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.

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.

Effect of Bi and In on Microstructure Formation in Sn-3Ag-3Bi-3In/Cu and /Ni Solder Joints

2016 ◽  
Vol 700 ◽  
pp. 142-151 ◽  
Author(s):  
Sergey A. Belyakov ◽  
Christopher M. Gourlay
Keyword(s):  
Solid Solution ◽  
Phase Equilibria ◽  
Ternary Compound ◽  
Fine Particles ◽  
Solder Joints ◽  
Primary Phase ◽  
Significant Fraction ◽  
Microstructure Formation ◽  
Five Phases

Sn-3Ag-3Bi-3In solder has been investigated to improve the understanding of microstructure formation in this solder during solidification and soldering to Cu and Ni substrates. The as-solidified microstructures of Sn-3Ag-3Bi-3In samples were found to consist of a significant fraction of βSn dendrites with a complex eutectic between the dendrites. In total five phases were observed to form during solidification: βSn, Ag3Sn, Bi, ζAg and a “Sn-In-Bi” ternary compound. Soldering of Sn-3Ag-3Bi-3In to substrates changed the phase equilibria in the system and caused the formation of additional phases: Cu6Sn5 during soldering to Cu and Ni3Sn4 and metastable NiSn4 during soldering to Ni. It is shown that metastable NiSn4 forms as a primary phase in a complex 5-component Sn-3Ag-3Bi-3In-Ni system. In and Bi were detected in solid solution in the βSn matrix in amounts of ~1.5-2at% and ~1.2at% respectively. Bi also existed as fine particles of two distinct types. (i): sub-micron (<500nm) coral-like particles and (ii) facetted particles measuring up to 7-8 μm.

The selective catalytic reduction of NOx over a Cu/ZSM-5/SAPO-34 composite catalyst

RSC Advances ◽  
2015 ◽  
Vol 5 (127) ◽  
pp. 104923-104931 ◽  
Author(s):  
Jixing Liu ◽  
Weiyu Song ◽  
Chi Xu ◽  
Jian Liu ◽  
Zhen Zhao ◽  
...  
Keyword(s):  
Selective Catalytic Reduction ◽  
Mass Fraction ◽  
Catalytic Reduction ◽  
Composite Catalyst ◽  
Composite Catalysts ◽  
Scr Of No ◽  
Reduction Of Nox ◽  
Seed Method ◽  
Catalytic Performances

A series of Cu/ZSM-5/SAPO-34 composite catalysts with varying ZSM-5 mass fraction were synthesized using a pre-seed method, and their catalytic performances were tested for selective catalytic reduction (SCR) of NO with NH3.

scholarly journals Impact of support characteristics and preparation method on photocatalytic activity of TiO 2 /ZSM-5/silica gel composite photocatalyst

2018 ◽  
Vol 5 (9) ◽  
pp. 180918 ◽  
Author(s):  
Emad K. Radwan ◽  
Cooper H. Langford ◽  
Gopal Achari
Keyword(s):  
Silica Gel ◽  
Photocatalytic Oxidation ◽  
Preparation Method ◽  
Light Emitting Diode ◽  
Synergetic Effect ◽  
Silica Gels ◽  
Composite Catalyst ◽  
Composite Catalysts ◽  
Photocatalytic Ozonation ◽  
Degussa P25

Titanium dioxide (Degussa P25) was supported onto two different aluminosilicate zeolites (ZSM-5) and anchored on three silica gels using two separate preparation methods to study the effect of the catalyst components and the preparation method on the photoactivity of composite catalysts. The photoactivity was investigated by tracking phenol disappearance in a batch UVA light-emitting diode reactor. An easily separable photocatalyst with higher photoactivity than commercial Degussa P25 was developed using Degussa P25, ZSM-5 (SiO 2 /Al 2 O 3 = 280) and silica gel (particle size 0.2–0.5 mm and pore size 40 Å). The optimum composition was found to be P25:ZSM-5:silica gel = 0.3 : 0.5 : 0.5 g l −1 . SEM photographs show that the distribution of the composite catalyst components prepared without a binder was better than that prepared with a binder. The efficiency of photocatalytic ozonation of sulfamethoxazole (SMX) using the new photocatalyst was assessed and compared to that of commercially available Degussa P25. It was found that photocatalytic ozonation promoted the SMX disappearance and mineralization. PZS was superior to Degussa P25 with respect to photocatalysis and photocatalytic ozonation. The enhancement was attributed to the synergetic effect between adsorption, ozonation and/or photocatalytic oxidation.

