Surface hydroxyls mediated CO2 methanation at ambient pressure over attapulgite-loaded Ni-TiO2 composite catalysts with high activity and reuse ability

2021 ◽  
Vol 47 ◽  
pp. 101489
Author(s):  
Zairong Yan ◽  
Qinghe Liu ◽  
Lixing Liang ◽  
Jing Ouyang
Keyword(s):  
High Activity ◽  
Ambient Pressure ◽  
Co2 Methanation ◽  
Composite Catalysts ◽  
Surface Hydroxyls

Sponge Ni catalyst with high activity in CO2 methanation

2017 ◽  
Vol 42 (51) ◽  
pp. 30126-30134 ◽  
Author(s):  
Shohei Tada ◽  
Shun Ikeda ◽  
Naohiro Shimoda ◽  
Tetsuo Honma ◽  
Makoto Takahashi ◽  
...  
Keyword(s):  
High Activity ◽  
Ni Catalyst ◽  
Co2 Methanation

scholarly journals Toward Green Production of Chewing Gum and Diet: Complete Hydrogenation of Xylose to Xylitol over Ruthenium Composite Catalysts under Mild Conditions

Research ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Cai-Juan Liu ◽  
Ning-Ning Zhu ◽  
Jian-Gong Ma ◽  
Peng Cheng
Keyword(s):  
Ambient Pressure ◽  
Environmentally Benign ◽  
Composite Catalyst ◽  
Chewing Gum ◽  
Energy Costs ◽  
Reaction Conditions ◽  
Composite Catalysts ◽  
Successful Attempt ◽  
Green Production ◽  
First Time

Xylitol is one of the most famous chemicals known to people as the essential ingredient of chewing gum and as the sugar alternative for diabetics. Catalytic hydrogenation of biomass-derived xylose with H2 to produce high-value xylitol has been carried out under harsh reaction conditions. Herein, we exhibit the combination of Ru NPs with an environmentally benign MOF (ZIF-67) to afford a heterogeneous composite catalyst. Complete conversion of xylose with 100% selectivity to xylitol was achieved at 50°C and 1 atm H2. This is the first successful attempt to produce xylitol with ambient pressure H2 as well as the first time to achieve a 100% selectivity of xylitol for applicable catalysts. We also proved the universality of the Ru@ZIF-67 towards other hydrogenation processes. Under 1 atm H2, we achieved 100% conversion and >99% selectivity of 1-phenylethanol at 50°C for the hydrogenation of acetophenone. This is also the first report of hydrogenating acetophenone to 1-phenylethanol under 1 atm H2, which confirms that our result not only contributes to enhance the industrial yields of xylitol and reduces both the economical and energy costs but also provides new perspectives on the other hydrogenation process with H2.

Synthesis of zinc/ferrocyanide nano-composite catalysts having a high activity for transesterification reaction

2020 ◽  
Vol 148 ◽  
pp. 946-952 ◽  
Author(s):  
Praveen Kumar ◽  
Lev Matoh ◽  
Vimal Chandra Srivastava ◽  
Urška Lavrenčič Štangar
Keyword(s):  
High Activity ◽  
Transesterification Reaction ◽  
Nano Composite ◽  
Composite Catalysts

scholarly journals Ni nanocatalysts supported on mesoporous Al2O3–CeO2 for CO2 methanation at low temperature

RSC Advances ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 2067-2072 ◽  
Author(s):  
Yushan Wu ◽  
Jianghui Lin ◽  
Guangyuan Ma ◽  
Yanfei Xu ◽  
Jianli Zhang ◽  
...  
Keyword(s):  
Low Temperature ◽  
Oxygen Vacancies ◽  
Metallic Nickel ◽  
Co2 Methanation ◽  
Composite Catalysts

The addition of CeO2 to form Ni composite catalysts increased the oxygen vacancies and active metallic nickel sites thus improving the low temperature CO2 methanation performance.

scholarly journals Reaction Pathway for Coke-Free Methane Steam Reforming on a Ni/CeO2 Catalyst: Active Sites and Role of Metal-Support Interactions

