Boosting Toluene Selectivity over Mo-Modified Ni@Silicalite-1 Catalysts in Hydrogenolysis of Vapor-Phase <i>m</i>-Cresol

The hydrogenolysis of biobased phenolics into high-value arenes is considered as the potential alternative strategy to petroleum-based arenes, but the widely used Ni-based catalysts generally suffer from a poor arenes yield. Herein, we demonstrated a strategy by introducing Mo species into Ni@Silicalite-1 (Ni@S-1) to drive the diffusion of Ni particles embedded at the external surface layer of S-1 into its deeper internal crystals to form uniformly confined NiMo bimetallic nanoparticles (2–5 nm) with rich oxygen vacancies. As for hydroxyl hydrogenolysis of vapor-phase m-cresol as an example, NiMo@S-1 presented a remarkable toluene production rate of 480.3 μmol[toluene]·g[Ni]–1·s–1 with a hydroxyl hydrogenolysis rate of 501.9 μmol[m-cresol]·g[Ni]–1·s–1 at 350 °C under reported minimal metal Ni loading, suggesting the achievement of the highest hydroxyl hydrogenolysis rate over disclosed Ni-based catalysts by far. As analyzed, such induced confined structures enforce the m-cresol adsorbed onto the metal surface via the vertical geometry for the shape-selective effect of zeolites, and the oxygenophilic oxygen vacancies of NiMo@Silicalite-1 further strengthen the vertically oriented m-cresol to interact with active sites through the hydroxyl group rather than the phenyl group, thus greatly enhancing the desired hydroxyl hydrogenolysis process.