scholarly journals Effect of Copper Nanoparticles Dispersion on Catalytic Performance of Cu/SiO2Catalyst for Hydrogenation of Dimethyl Oxalate to Ethylene Glycol

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Yajing Zhang ◽  
Na Zheng ◽  
Kangjun Wang ◽  
Sujuan Zhang ◽  
Jing Wu
Keyword(s):  
Ethylene Glycol ◽  
Copper Nanoparticles ◽  
Photoelectron Spectroscopy ◽  
Sol Gel ◽  
Catalytic Performance ◽  
Bet Surface Area ◽  
X Ray ◽  
Dimethyl Oxalate ◽  
Effect Of Copper ◽  
Average Size

Cu/SiO2catalysts, for the synthesis of ethylene glycol (EG) from hydrogenation of dimethyl oxalate (DMO), were prepared by ammonia-evaporation and sol-gel methods, respectively. The structure, size of copper nanoparticles, copper dispersion, and the surface chemical states were investigated by X-ray diffraction (XRD), transmission electron microscopy (TEM), temperature-programmed reduction (TPR), and X-ray photoelectron spectroscopy (XPS) and N2adsorption. It is found the structures and catalytic performances of the catalysts were highly affected by the preparation method. The catalyst prepared by sol-gel method had smaller average size of copper nanoparticles (about 3-4 nm), better copper dispersion, higher Cu+/C0ratio and larger BET surface area, and higher DMO conversion and EG selectivity under the optimized reaction conditions.

scholarly journals Synthesis and Catalytic Performance of Ni/SiO2for Hydrogenation of 2-Methylfuran to 2-Methyltetrahydrofuran

2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Fu Ding ◽  
Yajing Zhang ◽  
Guijin Yuan ◽  
Kangjun Wang ◽  
Ileana Dragutan ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Sol Gel ◽  
Catalytic Performance ◽  
Bet Surface Area ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ni Content ◽  
Transmission Electron ◽  
Temperature Programmed ◽  
Ni Species

A series of Ni/SiO2catalysts with different Ni content were prepared by sol-gel method for application in the synthesis of 2-methyltetrahydrofuran (2-MTHF) by hydrogenation of 2-methylfuran (2-MF). The catalyst structure was investigated by X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and temperature programmed reduction (TPR). It is found that structures and catalytic performance of the catalysts were highly affected by the Ni content. The catalyst with a 25% Ni content had an appropriate size of the Ni species and larger BET surface area and produced a higher 2-MF conversion with enhanced selectivity in 2-MTHF.

Preparation of Novel Ag–Si–TiO2 Composite and Research on Its Photocatalytic Degradation of Formaldehyde

2021 ◽  
Vol 13 (3) ◽  
pp. 371-380
Author(s):  
Yongjun Wu ◽  
Nina Xie ◽  
Lu Yu
Keyword(s):  
Photoelectron Spectroscopy ◽  
Removal Rate ◽  
Sol Gel ◽  
Catalytic Performance ◽  
Formaldehyde Concentration ◽  
Order Kinetic ◽  
Solution Ph ◽  
Visible Absorption ◽  
X Ray ◽  
Co Doped

A novel Ag–Si–TiO2 composite was prepared via sol–gel method for removing residual formaldehyde in shiitake mushroom. The structure of Ag–Si–TiO2 composite was characterized by scanning electron microscope (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analyses. Ultraviolet-visible absorption spectroscopy (UV-Vis) and N2 adsorption-desorption tests showed that Ag and Si co-doped decreased the band gap, the Brunauer-Emmett-Teller (BET) specific surface area of the samples increased and the recombination probability of electron-hole pairs (e--h+) reduced. Effect on removal rate of formaldehyde with different Ag-Si co-doped content, formaldehyde concentration and solution pH were investigated, and the results showed that 6.0 wt%Ag-3.0 wt%Si-TiO2 samples had an optimum catalytic performance, and the degradation efficiency reached 96.6% after 40 W 365 nm UV lamp irradiation for 360 min. The kinetics of formaldehyde degradation by Ag–Si–TiO2 composite photocatalyst could be described by Langmuir-Hinshelwood first-order kinetic model.

