Insight into the role of PEG on Mo-Bi based catalyst in isobutene selective oxidation to methacrolein

• PEG-assisted hydrothermal synthesis can reduce the loss of Co and Cs elements. • The addition of PEG increases the CoMoO 4 content and inhibits the presence of MoO 3 . • Weaker acid strength and fewer acid sites are obtained over catalysts with PEG-assisted. • PEG-assisted catalysts improve the selectivity and yield of MAL from isobutene significantly. Mo-Bi based catalyst has been synthesized by PEG-assisted hydrothermal method, and tested in selective oxidation of isobutene to methacrolein (MAL). It is found that the catalysts assisted by PEG exhibited higher selectivity and yield of MAL in oxidation of isobutene. To investigate the role of PEG on Mo-Bi based catalyst, a series of MoBiFeCoCeCs mixed oxide catalysts were prepared by PEG-assisted hydrothermal method. By combining the characterization of Mo-Bi based catalyst obtained by using X-ray diffraction (XRD) patterns, N 2 physisorption measurements, Fourier transform infrared spectroscopy (FT-IR), NH 3 temperature-programmed desorption (NH 3 -TPD) measurements, X-ray photoelectron spectroscopy (XPS), X-ray fluorescence (XRF) spectroscopy and scanning electron microscope (SEM), it was verified that the assistance of PEG could change metal composition and states, inhibit agglomeration of particles and adjust acidity of catalyst. Our finding may suggest the relationship of selective oxidation of isobutene with Mo-Bi based catalysts.