Carboxylic acid Functionalized Cage-Type Mesoporous Silica FDU-12 as Support for Controlled Synthesis of Platinum Nanoparticles and Their Catalytic Applications

Abstract

Carboxylic acid functionalized 3D cage-type mesoporous silica FDU-12 with high surface area and pore volume was synthesized by a one-pot co-condensation method and used as support to synthesize Pt nanoparticles (NPs). The uniformly distributed COOH groups in the cage can control the growth of Pt NPs with high dispersion (Pt@CF-12). Pt@CF-12 was used as catalyst for the hydrolysis of ammonia borane to generate H₂ and for the reduction of 4-nitrophenol to 4-aminophenol. The catalyst exhibits higher catalytic activity (H₂ generation rate of 17.8 L ${}_{H{}_2}$ min^-1 $g_{\mathrm{cat}}^{-1}$ ) and lower activation energy of 30.67 kJ mol^-1 compared with other Pt-based silica catalysts due to the small size of the Pt NPs (3.5 nm) and cage-type porous structure of the support, which allowed easy diffusion of reactants. Pt@CF-12 has excellent durability, since the support prevented NP aggregation and leaching of NPs during catalysis. Pt@CF-12 can convert 93 % of 4-nitrophenol to 4-aminophenol within 10 min.

Keywords: heterogeneous catalysis; mesoporous materials; nanoparticles; platinum; supported catalysts.