One-pot synthesis of ultrasmall MoO3 nanoparticles supported on SiO2, TiO2, and ZrO2 nanospheres: an efficient epoxidation catalyst

Abstract

Ultrasmall molybdenum oxide (MoO₃) nanoparticles supported on various (SiO₂, TiO₂ or ZrO₂) nanospheres were synthesized in one pot using a reverse micelle method. The prepared catalysts were thoroughly characterized by various physico-chemical methods. TEM images showed uniform dispersion of MoO₃ nanoparticles (1.5–4 nm) onto silica (∼275 nm). No separate MoO₃ particles were identified from TEM for MoO₃/TiO₂ (∼10.5 nm) and MoO₃/ZrO₂ (∼6.5 nm) because AHM reacted with titanium and zirconium hydroxides to form solid solution. Among the prepared catalysts MoO₃/SiO₂ showed excellent catalytic activity (up to 90% conversion and 100% epoxide selectivity) for olefin epoxidation. The catalyst was successfully recycled up to five cycles without losing much activity and selectivity.