2021 ◽  
Author(s):  
Agustin Salcedo ◽  
Pablo Lustemberg ◽  
Ning Rui ◽  
Robert M. Palomino ◽  
Zongyuan Liu ◽  
...  
Keyword(s):  
High Activity ◽  
Steam Reforming ◽  
Active Sites ◽  
Density Functional ◽  
Ambient Pressure ◽  
Carbon Accumulation ◽  
Methane Steam Reforming ◽  
Severe Problem ◽  
Methane Steam ◽  
Water Activation

<p>Methane steam reforming (MSR) plays a key role in the production of syngas and hydrogen from natural gas. The increasing interest in the use of hydrogen for fuel cell applications demands the development of catalysts with high activity at reduced operating temperatures. Ni-based catalysts are promising systems because of their high activity and low cost, but coke formation generally poses a severe problem. Studies of ambient-pressure X-ray photoelectron spectroscopy (AP-XPS) indicate that CH<sub>4</sub>/H<sub>2</sub>O gas mixtures react with Ni/CeO<sub>2</sub>(111) surfaces to form OH, CH<i><sub>x</sub></i> and CH<i><sub>x</sub></i>O at 300 K. All these species are easy to form and desorb at temperatures below 700 K when the rate of the MSR process accelerates. Density functional theory (DFT) modeling of the reaction over ceria-supported small Ni nanoparticles predicts relatively low activation barriers between 0.3–0.7 eV for the complete dehydrogenation of methane to carbon and the barrierless activation of water at interfacial Ni sites. Hydroxyls resulting from water activation allow CO formation via a COH intermediate with a barrier of about 0.9 eV, which is much lower than that through a pathway involving lattice oxygen from ceria. Neither methane nor water activation are rate-determining steps, and the OH-assisted CO formation through the COH intermediate constitutes a low-barrier pathway that prevents carbon accumulation. The interaction between Ni and the ceria support and the low metal loading are crucial for the reaction to proceed in a coke-free and efficient way. These results could pave the way for further advances in the design of stable and highly active Ni-based catalysts for hydrogen production.</p>

scholarly journals Reaction Pathway for Coke-Free Methane Steam Reforming on a Ni/CeO2 Catalyst: Active Sites and Role of Metal-Support Interactions

2021 ◽  
Author(s):  
Agustin Salcedo ◽  
Pablo Lustemberg ◽  
Ning Rui ◽  
Robert M. Palomino ◽  
Zongyuan Liu ◽  
...  
Keyword(s):  
High Activity ◽  
Steam Reforming ◽  
Active Sites ◽  
Density Functional ◽  
Ambient Pressure ◽  
Carbon Accumulation ◽  
Methane Steam Reforming ◽  
Severe Problem ◽  
Methane Steam ◽  
Water Activation

<p>Methane steam reforming (MSR) plays a key role in the production of syngas and hydrogen from natural gas. The increasing interest in the use of hydrogen for fuel cell applications demands the development of catalysts with high activity at reduced operating temperatures. Ni-based catalysts are promising systems because of their high activity and low cost, but coke formation generally poses a severe problem. Studies of ambient-pressure X-ray photoelectron spectroscopy (AP-XPS) indicate that CH<sub>4</sub>/H<sub>2</sub>O gas mixtures react with Ni/CeO<sub>2</sub>(111) surfaces to form OH, CH<i><sub>x</sub></i> and CH<i><sub>x</sub></i>O at 300 K. All these species are easy to form and desorb at temperatures below 700 K when the rate of the MSR process accelerates. Density functional theory (DFT) modeling of the reaction over ceria-supported small Ni nanoparticles predicts relatively low activation barriers between 0.3–0.7 eV for the complete dehydrogenation of methane to carbon and the barrierless activation of water at interfacial Ni sites. Hydroxyls resulting from water activation allow CO formation via a COH intermediate with a barrier of about 0.9 eV, which is much lower than that through a pathway involving lattice oxygen from ceria. Neither methane nor water activation are rate-determining steps, and the OH-assisted CO formation through the COH intermediate constitutes a low-barrier pathway that prevents carbon accumulation. The interaction between Ni and the ceria support and the low metal loading are crucial for the reaction to proceed in a coke-free and efficient way. These results could pave the way for further advances in the design of stable and highly active Ni-based catalysts for hydrogen production.</p>

