项目名称: 氧化铈表面活性氧物种的分子尺度调控
项目编号: No.21303195
项目类型: 青年科学基金项目
立项/批准年度: 2014
项目学科: 数理科学和化学
项目作者: 杨帆
作者单位: 中国科学院大连化学物理研究所
项目金额: 26万元
中文摘要: 开发高效的低温氧化催化剂是当前催化研究的一个重点,这其中氧化铈是极具潜力的催化氧化材料,室温下即可与O2反应,形成一系列的表面氧物种。由于氧化铈表面结构的复杂性,对于这些氧物种的形成机理,至今未能有完善的理解。我们拟结合STM,IRAS和EPR等表征技术来研究氧化铈模型表面,考察氧化铈表面不同种类的氧空位是否与不同氧物种的形成存在对应关系;通过对不同氧物种的形成过程的认识,理解氧空位与O2之间的电子转移机制。当然,体相氧化铈的活性,不足以在室温条件下产生十分活泼的氧物种,我们可以通过纳米和界面限域效应来进一步调变氧化铈的电子结构,以增强其与O2的作用。由于氧化物和金属界面的强相互作用,负载的氧化物纳米结构具有很好的可调控性。低价态的活性中心可以在界面处得到稳定,而氧化物本身也可形成一系列迥异于体相的新奇结构。我们预期可通过对界面限域氧化铈体系的精确调控,实现低温下活性氧化物种的选择性生成。
中文关键词: 活性氧物种;选择性氧化;界面限域;电子结构;纳米氧化物
英文摘要: Tailoring the generation of active oxygen species on oxide surfaces, especially under mild conditions, is center to current catalysis research, partially owing to its potential application in the green chemistry of chemical conversion, emission control during cold start, oxygen reduction in fuel cell and lithium-air batteries. Paralleling its great importance is the tremendous difficulties confronting the oxidation catalysis research, in identifying the active sites on a complex oxide surface and understanding their role in O2 activation. Taking ceria, a renowned material for catalytic oxidation, as an example, previous spectroscopic studies have identified a series of active oxygen species on ceria, upon its contact with O2 at room temperature. While surface oxygen vacancies on ceria are generally expected as the sites for O2 activation, where and how these different oxygen species are generated remain unknown. Recent advances in the microscopic studies of ceria surfaces revealed a few types of oxygen vacancies at the ceria surface, which leads to the hypothesis that the series of active oxygen species could be generated by these different oxygen vacancies, respectively.Surface science studies, combing STM, IRAS and EPR, on ceria model surfaces will thus allow the answer to this hypothesis.Certainly,the bulk ce
英文关键词: active oxygen species;selective oxidation;interface confinement;electronic structure;oxide nanostructures