scholarly journals The Deoxygenation of Jatropha Oil to High Quality Fuel via the Synergistic Catalytic Effect of Ni, W2C and WC Species

Catalysts ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 469
Author(s):  
Keyao Zhou ◽  
Xiangze Du ◽  
Linyuan Zhou ◽  
Huiru Yang ◽  
Xiaomei Lei ◽  
...  
Keyword(s):  
Particle Size ◽  
Synergistic Effect ◽  
Tungsten Carbide ◽  
Active Sites ◽  
Catalytic Effect ◽  
Catalytic Performance ◽  
Reduction Temperature ◽  
Jatropha Oil ◽  
High Quality ◽  
Nickel Tungsten

Tungsten carbide-based materials have good deoxygenation activity in the conversion of biomass. In this paper, catalysts with different nickel–tungsten carbide species were prepared by tuning the reduction temperature and Ni loading, and the effects of these different tungsten carbide species in the conversion of jatropha oil were studied. XRD, XPS, TEM, HRTEM, Raman, H2-TPR, ICP-AES were used to characterize the catalysts. The results suggested that metallic W was gradually carburized to W2C species, and W2C species was further carburized to WC species with the increase in reduction temperature and Ni loading. The obtained 10Ni10W/AC-700 catalyst exhibited outstanding catalytic performance with 99.7% deoxygenation rate and 94.5% C15-18 selectivity, which were attributed to the smallest particle size, the best dispersion, the most exposed active sites, and the synergistic effect of Ni, W2C and WC species.

Fast identification of stability of atomically dispersed bi-atom catalysts by a structure descriptor-based model

2022 ◽  
Author(s):  
Danyang LI ◽  
Haoxiang Xu ◽  
Jiqin Zhu ◽  
Dapeng Cao
Keyword(s):  
Synergistic Effect ◽  
Active Sites ◽  
Catalytic Performance ◽  
Fast Identification ◽  
Structure Descriptor

Atomically dispersed bi-atom catalysts (BACs) exhibit remarkable catalytic performance in a variety of reactions due to the adjacent coordination-unsaturated metal active sites, as well as interatomic synergistic effect. However, high-efficiently...

Liquid-Phase Selective Hydrogenation of Nitrobenzene over Ultrasonic-Assisted Ni-Mo-P Amorphous Catalyst

2012 ◽  
Vol 550-553 ◽  
pp. 420-423 ◽  
Author(s):  
Qian Wen Dai ◽  
Zi Li Liu ◽  
Cui Xia Xu ◽  
Qi Gang Xie ◽  
Fan Zhang ◽  
...  
Keyword(s):  
Particle Size ◽  
Liquid Phase ◽  
Selective Hydrogenation ◽  
Active Sites ◽  
Reduction Method ◽  
Chemical Reduction ◽  
Catalytic Performance ◽  
Chemical Reduction Method ◽  
Ultrasonic Assisted ◽  
Optimal Reaction

The Ni-Mo-P amorphous catalysts were prepared by chemical reduction method under different sonication conditions. The catalytic performance of the prepared catalysts in selective hydrogenation of nitrobenzene(NB) to aniline(AN) were characterized by XRD, BET, N2-adsorption, H2-TPR and H2-TPD. The results show that the introduction of ultrasonic can improve the dispersion of the active sites in the catalyst, the particle size of the catalyst is also smaller than the regular prepared Ni-Mo-P amorphous catalyst. And the influences of the sonication power and time on the catalysts were discussed and compared. The optimal sonication condition is 70 W within 25 min, its optimal reaction time is 150 min.

Hollow tungsten carbide/carbon sphere promoted Pt electrocatalyst for efficient methanol oxidation

RSC Advances ◽  
2015 ◽  
Vol 5 (9) ◽  
pp. 6790-6796 ◽  
Author(s):  
Zaoxue Yan ◽  
Fan Li ◽  
Jimin Xie ◽  
Xuli Miu
Keyword(s):  
Particle Size ◽  
Synergistic Effect ◽  
Tungsten Carbide ◽  
Methanol Oxidation ◽  
Noble Metal ◽  
Carbon Sphere ◽  
Surface Carbon

The surface carbon thickness and particle size of tungsten carbide (WC) are critical to its synergistic effect on noble metal based electrocatalysts.

