Preparation and polishing properties of water-based magnetorheological chemical finishing fluid with high catalytic activity for single-crystal SiC

2020 ◽  
pp. 1045389X2097550
Author(s):  
Jiayun Deng ◽  
Jiabin Lu ◽  
Qiusheng Yan ◽  
Qixiang Zhang ◽  
Jisheng Pan
Keyword(s):  
Catalytic Activity ◽  
Single Crystal ◽  
Removal Rate ◽  
Catalytic Performance ◽  
Composite Catalyst ◽  
High Catalytic Activity ◽  
Chemical Action ◽  
Composite Catalysts ◽  
Water Based ◽  
Single Crystal Sic

A water-based high catalytic activity magnetorheological chemical finishing fluid (HCAMRCFF) was prepared and modified to enhance the chemical action strength in magnetorheological chemical finishing (MRCF) for single-crystal SiC. The fluid consisted of ferroferric oxide (Fe3O4) and chromium (Cr), deionized water (DW), polyethylene glycol (PEG) and oleic acid, and hydrogen peroxide (H2O2) as the composite catalyst particles, base carrier liquid, surfactants, and oxidant, respectively. HCAMRCFFs with different component concentrations were used to modify via evaluating their catalytic activity. Moreover, the MRCF experiments on SiC were conducted using the prepared HCAMRCFFs. The results show that the catalytic activity increases with an increase in the oxidant concentration. Furthermore, composite catalysts and composite surfactants can significantly improve their catalytic activity. The catalytic activity also increases with an increase in the concentration of composite catalysts. In the composite catalysts, increasing the Cr concentration can significantly enhance the catalytic performance. Composite surfactants can exert the relative superiority to enhance the catalytic activity. Compared with the unmodified finishing fluid, the catalytic activity of modified HCAMRCFF increases by 65.4%; the material removal rate (MRR) of SiC increases by 72.5% up to 635.621 nmh−1, and a surface with a roughness of 0.33 nm is obtained.

Facile preparation of a hierarchically porous metal–organic nanocomposite with excellent catalytic performance

RSC Advances ◽  
2016 ◽  
Vol 6 (99) ◽  
pp. 97399-97403 ◽  
Author(s):  
Rui Kuang ◽  
Luyi Zheng ◽  
Ethan Cottrill ◽  
Ning Pan ◽  
Yanhui Chi ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Aging Process ◽  
Porous Metal ◽  
Catalytic Performance ◽  
High Catalytic Activity ◽  
Hierarchically Porous ◽  
Hierarchical Porous ◽  
Metal Organic ◽  
Facile Preparation ◽  
Excellent Catalytic Performance

A hierarchical porous MOF nanocrystal, hpCuL (L = 2,4,6-tris(3,5-dicarboxylatephenylamino)-1,3,5-triazine) was prepared via a facile gel-aging process. This nanocomposite exhibits high catalytic activity and stability for the reduction of 4-nitrophenol.

Catalytic Wet Oxidating Fulvic Acid By Zero-Valent Copper Chitosan Activated Carbon Ball: Plackett-Buiman Design and Response Surface Modeling Optimization

2021 ◽  
Author(s):  
Chaofei Song ◽  
Yue Lv ◽  
Xia Qin ◽  
Jiaxin Cui ◽  
Chengrui Guo ◽  
...  
Keyword(s):  
Activated Carbon ◽  
Fulvic Acid ◽  
Response Surface ◽  
Removal Rate ◽  
Catalytic Performance ◽  
High Catalytic Activity ◽  
Catalytic Wet Oxidation ◽  
Experimental Conditions ◽  
Statistical Tool ◽  
Average Maximum

Abstract In this paper, the active component zero-valent copper (ZVC) supported by chitosan activated carbon ball (CTS-ACB) (i.e. ZVC/CTS-ACS catalyst) was successfully prepared. The characterization results showed obvious characteristics of activated carbon and zero-valent copper. The catalyst was used to degrade fulvic acid (FA) in catalytic wet oxidation(CWO) system. The two significant factors acidity and temperature were found with the statistical tool Plackett-Buimanhe(PB) in CWO for FA removal. Then the response surface methodology(RSM) model was used to optimize the experimental conditions in order to obtain the optimal FA removal rate. With the optimal experimental parameters, that is, a temperature of 94°C and an acidity of 3.8, the average maximum removal rate of FA was 93.02%, which was in agreement with the expected result of the model 93.86%, indicating that the model is well established. The comparison of catalytic performance showed that the addition of catalyst ZVC / CTS-ACS could increase the removal rate of FA, colour number(CN) and TOC by 93.6%, 83.5% and 81.9% respectively. The utilization of ZVC can greatly increase the mineralization rate of FA , which indicates the high catalytic activity and minerazation of the catalyst.

