Direct synthesis of hydrogen peroxide from H 2/O 2 and oxidation of thiophene over supported gold catalysts

Abstract

Direct synthesis of hydrogen peroxide from H 2 and O 2 was performed over supported gold catalysts. The catalysts were characterized by means of UV–vis, H 2-TPR, TEM and XPS. Based on the results we conclude that metallic Au is the active species in the direct synthesis of hydrogen peroxide from H 2 and O 2. During preparation process of catalyst by deposition–precipitation with urea, the pH value increased and the gold particle size decreased with increasing the urea concentration. The catalyst prepared with higher urea concentration showed a higher activity and its stability also was efficiently improved. Gold nanoparticles, supported on TiO 2 or Ti contained supports, gave a higher catalytic activity. Thiophene can be efficiently oxidized by hydrogen peroxide synthesized in situ from H 2 and O 2 over Au/TS-1.