The design and catalytic performance of molybdenum active sites on an MCM-41 framework for the aerobic oxidation of 5-hydroxymethylfurfural to 2,5-diformylfuran

2019 ◽  
Vol 9 (3) ◽  
pp. 811-821 ◽  
Author(s):  
Zhao-Meng Wang ◽  
Li-Juan Liu ◽  
Bo Xiang ◽  
Yue Wang ◽  
Ya-Jing Lyu ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Active Sites ◽  
Aerobic Oxidation ◽  
Catalytic Performance ◽  
Mcm 41

The catalytic activity decreases as –(SiO)3Mo(OH)(O) > –(SiO)2Mo(O)2 > –(O)4–MoO.

Catalytic Resonance Theory: Parallel Reaction Pathway Control

2019 ◽  
Author(s):  
M. Alexander Ardagh ◽  
Manish Shetty ◽  
Anatoliy Kuznetsov ◽  
Qi Zhang ◽  
Phillip Christopher ◽  
...  
Keyword(s):  
Chemical Reactions ◽  
Active Site ◽  
Active Sites ◽  
Reaction Pathway ◽  
Control Strategies ◽  
Oscillation Amplitude ◽  
Catalytic Performance ◽  
Parallel Reaction ◽  
Resonance Theory ◽  
Static Conditions

Catalytic enhancement of chemical reactions via heterogeneous materials occurs through stabilization of transition states at designed active sites, but dramatically greater rate acceleration on that same active site is achieved when the surface intermediates oscillate in binding energy. The applied oscillation amplitude and frequency can accelerate reactions orders of magnitude above the catalytic rates of static systems, provided the active site dynamics are tuned to the natural frequencies of the surface chemistry. In this work, differences in the characteristics of parallel reactions are exploited via selective application of active site dynamics (0 < ΔU < 1.0 eV amplitude, 10<sup>-6</sup> < f < 10<sup>4</sup> Hz frequency) to control the extent of competing reactions occurring on the shared catalytic surface. Simulation of multiple parallel reaction systems with broad range of variation in chemical parameters revealed that parallel chemistries are highly tunable in selectivity between either pure product, even when specific products are not selectively produced under static conditions. Two mechanisms leading to dynamic selectivity control were identified: (i) surface thermodynamic control of one product species under strong binding conditions, or (ii) catalytic resonance of the kinetics of one reaction over the other. These dynamic parallel pathway control strategies applied to a host of chemical conditions indicate significant potential for improving the catalytic performance of many important industrial chemical reactions beyond their existing static performance.

Structural/Texture Evolution During Facile Substitution of Ni into ZSM-5 Nanostructure vs. its Impregnation Dispersion Used in Selective Transformation of Methanol to Ethylene and Propylene

2020 ◽  
Vol 23 ◽  
Author(s):  
Parisa Sadeghpour ◽  
Mohammad Haghighi ◽  
Mehrdad Esmaeili
Keyword(s):  
High Temperature ◽  
Physicochemical Properties ◽  
Active Sites ◽  
Catalytic Performance ◽  
Fixed Bed Reactor ◽  
Light Olefins ◽  
Isomorphous Substitution ◽  
Impregnation Method ◽  
Hydrothermal Temperature ◽  
X Ray

Aim and Objective: Effect of two different modification methods for introducing Ni into ZSM-5 framework was investigated under high temperature synthesis conditions. The nickel successfully introduced into the MFI structures at different crystallization conditions to enhance the physicochemical properties and catalytic performance. Materials and Methods: A series of impregnated Ni/ZSM-5 and isomorphous substituted NiZSM-5 nanostructure catalysts were prepared hydrothermally at different high temperatures and within short times. X-ray diffraction (XRD), Field emission scanning electron microscopy (FESEM), Energy dispersive X-ray (EDX), Brunner, Emmett and Teller-Barrett, Joyner and Halenda (BET-BJH), Fourier transform infrared (FTIR) and Temperature-programmed desorption of ammonia (TPDNH3) were applied to investigate the physicochemical properties. Results: Although all the catalysts showed pure silica MFI–type nanosheets and coffin-like morphology, using the isomorphous substitution for Ni incorporation into the ZSM-5 framework led to the formation of materials with lower crystallinity, higher pore volume and stronger acidity compared to using impregnation method. Moreover, it was found that raising the hydrothermal temperature increased the crystallinity and enhanced more uniform incorporation of Ni atoms in the crystalline structure of catalysts. TPD-NH3 analysis demonstrated that high crystallization temperature and short crystallization time of NiZSM-5(350-0.5) resulted in fewer weak acid sites and medium acid strength. The MTO catalytic performance was tested in a fixed bed reactor at 460ºC and GHSV=10500 cm3 /gcat.h. A slightly different reaction pathway was proposed for the production of light olefins over impregnated Ni/ZSM-5 catalysts based on the role of NiO species. The enhanced methanol conversion for isomorphous substituted NiZSM-5 catalysts could be related to the most accessible active sites located inside the pores. Conclusion: The impregnated Ni/ZSM-5 catalyst prepared at low hydrothermal temperature showed the best catalytic performance, while the isomorphous substituted NiZSM-5 prepared at high temperature was found to be the active molecular sieve regarding the stability performance.

