Characterization of Vanadia Sites in V-Silicalite, Vanadia-Silica Cogel, and Silica-Supported Vanadia Catalysts: X-Ray Powder Diffraction, Raman Spectroscopy, Solid-State51V NMR, Temperature-Programmed Reduction, and Methanol Oxidation Studies

1998 ◽  
Vol 178 (2) ◽  
pp. 640-648 ◽  
Author(s):  
Chuan-Bao Wang ◽  
Goutam Deo ◽  
Israel E. Wachs
Keyword(s):  
Raman Spectroscopy ◽  
Methanol Oxidation ◽  
Powder Diffraction ◽  
Temperature Programmed Reduction ◽  
X Ray ◽  
Temperature Programmed ◽  
Vanadia Catalysts

Preparation and Characterization of Ni-Modified Fe-Mo and Catalytic Selective Oxidation of p-Xylene

2012 ◽  
Vol 557-559 ◽  
pp. 1501-1504 ◽  
Author(s):  
Zu Zeng Qin ◽  
Zi Li Liu ◽  
Yan Bin Liu ◽  
Rui Wen Liu
Keyword(s):  
Photoelectron Spectrum ◽  
Sol Gel ◽  
Catalytic Performance ◽  
Ni Catalyst ◽  
Temperature Programmed Reduction ◽  
X Ray ◽  
Mo Catalyst ◽  
Ft Ir ◽  
Temperature Programmed

The preparation of the Fe-Mo-Ni catalyst using the sol-gel method was investigated. In addition, the catalytic selective oxidations of p-xylene (PX) to terephthalaldehyde (TPAL) on the Fe-Mo-Ni catalyst were also investigated. The catalysts were characterized using thermal analysis, H2-temperature programmed reduction (H2-TPR), Fourier transform infrared spectra (FT-IR), and X-ray photoelectron spectrum (XPS). The additional of Ni improves the catalytic activity of the Fe-Mo catalyst on selective oxidations of PX to TPAL. The optimal additive amount of Ni is 5%. XPS analysis shows that the introduction of Ni changes the internal structure of the Fe-Mo catalyst improves catalytic performance.

Study of Preparation, Characterization and Temperature-Programmed Reduction of NiO-ZnO Binary Materials

2013 ◽  
Vol 664 ◽  
pp. 515-520
Author(s):  
Chih Wei Tang ◽  
Jiunn Jer Hwang ◽  
Shie Hsiung Lin ◽  
Chin Chun Chung
Keyword(s):  
Weight Percent ◽  
Precipitation Method ◽  
Temperature Programmed Reduction ◽  
X Ray Diffraction ◽  
X Ray ◽  
Surface Areas ◽  
Temperature Programmed ◽  
Co Precipitation ◽  
Adsorption Desorption

The NiO-ZnO binary materials had been prepared by co-precipitation method. The weight percent of nickel of NiO-ZnO materials were 5, 10 and 20; they were pretreated under air at temperature of 300, 500 and 700°C, respectively. The characterization of NiO-ZnO materials were the thermal gravity analysis(TGA), X-ray diffraction(XRD), N2 adsorption-desorption at 77K, scaning electron microscope(SEM) and temperature-programmed reduction(TPR). The results revealed that surface areas of NiO-ZnO materials order from large to small were 20NiZn(OH)x(66 m2·g-1) > 10NiZn(OH)x(34 m2·g-1) > 5NiZn(OH)x(9 m2·g-1) after being calcined at the temperature of 500°C. Further, NiO-ZnO materials had two main reductive peaks at 390-415°C and 560-657°C, respectively. In all NiO-ZnO materials, 20NiZn(OH)x-C500 material had the highest surface area and the best interaction between NiO and ZnO.

Reduction Behaviour of WO3 to W under Carbon Monoxide Atmosphere

2016 ◽  
Vol 840 ◽  
pp. 305-308
Author(s):  
Fairous Salleh ◽  
Tengku Shafazila Tengku Saharuddin ◽  
Alinda Samsuri ◽  
Rizafizah Othaman ◽  
Mohamed Wahab Mohamed Hisham ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
Temperature Programmed Reduction ◽  
X Ray Diffraction ◽  
Reduction Behavior ◽  
X Ray ◽  
Isothermal Reduction ◽  
Reduction Behaviour ◽  
Temperature Programmed ◽  
Metal Phases

The reduction behaviour of tungsten oxide has been studied by using temperature programmed reduction (TPR) and X-ray diffraction (XRD). The reduction behavior were examine by nonisothermal reduction up to 900 oC then continued with isothermal reduction at 900 oC for 45 min time under (40% v/v) carbon monoxide in nitrogen (CO in N2) atmosphere. The TPR signal clearly shows one peak attributed to formation of suboxide W18O49 (more) and WO2 (less) observed at 80 min. The reduction product was investigated by varying the holding reaction time. Based on the characterization of the reduction products by using XRD, it was found that, nonisothermal reduction of WO3 at temperature 900 oC partially converted to some W18O49 and WO2 phases. However, after increased the reaction holding time for 45 min, WO3 phases disappeared and converted to WO2 and W metal phases. It is obviously shows that by hold the reduction time could improve the reducibility of the sample oxide. Furthermore, it is suggested that reduction by using CO as reducing agent follows the consecutives steps WO3 → WO2.92 → W18O49 → WO2 → W.

A combined use of optical microscopy, X-ray powder diffraction and micro-Raman spectroscopy for the characterization of ancient ceramic from Ebla (Syria)

2014 ◽  
Vol 40 (10) ◽  
pp. 16409-16419 ◽  
Author(s):  
Paolo Ballirano ◽  
Caterina De Vito ◽  
Laura Medeghini ◽  
Silvano Mignardi ◽  
Vincenzo Ferrini ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Optical Microscopy ◽  
Powder Diffraction ◽  
X Ray ◽  
Micro Raman Spectroscopy ◽  
Combined Use ◽  
Ancient Ceramic

scholarly journals Raman Spectroscopy for Characterization of Hydrotalcite-like Materials Used in Catalytic Reactions

2021 ◽  
Author(s):  
Luciano Honorato Chagas ◽  
Sandra Shirley Ximeno Chiaro ◽  
Alexandre Amaral Leitão ◽  
Renata Diniz
Keyword(s):  
Raman Spectroscopy ◽  
Density Functional ◽  
Mixed Oxides ◽  
Structural Characteristics ◽  
Catalytic Reactions ◽  
X Ray Diffraction ◽  
X Ray ◽  
Temperature Programmed ◽  
Materials Used

This chapter covers a brief review of the definition, structural characteristics and main applications of hydrotalcite, an interesting multifunctional material which finds applicability in different areas. Particularly, some catalytic reactions using hydrotalcite or mixed oxides derived from these materials are addressed (Ethanol Steam Reforming, Photochemical conversions, Hydrodesulfurization). The use of Raman Spectroscopy associated with other techniques, such as powder X-ray diffraction (XRD), Extended X-ray Absorption Fine-Structure (EXAFS), Temperature Programmed Reduction of hydrogen (H2-TPR), Fourier-Transform Infrared (FTIR) and Density Functional Theory (DFT) simulations, to characterize this type of material is addressed through examples described in the current literature. In this sense, multidisciplinary efforts must be made in order to increase the understanding of the properties of these materials and the catalytic behavior in the most varied reactions.

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