Facile preparation of highly active zirconia-supported gold nanoparticle catalyst

Abstract

Efficient production of hydrogen peroxide (H₂O₂) from oxygen (O₂) is an important research topic in chemistry. Au nanoparticles loaded on n-type semiconducting metal oxides by the deposition precipitation (DP) method (Au/n-MOs) are known to possess catalytic activity for two electron-oxygen reduction reaction. In this study, zirconia-supported Au nanoparticles (NPs) were prepared by the usual DP method (Au/ZrO₂-DP) and a modified DP method with a pre-step of long-term stirring of ZrO₂ NPs in HAuCl₄ solution (Au/ZrO₂-MDP). Regardless of the insulating character of ZrO₂, Au/ZrO₂-MDP stably yields H₂O₂ from O₂ and HCOOH at 25 °C with a turnover frequency (TOF) of 1.0 × 10² h⁻¹ and selectivity of 97%. The TOF is much larger than the values of Au/ZrO₂-DP and various Au/n-MOs. Spectroscopic measurements indicated that the unexpectedly high catalytic activity of Au/ZrO₂-MDP can be induced by effective introduction of O-vacancies to the ZrO₂ surface.