Synthesis of TiO2 and ZrO2 nanomaterials for the degradation of nerve agent simulants

2021 ◽  
Vol 11 (1) ◽  
pp. 105-110
Author(s):  
Dung Le Van ◽  
Phuong Dang Tuyet ◽  
Trinh Nguyen Duy ◽  
Manh Nguyen Ba
Keyword(s):  
Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
Sol Gel ◽  
Chemical Warfare Agent ◽  
Catalytic Performance ◽  
Sem Images ◽  
X Ray ◽  
Nitrophenyl Phosphate ◽  
Tio2 Nanomaterials ◽  
Adsorption Desorption

TiO2 and ZrO2 nanomaterials were successfully synthesized by sol gel method. Samples were characterized by X-ray difraction (XRD), Fourier-transform infrared spectroscopy (FTIR), N2 adsorption–desorption, Scanning electron microscopy (SEM), Transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS),  SEM images and TEM images of TiO2 and ZrO2 samples showed the particle size of 10–20 nm. The results have revealed highly porous structure of ZrO2 and TiO2 nanomaterials with specific surface area of 116 m2g-1 and 125 m2g-1, respectively. The TiO2 and ZrO2 materials were used as the degradation of dimethyl 4-nitrophenyl phosphate (DMNP) chemical warfare agent emulator. The ZrO2 nanomaterial exhibited highly catalytic performance of DMNP degradation and the conversion reached to the value of 90.64 %, after 120 min of reaction.

scholarly journals Preparation of Stellerite Loading Titanium Dioxide Photocatalyst and Its Catalytic Performance on Methyl Orange

2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Hua Chen ◽  
Jianhua Wang ◽  
Huajun Wang ◽  
Fei Yang ◽  
Jia-nan Zhou ◽  
...  
Keyword(s):  
Surface Area ◽  
Sol Gel ◽  
Catalytic Performance ◽  
Bet Surface Area ◽  
X Ray Diffraction ◽  
Photocatalytic Ability ◽  
X Ray ◽  
Composite Photocatalysts ◽  
Ft Ir ◽  
Better Than

TiO2/stellerite composite photocatalysts were prepared by dispersing TiO2 onto the surface of HCl, NaOH, or NaCl treated stellerite using a sol-gel method. The materials were characterized by scanning electron microscopy (SEM), energy dispersive X-ray (EDX), Fourier transform infrared spectroscopy (FT-IR), BET surface area analysis, and X-ray diffraction (XRD). HCl and NaCl modification result in the promotion of the pore formation at the stellerite surfaces and induced the microscopic changes, while the surface morphology and structure of the stellerite were almost ruined by NaOH modification. Supported TiO2 calcinated at 200°C presented anatase structure. The photocatalytic degradation activities of TiO2 loaded HCl and NaCl modified stellerite were better than that of natural stellerite, accompanied with increasing specific surface area. On the contrary, NaOH modification induced the loss of photocatalytic ability of composite due to the generation of silicates.

scholarly journals The Effect of Transition Metal Substitution in the Perovskite-Type Oxides on the Physicochemical Properties and the Catalytic Performance in Diesel Soot Oxidation

Catalysts ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1256
Author(s):  
Liliya V. Yafarova ◽  
Grigory V. Mamontov ◽  
Irina V. Chislova ◽  
Oleg I. Silyukov ◽  
Irina A. Zvereva
Keyword(s):  
Photoelectron Spectroscopy ◽  
Sol Gel ◽  
Simultaneous Thermal Analysis ◽  
Cobalt Content ◽  
Soot Oxidation ◽  
Substitution Effect ◽  
Catalytic Performance ◽  
Oxygen Mobility ◽  
X Ray ◽  
Temperature Programmed

The paper is focused on the Fe for Co substitution effect on the redox and catalytic properties in the perovskite structure of GdFeO3. The solid oxides with the composition GdFe1−xCoxO3 (x = 0; 0.2; 0.5; 0.8; 1) were obtained by the sol-gel method and characterized by various methods: X-Ray diffraction (XRD), temperature-programmed reduction (H2-TPR), N2 sorption, temperature-programmed desorption of oxygen (TPD-O2), simultaneous thermal analysis (STA), and X-ray photoelectron spectroscopy (XPS). The H2-TPR results showed that an increase in the cobalt content in the GdFe1−xCoxO3 (x = 0; 0.2; 0.5; 0.8; 1) leads to a decrease in the reduction temperature. Using the TPD-O2 and STA methods, the lattice oxygen mobility is increasing in the course of the substitution of Fe for Co. Thus, the Fe substitution in the perovskite leads to an improvement in the oxygen reaction ability. Experiments on the soot oxidation reveal that catalytic oxidation ability increases in the series: GdFe0.5Co0.5O3 ˂ GdFe0.2Co0.8O3 ˂ GdCoO3, which is in good correlation with the increasing oxygen mobility according to H2-TPR, TPD-O2, and STA results. The soot oxidation over GdFeO3 and GdFe0.8Co0.2O3 is not in this range due to the impurities of iron oxides and higher specific surface area.