Influence of lattice oxygen on properties of Ce–Fe composite in NO+CO reduction system

2020 ◽  
Vol 10 (8) ◽  
pp. 1292-1299
Author(s):  
Yuze Bai ◽  
Huizhong Wu ◽  
Jinhao Zhu ◽  
Lichao Yang ◽  
Na Li ◽  
...  
Keyword(s):  
Solid Solution ◽  
Hydrothermal Method ◽  
Fine Particles ◽  
Lattice Oxygen ◽  
Composite Catalyst ◽  
Ferric Nitrate ◽  
High Catalytic Activity ◽  
Composite Catalysts ◽  
Reduction System ◽  
Co Reduction

Ce–Fe composite was prepared by hydrothermal method to simulate the ore facies with Ce–Fe coatingembedded structure in rare earth tailings. Fe2O3 is used as the carrier and cerium nitrate is used as active component. We studied the effect of lattice oxygen on the performance of Ce–Fe composites in the NO+CO reduction system. The results show that the peak of CeO2 in the sample prepared by the hydrothermal method of nitric acid moves at a high angle, the lattice constant becomes smaller, and the diffraction peak corresponding to CeO2 in Raman is red-shifted. It indicated that the hydrothermal method can form Ce–O–Fe solid solution. In TEM, nanoscale Fe2O3 particles caused by the decomposition of ferric nitrate were observed on the surface of the sample. In the whole reaction process, a large amount of lattice oxygen provided by Fe2O3 as a carrier, the presence of Ce–O–Fe solid solution and free Fe2O3 fine particles determine the high catalytic activity of the composite catalyst. The presence of CeO2 can improve the surface reduction of Fe2O3, and also promote the conversion of Fe3+ to Fe2+, Ce4+ to Ce3+. The conversion of lattice oxygen to adsorbed oxygen reflects the combined action of the composite catalysts Ce and Fe. The denitration rate of the Ce–Fe composite NO+CO reduction system exceeded 92.24% at 700 °C. Lattice oxygen can promote the performance of Ce–Fe composites in NO+CO reduction system.

MOF-derived Co1.11Te2 with half-metallic character for efficient photochemical conversion of CO2 under visible-light irradiation

2019 ◽  
Vol 55 (48) ◽  
pp. 6862-6865 ◽  
Author(s):  
Yong Xu ◽  
Jiang Mo ◽  
Guanqun Xie ◽  
Dawei Ding ◽  
Shujiang Ding ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Catalytic Activity ◽  
Energy Barrier ◽  
Catalytic Performance ◽  
Carbon Layer ◽  
Low Energy ◽  
High Catalytic Activity ◽  
Key Factors ◽  
Strong Electron ◽  
Half Metallic

Co1.11Te2 enwrapped in a carbon layer displayed high catalytic performance for photocatalytic CO2 reduction. The strong electron transfer ability and the low energy barrier are the key factors that promote its high catalytic activity.

scholarly journals Biodiesel Production over Niobium-Containing Catalysts: A Review

Energies ◽  
2021 ◽  
Vol 14 (17) ◽  
pp. 5506
Author(s):  
Daniel Carreira Batalha ◽  
Márcio José da Silva
Keyword(s):  
Catalytic Activity ◽  
Active Sites ◽  
Heterogeneous Catalysts ◽  
Raw Materials ◽  
Catalytic Performance ◽  
High Specific Surface Area ◽  
Biodiesel Production ◽  
Molar Ratio ◽  
Main Reaction ◽  
High Catalytic Activity

Nowadays, the synthesis of biofuels from renewable raw materials is very popular. Among the various challenges involved in improving these processes, environmentally benign catalysts compatible with an inexpensive feedstock have become more important. Herein, we report the recent advances achieved in the development of Niobium-containing heterogeneous catalysts as well as their use in routes to produce biodiesel. The efficiency of different Niobium catalysts in esterification and transesterification reactions of lipids and oleaginous raw materials was evaluated, considering the effect of main reaction parameters such as temperature, time, catalyst load, and oil:alcohol molar ratio on the biodiesel yield. The catalytic performance of Niobium compounds was discussed considering the characterization data obtained by different techniques, including NH3-TPD, BET, and Pyr-FT-IR analysis. The high catalytic activity is attributed to its inherent properties, such as the active sites distribution over a high specific surface area, strength of acidity, nature, amount of acidic sites, and inherent mesoporosity. On top of this, recycling experiments have proven that most Niobium catalysts are stable and can be repeatedly used with consistent catalytic activity.

