Glucose-Assisted Preparation of a Nickel–Molybdenum Carbide Bimetallic Catalyst for Chemoselective Hydrogenation of Nitroaromatics and Hydrodeoxygenation of <i>m</i>‑Cresol

Developing a safe, facile, clean, low-cost, and scalable new method to replace the conventional methane reductive carburization process for preparing carbon-nanotube, coverage-free, highly dispersed, metal carbide based bimetallic catalysts without a sacrificial metal loading is of great significance but remains a challenge. In this work, we develop a facile and robust strategy for successfully preparing a highly dispersed supported nickel–molybdenum carbide (NiMo₂C) bimetallic catalyst on mesoporous silica [NiMo₂C/SBA-15­(Glu.)], in which the renewable glucose is employed to serve as an assisting agent for high metal dispersion within the mesoporous channels of SBA-15 in the impregnation process and as a carbon source to replace flammable methane for metal carbide formation through a reductive carburization process. From diverse characterization results, the as-prepared NiMo₂C/SBA-15­(Glu.) catalyst demonstrates a much higher metal dispersion (ca. 4.1 nm in this work vs ca. 80 nm aggregates by the conventional method, as proven by transmission electron microscopy, X-ray diffraction, CO chemosorption, etc.) and promoted synergy effect between Ni and Mo₂C than the NiMo₂C/SBA-15­(Ref.) prepared by a conventional impregnation method, followed by methane reductive carburization (as proven by X-ray photoelectron spectroscopy and H₂ temperature-programmed reduction); besides, the growth of carbon nanotubes is eliminated. As a consequence, the NiMo₂C/SBA-15­(Glu.) catalyst shows unexpectedly 18 times higher catalytic specific activity for chemoselective hydrogenation of nitrobenzene and 12 times higher for the hydrodeoxygenation of <i>m</i>-cresol than conventional NiMo₂C/SBA-15­(Ref.). Moreover, NiMo₂C/SBA-15­(Glu.) shows a notably different product distribution for the hydrodeoxygenation of <i>m</i>-cresol owing to the bifunctional effect of Mo₂C. The as-prepared supported NiMo₂C catalyst can be extended to other transformations, and also the developed method in this work can be extended for the preparation of other metal carbide catalysts toward diverse applications