Silica-Decoration Boosts Ni Catalysis for (De)hydrogenation: Step-Abundant Nanostructures Stabilized by Silica

摘要

Ni nanoparticles supported on SiO2 were decorated with additional SiOx species by impregnation with tetraethoxysilane (Si(OEt)(4)). The combination of electron microscopy, infrared analysis, and density functional theory (DFT) calculations revealed that the SiOx-decoration made the surface morphology of Ni nanoparticles highly rough and step-abundant due to the significant stabilization of low-coordination-number sites. The SiOx-decorated Ni exhibited 50 times higher catalytic activity for the dehydrogenation of methylcyclohexane to toluene than pure Ni. DFT calculations revealed that the Ni(211) step sites had a more favorable C-H activation than Ni(111) terrace sites and well reproduced the experimental apparent activation energies.