1. Direct Stepwise Oxidation of Methane to Methanol over Cu–SiO2
- Author
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Selmi Erim Bozbag, Petr Šot, Jeroen A. van Bokhoven, Marco Ranocchiari, Maarten Nachtegaal, Carl Mesters, Bozbağ, Selmi Erim, Sot, Petr, Nachtegaal, Maarten, Ranocchiari, Marco, Van Bolchoven, Jeroen A., Mesters, Carl, Graduate School of Sciences and Engineering, and Department of Chemical and Biological Engineering
- Subjects
X-ray absorption spectroscopy ,010405 organic chemistry ,chemistry.chemical_element ,General Chemistry ,Partial pressure ,010402 general chemistry ,01 natural sciences ,Copper ,Catalysis ,Methane ,0104 chemical sciences ,Chemistry ,chemistry.chemical_compound ,Methane to methanol ,Silica ,Activation temperature ,XRD ,XAS ,chemistry ,Yield (chemistry) ,Methanol ,Zeolite ,Nuclear chemistry - Abstract
Cu supported on SiO2 can be used to directly convert methane to methanol in a stepwise process with no intrinsic need for a zeolite support. Effects of parameters such as the O-2 activation temperature, activation time, CH4 reaction temperature, CH4 partial pressure (pCH(4)), and Cu wt % on methanol yield were investigated. Increasing the O-2 activation temperature in the 200-800 degrees C range significantly improved the methanol yield, and when carried out at 800 degrees C, a methanol yield of 11.5 mu mol/g(ctalyst) was obtained after reaction with methane at 200 degrees C for the sample with 2 wt % Cu. Yield per mole of Cu increased exponentially from 1.0 to 59.1 mmol with decreased Cu wt % from 30 to 1, respectively. The increase in the O-2 activation time also strongly influenced the yield which corresponded to the increase in yield by a factor of >2 between 1 and 8 h. Increasing PCH4 from 0.05 to 1 atm resulted in a 5-fold increase in yield after activation at 450 degrees C; however, it resulted in at least 20% lower yields after activation at 800 degrees C showing that active sites of different nature were formed at different activation temperatures. The increase in yield with ramped O-2 activation temperature correlated with the dehydration of the samples as evidenced by X-ray absorption near-edge spectroscopy (XANES) and via mass spectroscopy (MS) traces of H2O during the O-2 activation step., Turkish Scientific and Technological Research Council (Scientific and Technological Research Council of Turkey (TÜBİTAK))
- Published
- 2018