Pd-Sn Alloy Catalysts for Direct Synthesis of Hydrogen Peroxide from H and O in a Microchannel Reactor.

Direct synthesis of hydrogen peroxide (DSHP) from H and O offers a promising alternative to the present commercial anthraquinone method, but it still faces the challenges of low HO productivity, low stability of catalysts, and high risk of explosion. Herein, by loading in a microchannel reactor, the as-synthesized Pd-Sn alloy materials exhibit high catalytic activity for HO production, presenting a HO productivity of 3124 g kg h. The doped Sn atoms on the surface of Pd not only facilitate the release of HO but also effectively slow down the deactivation of catalysts. Theoretical calculations demonstrate that the Pd-Sn alloy surface has the property of antihydrogen poisoning, showing higher activity and stability than pure Pd catalysts. The deactivation mechanism of the catalyst was elucidated, and the online reactivation method was developed. In addition, we show that the long-life Pd-Sn alloy catalyst can be achieved by supplying an intermittent flow of hydrogen gas. This work provides guidance on how to prepare high performance and stable Pd-Sn alloy catalysts for the continuous and direct synthesis of HO.