光催化苯制苯酚用水滑石纳米催化剂的设计和性能调控

Currently, phenol is produced in industry generally suffering high energy consumption conditions, with several steps and low selectivity, thus, phenol synthesis from benzene in a one-step reaction with high benzene conversion and high phenol selectivity has become scientific important and is still a big challenge. Photocatalysis featured by its high catalytic efficiency in activating chemical bonding intensively under mild reaction conditions, has become a green technology with promising technical prospect. In this project, ultrathin layered double hydroxides (LDHs) naonsheets will be controllablely synthesized, through carefully intercalating photoactive elements into LDH layer, and surfactants in the interlayer using a simple and scale-up coprecipitation method that involves separate nucleation and aging steps (SNAS). The corresponding components, the thickness, lateral size as well as the intercalating species of nanosheets can be adjusted, resulting in the controllable properties of the band gap, surface defects and surface hydrophobicity of LDHs, to optimize the photooxidation activity of benzene to phenol by using H2O as oxidation agent. Besides, the selectivity of phenol can be well promoted by adding phenol-philic LDH-typed adsorbent, and this strategy leads phenol easily separate from the surface of photocatalysts, and avoids the overoxidization. Through combination the theoretical calculation with experiment study, the relationships between the structures-properties-performance-mechanism will be systematically investigated, providing general rules for the rational design of highly efficient photocatalysts for phenol synthesis.

目前工业上传统苯制苯酚技术存在能耗高、路线繁琐、选择性低等问题，开发一步法绿色、高效苯制苯酚是该领域的研究重点和挑战。而光催化技术具有可以在常温常压下深度、高选择性活化化学键的优势，成为一种具有重要应用前景的绿色技术。本项目拟以非贵金属超薄层状水滑石（LDHs）纳米片为研究主体，通过在其层板中引入光催化活性元素，对层间插层改性，利用易于工业化放大的成核晶化隔离法，实现对于LDHs组成、厚度堆叠、粒径大小、层间疏水性分子插层的调控，进而达到对能带结构、缺陷位、以及表面疏水性的精准调控，利用H2O作为氧化剂，实现对于苯制苯酚的高效光催化转化；进一步，为避免产物苯酚的过度羟基化，通过引入吸附型LDHs，实现对苯酚在光催化剂表面的分离脱附，获得高效光催化苯制苯酚LDHs基催化剂。同时采用理论与实验相结合的方法，深入研究LDHs材料的构效关系及光催化反应机理，为开发高效光催化剂提供设计原则。

苯酚广泛应用于生产酚醛树脂、己内酰胺等重要化学产品，是染料、制药、香水、农药等精细化学品的重要原料。开发一步法苯羟基化制苯酚的绿色工艺是化工十大难题之一。本项目围绕超薄层状水滑石（LDHs）纳米片光催化一步法苯制苯酚为研究主体，可控制备了不同金属组成的超薄LDHs纳米片催化剂。深入对LDHs纳米片组成、形貌、结构进行表征，结合理论计算和光催化苯制苯酚反应，明确了超薄LDHs纳米片的缺陷结构和缺陷浓度，暴露活性晶面和表面亲疏水的特性，提升了光生电子和孔穴的生成速率，从而促进了光催化苯制苯酚的反应。通过对LDHs纳米片的合成过程优化，实现了实验室规模化放大合成超薄LDHs催化剂，实现了100-1000g LDHs催化体系，为工业制备光催化苯制苯酚催化剂提供了基础。进一步，将光催化苯制苯酚的LDHs催化剂拓展应用于光催化活化C=O，C-H，C=C键，实现了CO2,CH4,环辛烯等小分子高值转化，为LDHs催化剂的其它光催化应用探索了可能性。综上所述，本项目的开展对于可控合成、规模化合成光催化苯制苯酚的超薄LDHs纳米片催化剂，实现工业上一步法制备苯酚具有重要意义。研究工作以第一作者或通讯联系人在 Joule, Chem sci, Adv. Funct. Mater., Appl. Catal. B: Environ., Cell Rep. Phys. Sci., Chem Commu., Green Chem., Chem. Eng. J. Ind. Eng. Chem. Res., Chem. Eng. Sci.等SCI学术刊物发表论文28篇，申请5项国家发明专利，授权1项国家发明专利。在本项目的支持下，项目负责人连续四年（2019-2022）入选科睿唯安“全球高被引学者”，入选思唯尔2021 “中国高被引学者”，获得2021年中国科技期刊卓越行动计划奖励，获得2021年中国感光学会自然科学技术特等奖，以及石化联合会科技进步二等奖，获得2019年国家自然基金委优秀青年基金。担任Acta. Phys. Chim. Sin., Trans. Tianjin Univ., SmartMater等学术期刊编委或青年编委。