scholarly journals Properties and catalytic performance of sulphate-vanadia impregnated fumed silica as oxidative catalyst

2015 ◽  
Vol 11 (2) ◽  
Author(s):  
Nor Masdiana Zulkeple ◽  
Norhasyimah Mohd Kamal ◽  
Jamilah Mohd Ekhsan ◽  
Salasiah Che Me ◽  
Swee Ean Lim ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Catalytic Activity ◽  
Charge Transfer ◽  
Surface Area ◽  
Sulphuric Acid ◽  
Fumed Silica ◽  
Catalytic Performance ◽  
Support Surface ◽  
High Catalytic Activity ◽  
Impregnation Method

A series of sulphate-vanadia impregnated fumed silica oxidative catalysts were synthesized via impregnation method. The samples were prepared by impregnation of 1 wt% of vanadium and 0.2 M of sulphuric acid onto fumed silica as support. Surface area of the silica supported samples were similar of 118 m2/g. UV-Vis DRS results showed existence of o supported V species and the charge transfer bands associated with O2- to V5+ in tetrahedral environments. Catalytic performance were evaluated via epoxidation of 1-octene to 1,2-epoxyoctane using hydrogen peroxide as an oxidant. It had been demonstrated that sulphate-vanadia impregnated fumed silica had high catalytic activity of 626 ± 0.2 mmol epoxide was produced after 24 h reaction. This may indicate that more oxidative sites were generated after the impregnation of V and sulphate onto the SiO2 matrixes.

Pd nanoparticles stabilized with phosphine-functionalized porous ionic polymer for efficient catalytic hydrogenation of nitroarenes in water

2020 ◽  
Vol 44 (9) ◽  
pp. 3681-3689 ◽  
Author(s):  
Yizhu Lei ◽  
Zaifei Chen ◽  
Guosong Lan ◽  
Renshu Wang ◽  
Xiao-Yu Zhou
Keyword(s):  
Catalytic Activity ◽  
Catalytic Hydrogenation ◽  
Palladium Nanoparticles ◽  
Pd Nanoparticles ◽  
Catalytic Performance ◽  
High Catalytic Activity ◽  
Ionic Polymer ◽  
Electron Donation ◽  
Nano Size ◽  
Excellent Catalytic Performance

Small palladium nanoparticles stabilized with phosphine-functionalized PIP displayed high catalytic activity for nitroarenes hydrogenation. Nano-size Pd particles, electron-donation effect of phosphine ligand, and surface wettability account for its excellent catalytic performance.

Syntheses and structures of two gold(i) coordination compounds derived from P–S hybrid ligands and their efficient catalytic performance in the photodegradation of nitroaromatics in water

2015 ◽  
Vol 44 (12) ◽  
pp. 5662-5671 ◽  
Author(s):  
Hai-Xiao Qi ◽  
Jian-Feng Wang ◽  
Zhi-Gang Ren ◽  
Jin-Jiao Ning ◽  
Jian-Ping Lang
Keyword(s):  
Catalytic Activity ◽  
Coordination Compounds ◽  
Catalytic Performance ◽  
High Catalytic Activity ◽  
Hybrid Ligands

Two Au–P–S complexes [Au2(dppatc)2]Cl2 and [Au(dppmt)]2 were prepared and they showed high catalytic activity toward the photodegradation of nitroaromatics in water.

Preparation of NixCo3-xTiO4 Ternary Nanowire and Study on their Electrocatalytic Performances

2017 ◽  
Vol 1142 ◽  
pp. 197-200
Author(s):  
Xiao Bo Zhang ◽  
Hai Ping Liu
Keyword(s):  
Cyclic Voltammetry ◽  
Catalytic Activity ◽  
Steady State ◽  
Anode Materials ◽  
Catalytic Performance ◽  
High Catalytic Activity ◽  
Deposition Method ◽  
Good Crystallinity ◽  
Constant Potential ◽  
Cobalt And Nickel

In this paper, NixCo3-xTiO4 nanowire as anode materials was prepared by co-deposition method, and the characterized results showed that had good crystallinity by SEM. The cobalt and nickel were enriched in the surface in the sample by XPS. The catalytic performance of NixCo3-xTiO4 was studied by cyclic voltammetry and constant potential. The results showed that when the Co: Ni = 4:1, the temperature was 120°C, NixCo3-xTiO4 nanowires had high catalytic activity and good stability by the cyclic voltammetry and the steady state polarization curves.

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