Abstract: H₂O₂ synthesis directly from H₂ and O₂, as a "green process" and "atomic-economic reaction", is one of the most promising processes for replacing anthraquinone autoxidation process. In this paper, Pd/HAp (hydroxylapatite) catalyst was prepared by the conventional incipient-wetness impregnation method and highly dispersed Pd particles with an average size of 2.5 nm were obtained. Kinetic studies of H₂O₂ hydrogenation and direct synthesis of H₂O₂ were performed over a Pd/HAp catalyst and apparent activation energies and reaction orders with respect to H₂ and O₂ were calculated by power law functional models. Kinetic parameters indicated that the formation of H₂O₂ was favored at a lower reaction temperatures and higher O₂ partial pressure, while higher H₂ partial pressure would facilitate H₂O formation.

Key words: synthesis, hydroxylapatite, catalyst, kinetics

摘要： H₂和O₂直接合成H₂O₂过程绿色环保，反应具有原子经济性，是最有潜力的H₂O₂合成新方法之一。采用等量浸渍法，将Pd负载于羟基磷灰石（HAp）载体上，得到了高分散的Pd/HAp纳米催化剂，Pd平均粒径2.5 nm。运用幂指数模型，研究该催化剂在H₂O₂加氢及H₂和O₂直接合成反应中的动力学，计算得到H₂O₂加氢、H₂O₂和H₂O的生成反应的表观活化能及O₂、H₂表观反应级数。结果表明低温及高O₂分压有利于H₂O₂的生成，而高H₂分压则有利于H₂O的生成。

关键词: 合成, 羟基磷灰石, 催化剂, 动力学