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RSC Advances
Page 5 of 6
DOI: 10.1039/C6RA23474G
RSC Advances
ARTICLE
The nature of the catalyst after 2000 hours’ test was then
recorded by XRD and STEM. Figure 9a showed the compared XRD
chemisorbed O2 atoms was measured by a hydrogen pulse chromatographic
technique on a Micromeritics Autochem II 2920 equipped with a TCD.
curves on fresh H2-reduced and reacted CuNi(2)/SiO2 catalyst. Two Hydrogen pulse-dosing was repeated until there has no change. The
consumed amount of hydrogen was the value obtained by subtracting the
small area of the first few pulses from the area of the other pulses. Copper
loading of all reduced catalysts was analyzed by X-ray fluorescence (XRF)
on a Bruker S4 Pioneer. Copper dispersion was calculated by dividing the
amount of chemisorption sites into total supported copper atoms. X-ray
photoelectron spectroscopy (XPS) studies were performed on a Kratos AXIS Ultra
DLD spectrometer equipped with a high temperature gas reaction cell. All the
spectra were well collected with monochromatic Al Kα The C 1s peak at 284.8 eV
was set as reference for binding energy calibration. All the spectrum processing
and peak fitting were performed with CasaXPS.
samples have full same featured peaks, meaning the reacted one
keeping original structure unchanged. Shaper peak implies the
particle size of reacted one is a little larger than fresh one. With
Scherrer Formula, the particle size of reacted one could be calculated
to 26.5 nm. Figure 9b showed the STEM image. The average particles’
size was around 25 nm and separated obviously. Both the results
revealed the catalyst’s activites be able to hold its particle size and
dispersibility, and corresponding its super stability.
All the reactions were carried out in a continuous flow, fixed-bed reactor
and 5g catalysts were packed in the reactor. Prior to the reaction, the catalyst
o
was reduced at 260 C in H2 flow. DMO and H2 were fed into the reactor
Conclusions
In conclusion, Cu-based model catalysts by adding nickel to
improve performance have been explored for the reaction of DMO to
EG. The appropriate amount of nickel could be vital for the
optimized catalysis. The Ni-O species can effectively stabilize Cu
and is ideal for using in industry as its over 99% conversion, 95%
selectivity, and over 2000 hours’ stability. The strategy for the
synthesis of stable mixed oxides provides a simple method in
catalyst preparation and selectivity control. Results from the current
study demonstrate the high potential to synthesize mixed metal
oxides catalysts for practical applications.
using an injection pump, and the LHSV flow rate of DMO was 0.55 h-1. The
reaction temperature was adjusted between 210oC and 230oC. The reaction
pressure was maintained at 3.0 MPa. The molar ratio of H2 to DMO was set
as 100 (mol/mol). The hydrogenation products were analyzed using gas
chromatography (Agilent 7890) equipped with a flame ionization detector
and a capillary column (DB-200). The main products and byproducts were
identified by GC-MS method on Agilent 5975C inert XL EI/CI MSD.
Acknowledgements
The authors thank the partially financial support from the SINOPEC,
National Natural Science Foundation of China (NSFC 21373272 and
2013CB93410).
Experimental
The Cu-based catalysts were prepared by a co-precipitation method in
which 0.20M aqueous solution of Cu(NO3)2.3H2O, Ni(NO3)2.3H2O and
proper amount of silica sol were taken and precipitated using 0.2M aqueous
sodium carbonate at ambient temperature. The precipitate was aged further
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