Microreactor coating with Au/Al2O3 catalyst for gas-phase partial oxidation of ethanol: Physico-chemical characterization and evaluation of catalytic properties

A straightforward and reliable method was successfully developed for stainless steel microreactor coating. The importance of this coating method lies in using an already pre-prepared Au/Al2O3 catalyst without incorporation of any binders, addressing the importance of the interplay between the catalyst particle size and slurry viscosity in optimization of the uniformity, stability and thickness of the coating layers. The catalyst and the coated microplatelets were characterized thoroughly using nitrogen adsorption, X-ray Diffraction, Fourier Transform Infrared Spectroscopy, Scanning Electron Microscopy, confocal microscopy, laser diffraction, viscosity measurements, Transmission Electron Microscopy, Energy-dispersive X-ray, Inductively Coupled Plasma- Optical Emission Spectrometry and X-ray Photoelectron Spectroscopy. Moreover, stability of the coating layers was assessed in gas phase partial oxidation of ethanol. Initial increase in the catalyst activity with time on stream was likely due to changes in the gold oxidation state while minor catalyst deactivation could mainly be correlated with coking.