Efficient visible-light-induced hydrogen evolution from water splitting using a nanocrystalline nickel phosphide catalyst

RSC Advances ◽  
2016 ◽  
Vol 6 (29) ◽  
pp. 24361-24365 ◽  
Author(s):  
Weiming Wu ◽  
Xianyang Yue ◽  
Xiao-Yuan Wu ◽  
Can-Zhong Lu
Keyword(s):  
Catalytic Activity ◽  
Visible Light ◽  
Hydrothermal Method ◽  
Hydrogen Evolution ◽  
Water Splitting ◽  
Visible Light Irradiation ◽  
Light Irradiation ◽  
Good Stability ◽  
High Catalytic Activity ◽  
Nickel Phosphide

Nanocrystalline Ni12P5 was synthesized by a simple hydrothermal method. It showed high catalytic activity (10 760 μmol h−1 g−1, TOF = 9.3 h−1) and good stability (15 h) for the hydrogen evolution from water under visible light irradiation.

An efficient ultra-thin chain-structured copper cobalt oxide/sulfide composite catalyst for electrochemical hydrogen generation

RSC Advances ◽  
2016 ◽  
Vol 6 (49) ◽  
pp. 43185-43190 ◽  
Author(s):  
Yudong Gong ◽  
Yang Zhao ◽  
Yujin Chen ◽  
Yizhi Wang ◽  
Chunwen Sun
Keyword(s):  
Hydrothermal Method ◽  
Cobalt Oxide ◽  
Hydrogen Generation ◽  
Composite Catalyst

An ultra-thin chain-structured copper cobalt oxide/sulfide composite catalyst was prepared by hydrothermal method for HER.

Highly selective catalytic conversion of phenols to aromatic hydrocarbons on CoS2/MoS2 synthesized using a two step hydrothermal method

RSC Advances ◽  
2016 ◽  
Vol 6 (37) ◽  
pp. 31265-31271 ◽  
Author(s):  
Weiyan Wang ◽  
Lu Li ◽  
Kui Wu ◽  
Guohua Zhu ◽  
Song Tan ◽  
...  
Keyword(s):  
Hydrothermal Method ◽  
Aromatic Hydrocarbons ◽  
Catalytic Conversion ◽  
Composite Catalysts ◽  
Very High

CoS2/MoS2 composite catalysts were synthesized by two-step hydrothermal method and presented very high hydrodeoxygenation and direct deoxygenation activity in phenols conversion.

Preparation, Characterization and Effectivity of N, Fe-TiO2 as a Visible Light Active Photocatalyst

2014 ◽  
Vol 894 ◽  
pp. 245-249 ◽  
Author(s):  
Arman Sikirman ◽  
Jagannathan Krishnan ◽  
Junaidah Jai ◽  
Senusi Faraziehan
Keyword(s):  
Methylene Blue ◽  
Titanium Dioxide ◽  
Visible Light ◽  
Fine Particles ◽  
Irradiation Time ◽  
Anatase Phase ◽  
Titanium Isopropoxide ◽  
Ferric Nitrate ◽  
Co Doping ◽  
Sem Image

Surface modification of the titanium dioxide by doping and co-doping with nitrogen and iron in order to make the photocatalyst active under visible light was investigated. Solgel method was adapted for the preparation of surface modified titanium dioxide, where tetra titanium isopropoxide, ammonium nitrate and ferric nitrate were used as precursors while maintaining the dopant concentration and calcination temperature at 0.75% and 600°C, respectively. The prepared photocatalyst samples were characterized by XRD, FE-SEM and FTIR in order to study their physical properties. The results from XRD confirmed that all prepared photocatalyst were of anatase phase. FE-SEM image analysis revealed the formation of fine particles and the FTIR analysis verified the presence of dopants. The effectivity of photocatalysts was tested by performing a standard batch photocatalytic degradation experiment with methylene blue as a model pollutant under visible light. The result showed that co-doped photocatalyst (0.75% N, 075% Fe-TiO2-600) yielded a maximum of 76% methylene blue degraded within three hours of irradiation time.

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