双非贵金属催化剂/多孔铋基纳米片复合材料的构筑及光催化性质研究

Visible-light-responding Bi-based photocatalysts have attracted much attention. The difficulty and bottleneck of current study still remain to improve photocatalytic activities of the materials from the viewpoint of practical applications. The preparation of porous nanosheets can enhance the activities of Bi-based photocatalysts. However, the preparation of Bi-based porous nanosheets by a general route is still a challenging task. On the other hand, the rational loading dual catalysts (one is the reduction catalyst and the other is oxidation one) can further enhance photocatalytic activities of the materials. Nevertheless, these dual catalysts usually contain expensive noble metal elements. In view of the above, this project is dedicated to develop a general solution-phase self-assembly－ligand-anion ion exchange route to synthesize a series of porous Bi-based compounds nanosheets. Furthermore, dual non-precious metal catalysts derived from earth- abundant elements will be loaded on the surfaces of the as-synthesized porous Bi-based compounds nanosheets. The photocatalytic activities of porous Bi-based compounds nanosheets before and after loading dual catalysts under visible light irradiation will be systematically surveyed through the degradation of phenolic pollutants and water splitting. The synergistic catalytic effect among porous Bi-based compounds nanosheets, oxidation catalyst, and reduction catalyst will be explored as well. The transport mechanisms of photogenerated carriers on the interface of catalysts and the relationships between the structures of porous composite catalysts and the photocatalytic properties will be studied in detail. We hope to find the basic rules for fabricating highly efficient dual non-precious metals/porous Bi-based compounds nanosheets composite photocatalysts and provide new idea and method for designing and preparing new types of photocatalysts. The related studies have important academic significance and potential applications.

可见光响应的铋基光催化材料的研究备受关注。如何提高该类材料的光催化活性仍是当前研究的难点与瓶颈。制备多孔结构纳米片可以提升其光催化活性。但是如何发展普适的方法学制备该类材料却是一个科学难题。另一方面，合理负载双催化剂（氧化催化剂和还原催化剂）可进一步增强该类材料的性能，然而这类双催化剂往往需要使用贵金属。鉴于此，本项目旨在发展一种普适的液相自组装－配体-阴离子交换路线合成出系列多孔结构铋基化合物纳米片，研究其在共负载地球上元素丰富的非贵金属氧化催化剂(如Co-Pi）与还原催化剂石墨烯量子点前后，在可见光辐照下，催化降解水体中酚类污染物及分解水的光催化活性，探究双催化剂的协同效应，理解界面载流子的运输机制，揭示多孔异质铋基纳米片复合材料的结构与光催化性能之间的构效关系，为设计和制备高效、可见光响应、可循环利用的新型光催化材料提供新思路和新方法，相关研究具有重要的学术意义和潜在应用前景。

材料的光催化活性与其比表面积、晶面、光谱响应范围、光生载流子的有效分离、以及表面催化活性紧密相关。合理负载助催化剂（氧化催化剂和还原催化剂）可以促进光生载流子的有效分离，增加材料的表面催化活性，从而进一步提高材料的光催化性能。然而，这类催化剂往往需要使用贵金属。鉴于此，本项目开发了几种新型非贵金属助催化剂，包括碳量子点、Fe2O3、Co(OH)2及联吡啶合钴配合物。考虑到多孔纳米片及由二维纳米片与一维纳米线构筑而成的多维材料的结构优点，我们分别发展了一种普适的液相自组装－配体-阴离子交换路线合成出了多孔钒酸铋纳米片及由表面反应驱动的反应路线制备出了CdS纳米线/CdIn2S4纳米片多维结构。通过构筑异质结、实施边工程、采用晶面工程与缺陷工程相结合、利用助催化剂与掺杂相组合、设计多步光生载流子输运过程等策略有效提升了材料的光催化活性。系统研究了助催化剂的功能，物质组成、晶面、掺杂、比表面积、异质结、缺陷等因素对材料光催化性能的影响，揭示了光生载流子的传递过程与光催化反应机理，阐明了光催化材料结构与光催化性能之间的构效关系，为设计和制备高效、可见光响应、可循环利用的新型光催化材料提供新思路和新方法，相关研究具有重要的学术意义和潜在应用前景。