CAREER: Molecular Understanding and Catalyst Design for the Direct Synthesis of H2O2

摘要(Flaherty；1553137)目前，在纸浆、造纸和日用化学品的制造中，每年都有数以百万计的有害氯化物被用于选择性氧化和漂白反应。过氧化氢(H_2O_2)是氯化化合物的“绿色”替代品，但没有得到广泛应用，因为目前的生产方法只有在非常大的规模下才在经济上可行。这项拟议的研究将研究另一种催化方法--从氢(H2)和氧(O2)气体直接合成过氧化氢--这将使现场生产过氧化氢用于规模较小、更常见的加工设施。建议的研究与以年轻女性为重点的教育项目相结合，重点是培养研究和研究指导技能。该研究将在系统的研究中结合催化动力学和现场光谱测量来确定：1)直接合成过氧化氢的机理，2)表面、溶剂和液态中间体在形成活性中间体中的作用，以及3)催化剂组成和溶剂性质对反应速度和选择性的综合影响。最初的工作将集中在钯(Pd)和钯-金(PdAu)簇合物作为活性催化材料，但从这些材料获得的知识将用于生成指导原则和活性描述符，以确定PdAu催化剂的廉价替代品。为了实现这些目标，将采用动力学和(非原位和原位)红外光谱技术相结合的方法来探索负载金属团簇的液-固界面上的催化化学。这项研究将涉及设计参数，如：金属团簇的大小和组成，亲电吸附剂的作用，以及溶剂性质，如pH和极性。尽管这些研究专门针对过氧化氢的直接合成，但这项工作将开发未来研究液-固界面上广泛的氧化和还原化学所需的工具和专业知识。

Abstract (Flaherty; 1553137)Currently millions of tons of hazardous chlorinated compounds are used for selective oxidation and bleaching reactions in the manufacture of pulp, paper, and commodity chemicals each year. Hydrogen peroxide (H2O2) represents a "green" alternative to chlorinated compounds, but it is not widely used because the current production method is economically viable only at very large scales. The proposed study will investigate an alternative catalytic approach - direct synthesis of H2O2 from hydrogen (H2) and oxygen (O2) gases - that would enable H2O2 production on-site for use in smaller, more common processing facilities. The proposed research is integrated with educational programs focusing on young women with emphasis on building research and research-mentoring skills.The research will combine catalytic kinetic and in situ spectroscopic measurements in a systematic investigation to determine: 1) the mechanism for direct synthesis of H2O2, 2) the roles of surfaces, solvents, and liquid-phase intermediates in forming reactive intermediates, and 3) the combined effects of catalyst composition and solvent properties on reaction rates and selectivities. The initial work will focus on palladium (Pd) and palladium-gold (PdAu) clusters as the active catalytic materials, but learning derived from those materials will be used to generate guiding principles and activity descriptors to identify inexpensive alternatives to PdAu catalysts. To achieve these goals, a combination of kinetic and (ex situ and in situ) infrared spectroscopic techniques will be employed to probe the catalytic chemistry at the liquid-solid interfaces of supported metal clusters. This investigation will involve design parameters such as: size and composition of the metal clusters, the role of electrophilic adsorbates, and solvent properties such as pH and polarity. Although these studies specifically target the direct synthesis of H2O2, the work will develop tools and expertise needed for future investigations of a broad range of oxidative and reductive chemistries at liquid-solid interfaces.