Beneficial Effect of W Incorporation in Supported Mo‐based Catalysts for the HDO of m‐Cresol

Abstract

The hydrodeoxygenation (HDO) of m‐cresol was investigated at 340 °C under 30 bar as total pressure over molybdenum oxide‐based catalysts. 10 wt.% Mo were first deposited on various supports (ZrO2, TiO2, Al2O3 and COK12). The use of oxophilic ZrO2 and TiO2 supports allowed to obtain the highest HDO catalytic performances. This result could be in link with the reducibility of Mo, which was found to be dependent on the support nature. Several catalysts containing both W and Mo in oxide phase supported on ZrO2 were then prepared using various heteropolyacids as precursors (H4SiMoxW12‐xO40 with x=0, 3, 6, 9 and 12). A synergy was observed between Mo and W and the best catalytic performance was obtained for SiMo9W3/ZrO2. More importantly, the presence of W improved the reducibility of Mo6+ to Mo5+ species, which quantity was correlated to catalytic activity suggesting that Mo5+ could be the active phase in HDO.

Transformation of Furfural-Acetone Condensation Adduct over Mo/SBA-15 Catalysts under Atmospheric Pressure

“…Partially reduced MoO3 will promote the adsorption of the oxygen-containing functional group on the vacancy site following the C-O bond cleavage by hydrogenolysis, and then further regeneration of the vacancy with H2. The synergism effect of MoOx with oxophilic species such as Zr 4+ can also enhance the HDO activity of Mo-based catalysts, as recently demonstrated by Farah et al [36].…”

“…Partially reduced MoO 3 will promote the adsorption of the oxygen-containing functional group on the vacancy site following the C-O bond cleavage by hydrogenolysis, and then further regeneration of the vacancy with H 2 . The synergism effect of MoO x with oxophilic species such as Zr 4+ can also enhance the HDO activity of Mo-based catalysts, as recently demonstrated by Farah et al [36]. In order to determine the presence of adsorbed organic compounds and/or coke deposits, the TG analysis coupled with a mass spectrometer was performed over the spent catalysts (Figure 6).…”

Interaction of Anisole on Alumina-Supported Ni and Mo Oxide Hydrodeoxygenation Catalysts

“…The NiO x catalyst does not contain pure NiO but possibly NiOOH and Ni–O–Al species, which could not be excluded from the Raman data. After heating in hydrogen, the APXPS data show that Mo 5+ and Mo 4+ are present for both Mo-containing catalysts, but the Mo 5+ oxidation state is largely agreed to be active for the HDO of phenolics. – While there are some studies that have focused on the activity of the Ni 2+ oxidation state, Ni 0 is the more researched and active catalyst.…”

Hydrogen Tunneling Exhibiting Unexpectedly Small Primary Kinetic Isotope Effects

“…[1] Hence, QMT manifestations are important in fields like enzymatic and conventional catalytic CÀ H bond activation. [11][12][13][14][15][16] Primary kinetic isotope effects (KIEs, e. g., k H /k D ) are commonly measured to probe QMT in chemical reactions. The semi-classical interpretation (from the Eyring's formulation of transition state theory (TST); others might prefer calling it quasiclassical [17] ) of primary H/D KIEs sets an upper limit of 7-10 for one-step hydrogen transfer reactions occurring at room temperature (corresponding to the maximum zero-point vibra-tional energy (ZPVE) difference).…”