Catalytic performance of AuIII supported on SiO2 modified activated carbon

Abstract

Silica was deposited onto activated carbon through TEOS hydrolysis and this composite was used as a support for the Au catalyst in acetylene hydrochlorination. Silica content and the catalyst synthesis process were both optimized. It was found that 1Au/5SiO₂/AC showed improved stability, while being as active as 1Au/AC. Thermogravimetric analysis (TGA) quantitatively revealed the synchronism of TEOS hydrolysis and Au deposition, which was believed to be the linchpin in 1Au/5SiO₂/AC synthesis. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) demonstrated that amorphous silica dispersed on the carbon surface uniformly as spherical particles. Silica deposition brought down the surface area of the catalyst while leading to better distribution of gold nanoparticles. Higher gold distribution degree guaranteed the catalytic activity of 1Au/5SiO₂/AC despite surface area loss. A higher level of resistance to acetylene, excellent surface property stability and less carbonaceous deposition were determined as the origin of the improved stability of 1Au/5SiO₂/AC.