氮掺杂钙钛矿/氮掺杂石墨烯复合材料的构筑及其光催化还原CO2性能研究

CO2 is an important greenhouse gas, also a cheap and abundant resources of C1. It is of great significance to control the synthesis of catalytic materials which can achieve the conversion of CO2 efficiently under mild conditions. In this project, we will use sol-gel and hydrothermal technology to synthesize nanostructured perovskite and the high surface area graphene will be prepared by chemical reduction and chemical dissociation. Then the perovskite/graphene composites can be synthesized with ultrasonic, mechanical grinding and hydrothermal solvent thermal methods. After that, the N-doped perovskite/N-doped graphene composites will be prepared by NH3 high-temperature pyrolysis, sol-gel or/and hydrothermal synthesis technologies, and applied to CO2 photocatalytic reduction reaction. Based on the improved effect of nitrogen doping on the energy band gap of both perovskites and graphene materials, combining with CO2 photocatalytic process energy band demand, the formation mechanism, modulation mechanism and synergistic effect of the compound materials will be investigated. The highly efficient catalytic materials for CO2 photocatalytic reduction will be synthesized according to the principle of energy band matching, combining with the modulation mechanism of nitrogen doping composite materials. The structure-activity relationship and the catalytic mechanism will be revealed. The research is of great value in controlling the synthesis of nitrogen-doped perovskite/nitrogen-doped graphene composites and the application in efficient photocatalytic reduction of CO2 under mild conditions.

CO2是重要的温室气体，也是廉价而丰富的C1资源，控制合成能够在温和条件下实现CO2高效还原转化的催化材料对解决能源环境问题意义重大。本项目拟采用溶胶凝胶、水热技术合成纳米结构钙钛矿，采用化学还原法、化学解离法制备大比表面积石墨烯，综合使用超声、机械研磨、水热溶剂热方法制备钙钛矿/石墨烯复合材料。通过一步NH3高温热解、溶胶凝胶或水热合成技术，构筑合成氮元素同时掺杂的钙钛矿/石墨烯复合材料，并将其用于CO2光催化还原反应。基于氮掺杂对钙钛矿及石墨烯材料能带间隙等性能的改善作用，结合CO2光催化过程能带需求，调制氮掺杂型复合材料并深入探究复合材料的形成机理、调制机制与协同效应。依据能带匹配原理，结合氮掺杂复合材料调制机制，构制CO2光催化还原高效催化剂，揭示构效关系，阐明催化机理。该课题的研究对控制合成氮掺杂钙钛矿/氮掺杂石墨烯复合材料及其在温和条件下实现高效光催化还原CO2具有重要价值。

CO2是重要的温室气体，也是丰富而廉价的C1资源，控制合成在温和光照条件下实现CO2高效还原转化的催化材料对解决环境与能源问题具有重大意义。项目采用水热、溶胶凝胶、固相研磨等技术控制制备了具有稳定晶相结构和良好物理化学性能的系列钙钛矿材料，并以尿素、硫脲、氮气等为氮源，控制合成氮掺杂型钙钛矿材料，进一步利用石墨烯优异的表面及理化性质构筑了氮炭共掺杂型钙钛矿复合催化材料，并将其用于CO2光催化还原过程。研究发现A、B金属元素位掺杂对钛基钙钛矿材料具有不同的影响机制，同时发现复合催化剂体系中异质结的构建能够有效提升反应过程中的光电子传输效率，从而提升CO2光催化还原性能。研究获得了所述复合材料的制备工艺参数及调制机制，并依据能带匹配理论构筑了CO2光催化还原高效钙钛矿复合催化剂，揭示了催化剂体系中氧空位、异质结等与催化效能之间的构效关系并阐明了CO2光催化过程所遵循的卡宾过程催化机理。氮掺杂能够拓展钙钛矿材料的光响应范围，影响其光吸收性能。本项目的研究对控制合成多元掺杂型钙钛矿复合材料及其在温和条件下实现高效光催化还原CO2具有重要价值。