X-Ray Diffraction Studies of the Action of Carbon Monoxide on Cobalt-Thoria-Kieselguhr Catalysts. I1

1947 ◽  
Vol 69 (10) ◽  
pp. 2497-2500 ◽  
Author(s):  
L. J. E. Hofer ◽  
W. C. Peebles
RSC Advances ◽  
2019 ◽  
Vol 9 (36) ◽  
pp. 20505-20512 ◽  
Author(s):  
Mixia Hu ◽  
YaLi Yan ◽  
Baohua Zhu ◽  
Fei Chang ◽  
Shiyong Yu ◽  
...  

Five Mn(i) photo-activated carbon monoxide-releasing molecules were synthesized by reactions of MnBr(CO)5 with L1–L4, and characterized via single crystal X-ray diffraction, 1H-NMR, 13C-NMR, IR, UV-vis and fluorescence spectroscopy.


1997 ◽  
Vol 62 (8) ◽  
pp. 1239-1253 ◽  
Author(s):  
Jonathan Bould ◽  
Paul Brint ◽  
John D. Kennedy ◽  
Mark Thornton-Pett ◽  
Lawrence Barton ◽  
...  

[6-(CO)-6-H-6,9-(PPh3)2-6P,5C-μ-(2-Ph2PC6H4)-arachno-6-IrB9H11] (1) results from the reaction of [6-H-6-(PPh3)-6P,5C-μ-(2-Ph2PC6H4)-nido-6-IrB9H12] (2) with carbon monoxide in refluxing benzene. It is characterised by NMR spectroscopy and by single-crystal X-ray diffraction analysis. Crystals were triclinic, space group P1, with a = 10.688(2), b = 13.114(3), c = 22.356(5) Å, α = 78.33(2), β = 89.482(10), γ = 70.884(12)°, and Z = 2. The compound is of the little-examined arachno ten-vertex metallaborane structural type. A second compound of this type, [6-(CO)-6-H-6,6-(PMe2Ph)2-9-(PPh3)-arachno-6-IrB9H11] (3), isolated from a reaction system involving [Ir(CO)Cl(PPh3)2], PMe2Ph and the [nido-B9H12]- anion, has also been characterised crystallographically. Crystals were triclinic, space group P1, with a = 10.389(1), b = 10.511(1), c = 19.699(3) Å, α = 75.03(1), β = 85.53(1), γ = 74.88(1)°, and Z = 2.


2020 ◽  
Vol 1010 ◽  
pp. 373-378
Author(s):  
Norliza Dzakaria ◽  
Maratun Najiha Abu Tahari ◽  
Salma Samidin ◽  
Tengku Shafazila Tengku Saharuddin ◽  
Fairous Salleh ◽  
...  

The reduction behaviour of cobalt doped with nickel oxide and undoped nickel oxide (NiO) by hydrogen (H2) in nitrogen (20%, v/v) and carbon monoxide (CO) in nitrogen (40%, v/v) atmospheres have been investigated by temperature programmed reduction (TPR). The phases formed of partially and completely reduced samples were characterized by X-ray diffraction spectroscopy (XRD). TPR results indicate that the reduction of Co doped and undoped nickel oxide in both reductants proceed in one step reduction (NiO → Ni) without intermediate. TPR results also suggested that by adding Co metal into NiO, the reduction to metallic Ni by both reductant gaseous give different intensity of the peak. The reduction process of Co and undoped NiO become faster when H2 was used as a reductant. Furthermore, in H2 atmosphere, Co-NiO give complete reduction to metallic Ni at 700 °C. Meanwhile, XRD analysis indicated that NiO without Co composed better crystallite phases of NiO with higher intensity.


2021 ◽  
Vol 21 (12) ◽  
pp. 6082-6087
Author(s):  
Chih-Wei Tang ◽  
Hsiang-Yu Shih ◽  
Ruei-Ci Wu ◽  
Chih-Chia Wang ◽  
Chen-Bin Wang

The increase of harmful carbon monoxide (CO) caused by incomplete combustion can affect human health even lead to suffocation. Therefore reducing the CO discharged by vehicles or factories is urgent to improve the air quality. The spinel cobalt (II, III) oxide (Co3O4) is an active catalyst for CO abatement. In this study, we tried to fabricate dispersing Co3O4 via the dispersion-precipitation method with acetic acid, formic acid, and oxalic acid as the chelating dispersants. Then, the asprepared samples were calcined at 300 ºC for 4 h to obtain active catalysts, and assigned as Co(A), Co(F) and Co(O) respectively, the amount of the dispersants used are labeled as I (0.12 mole), II (0.03 mole) and III (0.01 mole). For comparison, another CoAP sample was prepared via alkaliinduced precipitation and calcined at 300 ºC. All samples were characterized by X-ray diffraction (XRD), temperature-programmed reduction (TPR), scanning electron microscope (SEM), and nitrogen adsorption/desorption system, and the catalytic activity focused on the CO oxidation. The influence of chelating dispersant on the performance of abatement of CO was pursued in this study. Apparently, the results showed that the chelating dispersant can influence the catalytic activity of CO abatement. An optimized ratio of dispersant can improve the performance, while excess dispersant lessens the surface area and catalytic performance. The series of Co(O) samples can easily donate the active oxygen since the labile Co–O bonding and indicated the preferential performance than both Co(A) and Co(F) samples. The nanorod Co(O)-II showed preferential for CO oxidation, T50 and T90 approached 96 and 127 ºC, respectively. Also, the favorable durability of Co(O)-II sample maintains 95% conversion still for 50 h at 130 ºC and does not emerge deactivation.


