Functional confinement of a zinc-oxide-supported gold catalyst enhances the direct synthesis of hydrogen peroxide

Due to the intensive energy consumption and environmental unfriendliness of the current industrial anthraquinone process for producing hydrogen peroxide, it is of interest to develop a clean and efficient alternative. Herein, we report that a zinc-oxide-supported gold catalyst encapsulated by a silica overlayer efficiently catalyzes the direct synthesis of hydrogen peroxide from carbon monoxide, oxygen, and water. Detailed characterizations demonstrate that the confinement effect of the silica overlayer may enhance hydrogen peroxide productivity by limiting the agglomeration of gold nanoparticles, inhibiting the hydrogen peroxide degradation activity, and improving the hydrophilicity of the catalyst surface. Isotope-labeling experiments and theoretical calculations reveal that both oxygen atoms in hydrogen peroxide come from molecular oxygen, and that a consecutive hydrogenation process is followed. This work poses a facile strategy to construct highly active catalysts for the direct synthesis of hydrogen peroxide, employing the confinement effects of an overlayer.