Insight into Au/ZnO catalyzed aerobic benzyl alcohol oxidation by modulation–excitation attenuated total reflection IR spectroscopy

Abstract

The catalytically active sites of supported gold nanoparticles play a crucial role in the selective alcohol oxidation reactions. In this study, we designed and developed a new strategy to prepare Au/ZnO catalysts, possessing similar Au particle sizes of 2–3 nm but different surface species (e.g., active oxygen species). The Au/ZnO catalysts, annealed at 300 °C and 350 °C in air, exhibit the highest concentration of the chemisorbed or dissociated oxygen species (O_C) and showed superior catalytic activity in the selective aerobic oxidation of benzyl alcohol to benzaldehyde. These catalytic results were further evidenced by the operando attenuated total reflection-infrared (ATR-IR) spectroscopy combined with modulation excitation spectroscopy (MES).