New insights into the size and support effects of γ-Al2O3 supported Au catalysts for HCHO oxidation at room temperature

Strong metal support interaction (SMSI) between Au nanoparticles (NPs) and a non-reducible γ-Al2O3 support was revealed to affect HCHO oxidation at room temperature. Catalyst characterization by HRTEM and 27Al NMR revealed that Au NPs were encapsulated by the γ-Al2O3 support and that pentacoordinate Al3+ on the γ-Al2O3 surface acted as anchoring sites for Au nanoparticles. The SMSI in Au/γ-Al2O3 not only enhanced the dispersion of the Au NPs but also stabilized the NPs during the reaction. As a result, Au/γ-Al2O3 with strong SMSI exhibited high initial activity and stability in HCHO oxidation at room temperature. These findings provide new insights into Au NP size and support effects in Au/γ-Al2O3 catalysts used for HCHO oxidation at room temperature.