Effect of carburising agent on the preparation of molybdenum carbides by plasma and their catalytic HDO of o-cresol

Abstract In this paper, molybdenum carbides have been prepared by DBD plasma using mixtures of H 2 and CH 4 . C 2 H 4 or C 3 H 8 with different hydrocarbon/H 2 successfully, and characterized by XRD, XPS, Raman, CO 2 -TPO and H 2 -TPD. The results of XRD show that the different carburising agents and C/H 2 have little influence on β-Mo 2 C particles size at input power 40 W. Carburising with a mixture of H 2 and C 2 H 4 gives rise to ƞ-MoO 1 − x and then deeply carbonized to β-Mo 2 C, while when using CH 4 or C 3 H 8 as the carbon source, MoO 2 is directly carbonized to β-Mo 2 C. Besides, the kind of carburising agents has no effect on the input power of synthetic β-Mo 2 C (40 W). XPS, Raman and CO 2 -TPO characterization revealed the effect of carburising agents and hydrocarbon /H 2 on the amount of carbon deposition during the surface of the β-Mo 2 C. Under the same C/H 2 , the surface of Mo 2 C-E has the lowest carbon deposition, while the carbon deposition on the surface of Mo 2 C-M is highest, and with the increasing of hydrocarbon /H 2 of the same carburising agent, the carbon deposition on the surface increases. Mo 2 C-M, Mo 2 C-E and Mo 2 C-P were evaluated in the hydrodeoxygenation of o-cresol, using a stainless-steel tubular reactor. The results showed that the Mo 2 C-E (C 2 H 4 /H 2 = 1/8) shows the better catalytic performance and the toluene yield is over 80%, which can be attributed to the more active sites and the lower carbon deposition, and this result is consistent with the result of H 2 -TPD.