Surface stabilization of gold by sol–gel post-modification of alumina support with silica for cyclohexane oxidation

Gold nanoparticles were stabilized on alumina support by silica via a surface sol–gel post-modification method and applied for the catalytic cyclohexane oxidation to cyclohexanone and cyclohexanol using oxygen in the absence of any solvent and initiator. The results show that the surface doping of alumina support with silica is highly effective in stabilizing gold nanoparticles subjected to calcination at 500 °C for 3 h. Moreover, the catalytic activity in terms of specific reaction rate and the selectivity to cyclohexanone are appreciably enhanced probably due to a decreased acidity and hydrophilicity by surface substitution of alumina with silica.