Solvent-free and rapid synthesis of mesoporous Pt–iron oxide catalysts via mechanochemical assembly

Abstract

Mesoporous Fe_xO_y and Pt@Fe_xO_y have demonstrated promising performance in catalysis. However, current methods usually use wet chemistry, which poses several drawbacks. In this study, we introduce a simple process of mechanochemical assembly between an iron salt and a triblock copolymer in the solid state that can not only directly form abundant mesopores into Fe_xO_y, but also enable a high dispersion of Pt species at the nm or sub-nm scale. In this regard, mesoporous Fe_xO_y and Pt@Fe_xO_y catalysts with high surface areas (up to 149 m² g⁻¹) and narrow pore size distributions (∼5 nm) can be obtained in a solvent-free and rapid (0.5 h) way. The kinetic energy and frictional heating of ball milling are expected to promote the interaction and diffusion between iron precursors and surfactants, while the solvent-free feature confines their assembly to the mesophase of the P123 copolymer. Moreover, these Pt@Fe_xO_y catalysts provide good activity in the total oxidation of propylene and CO.