Porous silica materials derived from cage-siloxane: structural confinement and stabilisation of dispersed Au(0) nanoparticles

Abstract

Highly dispersed gold(Au) species exhibit unique catalytic properties that differ considerably from those of bulk Au or larger particles. However, achieving such dispersion while preserving their intrinsic characteristics remains a challenge. This difficulty often arises because conventional methods can alter the characteristics of the Au itself. This study addresses this issue using silica, a support material known for its weak interaction with active metal species. Specifically, we developed a novel nanoporous silica support functionalised with hydrosilyl groups using a cage-siloxane as a building block. These groups enable on-site reduction of Au³⁺ ions, allowing highly dispersed Au loading without introducing strongly interacting ligands. Importantly, the dispersion was retained even after calcination, indicating a confinement effect within the porous structure. This approach offers a promising strategy for stabilising Au species on inert supports, potentially advancing the design of robust and efficient Au-silica catalysts for heterogeneous catalysis.