Atmosphere ◽  
Deionized Water ◽  
Temperature Programmed Reduction ◽  
X Ray Diffraction ◽  
X Ray ◽  
Hydrodesulfurization Catalysts ◽  
Novel Method ◽  
Temperature Programmed

A novel method for preparing Ni2P/Al2O3(L) catalysts in an N2 atmosphere by decomposition of hypophosphites was proposed, and Ni2P/Al2O3(T) catalyst was synthesized by the temperature programmed reduction method in a H2 atmosphere for comparison. These prepared catalysts were washed with deionized water to remove impurities. The X-ray diffraction, N2-adsorption specific surface area measurements, CO uptake, and X-ray photoelectron spectroscopy were applied to characterize these catalysts. The activities of the Ni2P/Al2O3 catalysts prepared with the two different methods were tested in the dibenzothiophene hydrodesulfurization reaction.

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