Preparation of NO-doped β-MoO3 and its methanol oxidation property

• Published in: Materials chemistry and physics Vol. 184; pp. 5 - 11
• Main Authors: Pham, Thi Thuy Phuong, Nguyen, Phuc Hoang Duy, Vo, Tan Tai, Luu, Cam Loc, Nguyen, Huu Huy Phuc
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-12-2016
• Subjects: DTA; Oxidation; Oxides; Raman spectroscopy and scattering; XPS; DTA; Oxides; Raman spectroscopy and scattering; XPS; Oxidation
• ISSN: 0254-0584; 1879-3312
• DOI: 10.1016/j.matchemphys.2016.09.048

The major drawback of the industrial iron molybdate catalysts which is their deactivation problem has driven the study of alternative catalysts for formaldehyde production from methanol. In this paper, NO-doped β-MoO3 was successfully synthesized from the commercial molybdic acid powder (H2MoO4) and characterized by differential thermal analysis (DTA), X-ray Diffraction (XRD), Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). Results obtained from XRD and Raman spectroscopy indicated that the synthesized sample has all features of the well-known β-MoO3 except for the presence of a new small peak. The curve-fitting of XPS spectra revealed that nitrogen-containing species may be present in the form of negatively charged nitrogen oxide in the prepared sample. Due to its metastable nature, NO-doped β-MoO3 may be transformed into the thermally stable α-MoO3 at temperature higher than 400 °C as pointed out by DTA study. However, when the reaction temperature was as low as 300 °C, the catalyst was stable for partial methanol oxidation with no significant change in activity during 30 h of catalytic study. Methanol conversion and formaldehyde selectivity were maintained at about 98% and 99%, respectively.
•NO-doped β-MoO3 was synthesized by a facile and effective method.•Its structure was confirmed by XRD, Raman and XPS analysis.•XMeOH and SHCHO were stabilized at 98% and 99%, respectively, for the first 30 h.