(166d) Impact of Pore Size on Catalytic Behavior in Mesoporous Au@SiO2 Core-Shell Nanoparticles
AIChE Annual Meeting
Thursday, November 19, 2020 - 8:00am to 9:00am
The pore size of CSNPs was controlled via additional calcination and etching in a weakly alkaline environment. Under these conditions, investigation using TEM revealed the etching process to have minimal impact on gold core diameter. GC-FID analysis revealed both lower activity and benzaldehyde selectivity on CSNPs with higher pore sizes, suggesting the mesopores inhibit both the formation of large, undesired products and competitive adsorption of reactant phenyl groups, which block reactions on the surface.
The pore length of CSNPs was controlled via a series of sequential silica condensations around the gold core, increasing the thickness of the encapsulating silica shell. Investigation using TEM revealed higher shell growth using multiple additions of silica precursor compared to a single addition of equivalent mass. Benzyl alcohol oxidation using CSNPs with higher silica shell thickness demonstrated lower catalytic activity as shell thickness increases. An activation energy study revealed the Thiele modulus transitions from purely rate limited to the transition region over shell thicknesses studied.