Palladium-Incorporated α-MoC Mesoporous Composites for Enhanced Direct Hydrodeoxygenation of Anisole

Abstract

Hydrodeoxygenation (HDO) is one of the promising catalytic routes for converting biomass derived molecules to high value products. A key step of HDO is the cleavage of an aromatic C–O bond to accomplish the deoxygenation step, however, which is energetically unfavorable. Herein, we report a series of palladium (Pd)-incorporated α-phase of molybdenum carbide (α-MoC) mesoporous composites for enhanced HDO activity of a biomass model molecule, anisole. The catalysts, x%Pd/α-MoC (x% is the molar ratio of Pd/Mo), were investigated by X-ray diffraction (XRD), temperature programmed reduction (TPR), temperature programmed desorption (TPD), Brunauer–Emmett–Teller (BET), Raman, transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS) techniques. Pd is highly dispersed on α-MoC when x% ≤ 1%, but aggregate to form nanoparticles when x% = 5%. The x%Pd/α-MoC catalysts (x% ≤ 1%) show enhanced HDO activity in terms of turnover frequency (TOF) and apparent activation energy barrier (Ea) compared with α-MoC and β-Mo2C catalysts. The TOF of 1%Pd/α-MoC catalyst at 160 °C is 0.115 h−1 and the Ea is 48.2 kJ/mol. Moreover, the direct cleavage of aromatic C–O bond is preferred on 1%Pd/α-MoC catalyst. The enhanced HDO activity is attributed to superior H2 dissociation ability by the highly dispersed Pd sites on carbide. This work brings new insights for rational design of the catalyst for selective C–O bond activation.

Carbonization of a Molybdenum Substrate Surface and Nanoparticles by a One-Step Method of Femtosecond Laser Ablation in a Hexane Solution

“…These three weak peaks should have originated from Mo−C modes, revealing the formation of MoC. 73 The NP deposition was removed from the substrate by using a spatula and collected in a glass sampling bottle with ethanol. The NPs were then dispersed in an ethanol solution using the agitation induced using an ultrasonic cleaning machine.…”

“…Very weak peaks located at around 660, 820, and 995 cm –1 were observed for the Raman spectra of the laser-ablated area and NP deposition, which can be attributed to the characteristic peaks of MoO 3 or Mo 2 C. − However, these three peaks were not observed for the Mo substrate, suggesting that the surface molybdenum oxide contaminations are not detectable in the Raman measurement. These three weak peaks should have originated from Mo–C modes, revealing the formation of MoC …”

Performance of Anisole and Isobutanol as Gasoline Bio-Blendstocks for Spark Ignition Engines

“…Nevertheless, anisole, due to its molecular structure, can represent phenolic groups commonly found in pyrolysis oil [72] and is frequently used as a bio-oil surrogate [73,74]. Anisole can be considered a direct gasoline bio-blendstock [39,42,43] or a precursor for further upgrading to gasoline-like products [26,[75][76][77][78].…”

Low-Temperature Hydrogenation of Toluene Using an Iron-Promoted Molybdenum Carbide Catalyst

“…Meanwhile, iterative catalytic hydrogenation/dehydrogenation of arenes/corresponding naphthalene pairs has been used for hydrogen storage and transportation [3]. To convert stable molecules under mild conditions (for example, below 100 • C) with high selectivity and yield, noble metals such as platinum, ruthenium and rhodium are required as the main catalytic components in these processes [4][5][6][7][8][9][10][11][12][13]. Nevertheless, these catalysts have not received widespread industrial use because of their high cost, complex preparation procedures and vulnerability to sulfur poisoning [14][15][16][17].…”