Ultrasmall Particle Sizes of Walnut-Like Mesoporous Silica Nanospheres with Unique Large Pores and Tunable Acidity for Hydrogenating Reaction

Abstract

The large particle sizes, inert frameworks, and small pore sizes of mesoporous silica nanoparticles greatly restrict their application in the acidic catalysis. The research reports a simple and versatile approach to synthesize walnut-like mesoporous silica nanospheres (WMSNs) with large tunable pores and small particle sizes by assembling with Beta seeds. The as-synthesized Beta-WMSNs composite materials possess ultrasmall particulate sizes (70 nm), large radial mesopores (≈30 nm), and excellent acidities (221.6 mmol g^-1 ). Ni₂ P active phase is supported on the surface of Beta-WMSNs composite materials, and it is found that the obtained composite spherical materials can reduce the Ni₂ P particle sizes from 8.4 to 4.8 nm with the increasing amount of Beta seeds, which can provide high accessibilities of reactants to the active sites. Furthermore, the unique large pores and ultrasmall particle sizes of Beta-WMSNs samples facilitate the reduction of the diffusion resistance of reactants due to the short transporting length, thus the corresponding Ni₂ P/Beta-WMSNs composite catalysts show the excellent hydrogenating activity compared to the pure Ni₂ P/WMSNs catalyst.

Keywords: beta; hydrogenating reaction; mesoporous silica nanospheres.