Stability of boron-doped mesoporous SiC with high surface area in water-saturated air at 800 ​°C for diesel exhaust catalysis

SiC oxidizes and is structurally unstable at temperatures above 1000 ​°C in a water-containing oxidative gaseous environment. Herein, we explore the hydrothermal stability of high-surface-area mesoporous SiC (m-SiC) prepared using Pluronic F-127 as structure directing agent, with and without boron doping as synthesized by a magnesiothermic reduction method (700 ​°C for 12 ​h). Under hydrothermal treatment at 800 ​°C in a water-saturated air stream, the undoped m-SiC is completely oxidized and reduced to amorphous SiO2. Lightly doped boron-substituted m-SiC (m-BxSiC, B/Si ​= ​0.04) is significantly more stable and retains the structural characteristics of m-SiC. m-BxSiC shows significant (300 ​°C) catalytic performance (CO conversion, HC conversion, and NO oxidation), better Pt dispersibility, and retention of a smaller Pt particle size. Studies of hierarchically porous m-BxSiC/PS prepared with F-127 and polystyrene dual templating further confirmed the enhancement by boron doping of the 800 ​°C hydrothermal stability and the 300 ​°C catalytic activity. Mesoporous boron-doped Pt/SiC catalysts. [Display omitted] •Boron-doped mesoporous-SiC with high surface area was prepared by magnesiothermic reduction.•m-BxSiC exhibited substantially improved hydrothermal stability compared to undoped m-SiC.•Pt nanoparticle impregnated m-BxSiC showed enhanced nanoparticle dispersion.