Positive Role of Synthesis Method and Hard Template on the Catalytic Performance of SAPO-34 in Methanol to Olefin Reaction.

2020 ◽  
Vol 23 ◽  
Author(s):  
Sajjad Rimaz ◽  
Reza Katal
Keyword(s):  
Particle Size ◽  
Synthesis Method ◽  
Catalytic Performance ◽  
Hard Template ◽  
Structure Directing Agent ◽  
Positive Role ◽  
Methanol To Olefin ◽  
Dg Method ◽  
Synthesis Procedure

: In the present study, SAPO-34 particles were synthesized using hydrothermal (HT) and dry gel (DG) conversion methods in the presence of diethyl amine (DEA) as an organic structure directing agent (SDA). Carbon nanotubes (CNT) were used as hard template in the synthesis procedure to introduce transport pores into the structures of the synthesized samples. The synthesized samples were characterized with different methods to reveal effects of synthesis method and using hard template on their structure and catalytic performance in methanol to olefin reaction (MTO). DG conversion method results in smaller particle size in comparison with hydrothermal method, resulting in enhancing catalytic performance. On the other side, using CNT in the synthesis procedure with DG method results in more reduction in particle size and formation of hierarchical structure which drastically improves catalytic performance.

Efficient Production of Biodiesel Catalyzed by Acidic Nanoporous Carbon Materials：A Review

2020 ◽  
Vol 16 ◽  
Author(s):  
Anping Wang ◽  
Heng Zhang ◽  
Hu Li ◽  
Song Yang
Keyword(s):  
Pore Structure ◽  
Active Sites ◽  
Catalytic Performance ◽  
Nanoporous Carbon ◽  
Biodiesel Production ◽  
Efficient Production ◽  
Fossil Energy ◽  
Catalytic Materials ◽  
High Acid ◽  
Carbon Based

Background: With the gradual decrease of fossil energy, the development of alternatives to fossil energy has attracted more and more attention. Biodiesel is considered to be the most potent alternative to fossil energy, mainly due to its green, renewable and biodegradable advantages. The stable, efficient and reusable catalysts are undoubtedly the most critical in the preparation of biodiesel. Among them, nanoporous carbon-based acidic materials are very important biodiesel catalysts. Objective: The latest advances of acidic nanoporous carbon catalysts in biodiesel production was reviewed. Methods: Biodiesel is mainly synthesized by esterification and transesterification. Due to the important role of nanoporous carbon-based acidic materials in the catalytic preparation of biodiesel, we focused on the synthesis, physical and chemical properties, catalytic performance and reusability. Results: Acidic catalytic materials have a good catalytic performance for high acid value feedstocks. However, the preparation of biodiesel with acid catalyst requires relatively strict reaction conditions. The application of nanoporous acidic carbon-based materials, due to the support of carbon-based framework, makes the catalyst have good stability and unique pore structure, accelerates the reaction mass transfer speed and accelerates the reaction. Conclusion: Nanoporous carbon-based acidic catalysts have the advantages of suitable pore structure, high active sites, and high stability. In order to make these catalytic processes more efficient, environmentally friendly and low cost, it is an important research direction for the future biodiesel catalysts to develop new catalytic materials with high specific surface area, suitable pore size, high acid density, and excellent performance.

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