scholarly journals Boron Modified Bifunctional Cu/SiO2 Catalysts with Enhanced Metal Dispersion and Surface Acid Sites for Selective Hydrogenation of Dimethyl Oxalate to Ethylene Glycol and Ethanol

Nanomaterials ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 3236
Author(s):  
Deliang Yang ◽  
Runping Ye ◽  
Ling Lin ◽  
Rong Guo ◽  
Peiyu Zhao ◽  
...  
Keyword(s):  
Low Temperature ◽  
Ethylene Glycol ◽  
Structural Characteristics ◽  
Sol Gel ◽  
Metallic Copper ◽  
Sample Surface ◽  
Catalytic Performance ◽  
Acid Sites ◽  
Dimethyl Oxalate ◽  
Metal Support Interaction

Boron (B) promoter modified Cu/SiO2 bifunctional catalysts were synthesized by sol-gel method and used to produce ethylene glycol (EG) and ethanol (EtOH) through efficient hydrogenation of dimethyl oxalate (DMO). Experimental results showed that boron promoter could significantly improve the catalytic performance by improving the structural characteristics of the Cu/SiO2 catalysts. The optimized 2B-Cu/SiO2 catalyst exhibited excellent low temperature catalytic activity and long-term stability, maintaining the average EG selectivity (Sel.EG) of 95% at 190 °C, and maintaining the average EtOH selectivity (Sel.EtOH) of 88% at 260 °C, with no decrease even after reaction of 150 h, respectively. Characterization results revealed that doping with boron promoter could significantly increase the copper dispersion, enhance the metal-support interaction, maintain suitable Cu+/(Cu+ + Cu0) ratio, and diminish metallic copper particles during the hydrogenation of DMO. Thus, this work introduced a bifunctional boron promoter, which could not only improve the copper dispersion, reduce the formation of bulk copper oxide, but also properly enhance the acidity of the sample surface, so that the Cu/SiO2 sample could exhibit superior EG selectivity at low temperature, as well as improving the EtOH selectivity at high temperature.

scholarly journals Catalytic performance of the Ce-doped LaCoO3 perovskite nanoparticles

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Anees A. Ansari ◽  
Syed F. Adil ◽  
Manawwer Alam ◽  
N. Ahmad ◽  
Mohamed E. Assal ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Oxygen Vacancies ◽  
Sol Gel ◽  
Nitrogen Adsorption ◽  
Catalytic Performance ◽  
Temperature Program Reduction ◽  
X Ray ◽  
Vis Spectroscopy ◽  
Optimum Reaction ◽  
Perovskite Nanoparticles

Abstract A series of La1-xCexCoO3 perovskite nanoparticles with rhombohedral phases was synthesized via sol–gel chemical process. X-ray diffraction (XRD), Transmission Electron Microscopy (TEM), Electron Diffraction Spectroscopy (EDS), Thermogravimetric Analysis (TGA), UV–Vis spectroscopy, Fourier Transform Infrared spectra (FTIR), Nitrogen Adsorption/desorption Isotherm, Temperature Program Reduction/Oxidation (TPR/TPO), X-ray Photoelectron Spectroscopy (XPS) techniques were utilized to examine the phase purity and chemical composition of the materials. An appropriate doping quantity of Ce ion in the LaCoO3 matrix have reduced the bond angle, thus distorting the geometrical structure and creating oxygen vacancies, which thus provides fast electron transportation. The reducibility character and surface adsorbed oxygen vacancies of the perovskites were further improved, as revealed by H2-TPR, O2-TPD and XPS studies. Furthermore, the oxidation of benzyl alcohol was investigated using the prepared perovskites to examine the effect of ceria doping on the catalytic performance of the material. The reaction was carried out with ultra-pure molecular oxygen as oxidant at atmospheric pressure in liquid medium and the kinetics of the reaction was investigated, with a focus on the conversion and selectivity towards benzaldehyde. Under optimum reaction conditions, the 5% Ce doped LaCoO3 catalyst exhibited enhanced catalytic activity (i.e., > 35%) and selectivity of > 99%, as compared to the other prepared catalysts. Remarkably, the activity of catalyst has been found to be stable after four recycles.

