Ordered mesoporous silica cubic particles decorated with silver nanoparticles: a highly active and recyclable heterogeneous catalyst for the reduction of 4-nitrophenol

Abstract

In this work, using a modified Stöber process, we synthesized ordered mesoporous silica cubic particles (OMS-C) and prepared a nanocatalyst (Ag–OMS-C) based on OMS-C with a high surface area via an in situ auto-reduction strategy. The as-prepared Ag–OMS-C nanocomposites demonstrated open mesopores (3.51 nm), a large specific surface area (540 m² g⁻¹) and a high pore volume (0.88 cm³ g⁻¹). The catalytic reduction of 4-nitrophenol (4-NP) over the Ag–OMS-C nanocatalyst was almost complete within 150 s without stirring and the rate constant k (30 × 10⁻³ s⁻¹) is much higher than those of other substrate-supported Ag nanocatalysts. Moreover, the Ag–OMS-C nanocomposites hold a stable catalytic efficiency over five reaction cycles. The results indicate that the Ag–OMS-C nanocatalyst exhibited high catalytic activity and good reusability toward the reduction of 4-NP, which might be attributed to the large specific surface area, the pore structure of the nanocatalyst, as well as the synergistic effect between OMS-C and AgNPs.