2001 ◽  
Vol 86 (23) ◽  
pp. 5325-5328 ◽  
Author(s):  
K. F. Peters ◽  
C. J. Walker ◽  
P. Steadman ◽  
O. Robach ◽  
H. Isern ◽  
...  

2016 ◽  
Vol 840 ◽  
pp. 305-308
Author(s):  
Fairous Salleh ◽  
Tengku Shafazila Tengku Saharuddin ◽  
Alinda Samsuri ◽  
Rizafizah Othaman ◽  
Mohamed Wahab Mohamed Hisham ◽  
...  

The reduction behaviour of tungsten oxide has been studied by using temperature programmed reduction (TPR) and X-ray diffraction (XRD). The reduction behavior were examine by nonisothermal reduction up to 900 oC then continued with isothermal reduction at 900 oC for 45 min time under (40% v/v) carbon monoxide in nitrogen (CO in N2) atmosphere. The TPR signal clearly shows one peak attributed to formation of suboxide W18O49 (more) and WO2 (less) observed at 80 min. The reduction product was investigated by varying the holding reaction time. Based on the characterization of the reduction products by using XRD, it was found that, nonisothermal reduction of WO3 at temperature 900 oC partially converted to some W18O49 and WO2 phases. However, after increased the reaction holding time for 45 min, WO3 phases disappeared and converted to WO2 and W metal phases. It is obviously shows that by hold the reduction time could improve the reducibility of the sample oxide. Furthermore, it is suggested that reduction by using CO as reducing agent follows the consecutives steps WO3 → WO2.92 → W18O49 → WO2 → W.


2017 ◽  
Vol 888 ◽  
pp. 377-381
Author(s):  
Alinda Samsuri ◽  
Fairous Salleh ◽  
Tengku Shafazila Tengku Saharuddin ◽  
Rizafizah Othaman ◽  
Mohamed Wahab Mohamed Hisham ◽  
...  

The reduction behavior of silver doped molybdenum trioxide (Ag/MoO3) and undoped MoO3 by using carbon monoxide, CO were investigated by using temperature programmed reduction (TPR). The reduced phases were characterized by X-ray diffraction (XRD). In the carbon monoxide atmosphere, the XRD results indicated that the reduction of Ag/MoO3 and undoped MoO3 to MoO2 phase proceed in two steps (MoO3 → Mo4O11 → MoO2) with Mo4O11 present as an intermediate state. A complete reduction to metallic molybdenum for both samples cannot occurred since in an excess CO atmosphere, MoO2 is promoted to form carbides rather than reduce to metallic molybdenum. Nevertheless, addition of silver to modified MoO3 shows the better reducibility compared to MoO3 alone by lower the reducing temperature of MoO3. TPR results show that the reduction peak of Ag/MoO3 is slightly shifts to lower temperature as compared with the undoped MoO3. The interaction between silver and molybdenum ions leads to this slightly decrease of the reduction temperature of silver doped MoO3. It can be seen that doping with silver has a remarkable influence in the reduction process of the MoO3 catalyst.


2000 ◽  
Vol 65 (12) ◽  
pp. 1897-1910 ◽  
Author(s):  
Lenka Lukešová ◽  
Jiří Ludvík ◽  
Ivana Císařová ◽  
Petr Štěpnička

A series of complexes [M(CO)5(Hdpf-κP)], where M = Cr (1), Mo (2) and W (3), and Hdpf is 1'-(diphenylphosphanyl)ferrocenecarboxylic acid, was obtained by thermally-induced (2) or photochemically-assisted (1, 3) displacement of carbon monoxide with Hdpf from the corresponding hexacarbonyl complexes. The complexes were characterized by NMR, UV-VIS and IR spectroscopies and further studied by cyclic voltammetry. The solid-state structure of complex 1 has been determined by single-crystal X-ray diffraction.


Author(s):  
Henrik Land ◽  
Moritz Senger ◽  
Gustav Berggren ◽  
Sven T. Stripp

Even 20 years after the first crystal structures of [FeFe]-hydrogenase have been published, several aspects of biological hydrogen turnover are heatedly discussed. In this perspective, we give an overview on how the diversity of naturally occurring and artificially prepared, semi-synthetic [FeFe]-hydrogenases deepens our understanding of hydrogenase chemistry. In parallel, we cover new results from biophysical techniques that go beyond the scope of conventional electrochemistry, X-ray diffraction, EPR, and FTIR spectroscopy. Taking into account both proton transfer and electron transfer as well as the notorious sensitivity of [FeFe]-hydrogenases towards carbon monoxide, the discussion further touches upon the molecular proceedings of biological hydrogen turnover.


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