Copper Nanoparticles Deposited Cellulose Acetate Microfibers as Heterogenous Catalysts for 4-Nitrophenol Reduction in Aqueous Media

2019 ◽  
Vol 11 (5) ◽  
pp. 630-637
Author(s):  
Peng Xu ◽  
Changli Cen ◽  
Nannan Chen ◽  
Mengke Zheng ◽  
Zhenguo Wu ◽  
...  
Keyword(s):  
Cellulose Acetate ◽  
Copper Nanoparticles ◽  
Photoelectron Spectroscopy ◽  
Copper Chloride ◽  
Aqueous Media ◽  
Reduction Process ◽  
Catalytic Performance ◽  
Reusable Catalyst ◽  
X Ray ◽  
Nitrophenol Reduction

In this work, copper nanoparticles (CuNPs) loaded cellulose acetate microfibers (CAMFs-Cu) are successfully prepared as a novel heterogenous catalyst. For this purpose, the cellulose acetate microfibers (CAMFs) with a diameter of ca. 300–500 nm are fabricated by electrospinning method. Then, CuNPs are deposited onto the CAMFs via a convenient wet reduction process using copper chloride as precursor and sodium borohydride as reduction agent. The chemical composition of the fabricated CAMFs-Cu is characterized by energy dispersive X-ray (EDX) spectroscopy, powder X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). Scanning electron microscope (SEM) and transmission electron microscopy (TEM) images reveal that the CuNPs with a diameter of approximately 20 nm are homogenously deposited on the CAMFs. The distribution density for the CuNPs increases with precursor concentrations. The catalytic performance shows that the CAMFsCu lead to approximate 100% reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) and the reaction constant increases with deposited Cu content. The CAMFs-Cu heterogenous catalysts are very stable and could be reused up to eight times in consecutive runs without any treatment between the cycles. The CAMFs-Cu is thus expected to have great potential as a highly efficient, cost-effective and eco-friendly reusable catalyst for catalytic applications.

scholarly journals Enhanced Photocatalytic Activity of CuWO4 Doped TiO2 Photocatalyst Towards Carbamazepine Removal under UV Irradiation

Separations ◽  
2021 ◽  
Vol 8 (3) ◽  
pp. 25
Author(s):  
Chukwuka Bethel Anucha ◽  
Ilknur Altin ◽  
Emin Bacaksız ◽  
Tayfur Kucukomeroglu ◽  
Masho Hilawie Belay ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Photocatalytic Activity ◽  
Photoelectron Spectroscopy ◽  
Diffuse Reflectance Spectroscopy ◽  
Sol Gel ◽  
Pure Tio2 ◽  
Component Part ◽  
Energy Yield ◽  
Mechanical Agitation ◽  
X Ray

Abatement of contaminants of emerging concerns (CECs) in water sources has been widely studied employing TiO2 based heterogeneous photocatalysis. However, low quantum energy yield among other limitations of titania has led to its modification with other semiconductor materials for improved photocatalytic activity. In this work, a 0.05 wt.% CuWO4 over TiO2 was prepared as a powder composite. Each component part synthesized via the sol-gel method for TiO2, and CuWO4 by co-precipitation assisted hydrothermal method from precursor salts, underwent gentle mechanical agitation. Homogenization of the nanopowder precursors was performed by zirconia ball milling for 2 h. The final material was obtained after annealing at 500 °C for 3.5 h. Structural and morphological characterization of the synthesized material has been achieved employing X-ray diffraction (XRD), Fourier transform infra-red (FTIR) spectroscopy, Brunauer–Emmett–Teller (BET) N2 adsorption–desorption analysis, Scanning electron microscopy-coupled Energy dispersive X-ray spectroscopy (SEM-EDS), Transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and UV-Vis diffuse reflectance spectroscopy (UV-vis DRS) for optical characterization. The 0.05 wt.% CuWO4-TiO2 catalyst was investigated for its photocatalytic activity over carbamazepine (CBZ), achieving a degradation of almost 100% after 2 h irradiation. A comparison with pure TiO2 prepared under those same conditions was made. The effect of pH, chemical scavengers, H2O2 as well as contaminant ion effects (anions, cations), and humic acid (HA) was investigated, and their related influences on the photocatalyst efficiency towards CBZ degradation highlighted accordingly.

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