Environmental microscopy of capillary stress-induced strain behavior in ambient-pressure aerogels

1996 ◽  
Vol 54 ◽  
pp. 850-851
Author(s):  
Sudeep M. Rao ◽  
Joshua Samuel ◽  
Sai S. Prakash ◽  
C. Jeffrey Brinker
Keyword(s):  
Silica Aerogel ◽  
Ambient Pressure ◽  
Drying Shrinkage ◽  
Pore Filling ◽  
Silica Network ◽  
Strain Behavior ◽  
Partially Saturated ◽  
Capillary Stress ◽  
Wetting Liquid ◽  
Aerogel Films

Ambient pressure silica aerogel thin films have recently been prepared by exploiting reversible drying shrinkage caused by derivatization of the internal gel surface. Aerogels have porosities of upto 99.9% and due to the small size of the pores (few nanometers), large capillary stresses are produced in gels that are partially saturated with a wetting liquid. As a result of these capillary stresses, the flexible silica network undergoes strain which has been observed using environmental microscopy. This technique allows variation of the equilibrium vapor pressure and temperature, and a simultaneous monitoring of the deformation of the unconstrained film thickness. We have observed >600% deformation during the pore-filling and pore-emptying cycles. In this presentation, we discuss the unique stress-strain behavior of these films.Ref.: Sai S. Prakash, C. Jeffrey Brinker, Alan J. Hurd & Sudeep M. Rao, "Silica aerogel films prepared at ambient pressure by using surface derivatization to induce reversible drying shrinkage", Nature. Vol. 374, 30 March, 1995, 439-443.

ON MAGNETIC PROPERTIES 0F (TMTSF)2PF6AT AMBIENT PRESSURE

1983 ◽  
Vol 44 (C3) ◽  
pp. C3-1001-C3-1005
Author(s):  
S. Iwabuchi ◽  
H. Fukuyama
Keyword(s):  
Magnetic Properties ◽  
Ambient Pressure

High-activity samarium-153-EDTMP therapy followed by autologous peripheral blood stem cell support in unresectable osteosarcoma

2001 ◽  
Vol 40 (06) ◽  
pp. 215-220 ◽  
Author(s):  
S. Bielack ◽  
S. Flege ◽  
J. Eckardt ◽  
J. Sciuk ◽  
H. Jürgens ◽  
...  
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
High Activity ◽  
Peripheral Blood ◽  
Peripheral Blood Stem Cell ◽  
Blood Stem Cell ◽  
High Dose ◽  
External Radiotherapy ◽  
Primary Tumor Site ◽  
Hematopoietic Stem

Summary Purpose: Despite highly efficacious chemotherapy, patients with osteosarcomas still have a poor prognosis if adequate surgical control cannot be obtained. These patients may benefit from therapy with radiolabeled phosphonates. Patients and Methods: Six patients (three male, three female; seven to 41 years) with unresectable primary osteosarcoma (n = 3) or unresectable recurrent sites of osteosarcomas (n = 3) were treated with high-activity of Sm-153-EDTMP (150 MBq/kg BW). In all patients autologous peripheral blood stem cells had been collected before Sm-153-EDTMP therapy. Results: No immediate adverse reactions were observed in the patients. In one patient bone pain increased during the first 48 hrs after therapy. Three patients received pain relief. Autologous peripheral blood stem cell reinfusion was performed on day +12 to +27 in all patients to overcome potentially irreversible damage to the hematopoietic stem cells. In three patient external radiotherapy of the primary tumor site was performed after Sm-153-EDTMP therapy and in two of them polychemotherapy was continued. Thirty-six months later one of these patients is still free of progression. Two further patients are still alive. However, they have developed new metastases. The three patients who had no accompanying external radiotherapy, all died of disease progression five to 20 months after therapy. Conclusion: These preliminary results show that high-dose Sm-153-EDTMP therapy is feasible and warrants further evaluation of efficacy. The combination with external radiation and polychemotherapy seems to be most promising. Although osteosarcoma is believed to be relatively radioresistant, the total focal dose achieved may delay local progression or even achieve permanent local tumor control in patients with surgically inaccessible primary or relapsing tumors.

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