CO Methanation on Mesoporous Ni-VOx/FDU-12 Catalyst: Effects of the VOx Promoter on Low-Temperature Activity

Herein, a series of Ni-VOx/FDU-12 catalysts are prepared by an incipient impregnation method with FDU-12 (cubic, Fm-3m) as the support. The samples are characterized by nitrogen adsorption, X-ray diffraction, scanning electron microscopy, transmission electron microscopy, H-2-temperature programmed reduction, and X-ray photoelectron spectroscopy. Among all catalysts, Ni-VOx/FDU-12 with NiO of 10 wt% and V2O5 of 2 wt% (10N2VF) show the best catalytic performance, which reaches maximum CO conversion and CH4 yield of 99.4% and 89%, respectively, at 325 degrees C. The lifetime test is conducted at a constant temperature of 450 degrees C for 100 h at 0.1 MPa and a high weight hourly space velocity (WHSV) of 60 000 mL g(-1) h(-1). The 10N2VF exhibit high antisintering and coking properties. The addition of the vanadium promoter improve Ni dispersion and change Ni electron density, which enhance the low-temperature ability for CO dissociation via the weakening of C-O linkage. In contrast, a large number of oxygen vacancies formed by the oxidation-reduction cycle of V5+/V4+/V3+ can enhance the dissociation of the by-product CO2 and generate oxygen intermediates, which prevent carbon deposition on the surface of Ni particles.