基于光纤布能石墨烯气凝胶原位负载蜂窝状(SC-X)@GA/OF多孔电极的精密构建及CO2光电还原微观协同催化机制

The reduction of CO2 had important significance in energy development and environmental management. In this study, the optical fiber energy-distribution graphene aerogel supported honeycomb (SC-X)@GA/OF electrode (SC: emiconductor; X: doping element; GA: graphene aerogel; OF: optical fiber) porous electrode were precisely constructed by microemulsion template in-situ self-assembly technique. The catalytic efficiency of CO2 was improved due to the all-around energy-distribution property of optical fiber, the high electric conductivity and diffusion absorption property of graphene aerogel as well as the gas collection, light concentrating and high electron conduction performance of honeycomb porous structure, the doped heterojunction effect, the optical fiber energy-distribution effect and the microsynergic catalytic effect. Moreover, the synergy mechanism was discussed, and the structure-function relationship was optimized. The study was focused on the relationship between the preparation technology, structure and performance of electrode. The precise design and construction of microstructure such as phase, atom and electron of electrode surface and interface, were investigated. The interaction mechanism and control between electrode surface and interface characters (such as microstructure and chemical composition) and environment were studied. In addition, the optical fiber screening and layout, the selective activation, reduction path and kinetic process of reactants were also investigated to find out the electrode materials with high activity and excellent performance for repeated use. The researches provided theoretical basis and technology foundation to explore the preparation of such electrode materials, the control of surface and interface behavior, the microsynergistic catalytic mechanism and their practical application in gas phase catalysis

光电催化CO2还原在能源开发与环境治理方面具有重要意义。本课题利用微乳液模板原位自组装技术精密构建光纤布能石墨烯气凝胶原位负载蜂窝状(SC-X)@GA/OF多孔电极(SC:半导体;X:掺杂元素;GA:石墨烯气凝胶;OF:光纤)。利用光纤全方位布能特性，石墨烯气凝胶高导电率与高扩散吸附特性，蜂窝状多孔的集气聚光与高电子传导性、结合异质表界面效应、光纤布能效应、微观协同催化效应、提高CO2还原效率，阐述催化机制和优化构效关系。本课题重点研究电极制备工艺与其结构、性能的关系；研究电极表界面物相、原子电子等微纳结构的精密构建、表界面特性与环境相互作用机制及调控，光纤筛选与布置，反应物选择活化、还原路径及动力学过程，寻找高活性和优异重复使用性能的电极材料。本课题研究将为探索此类电极材料制备、表界面行为调控与微观协同催化机制及其在气相催化领域的实际应用提供理论依据和奠定技术基础。

能源危机与环境污染是影响人类可持续发展的两大重要问题。CO2即使一种储备量大的碳资源，也是温室气体，将其催化加氢转化为碳基燃料，不但能够解决能源危机，又能起到调节温室效应目的，具有能源开发与环境治理的重要意义。虽然CO2电催化具有产物选择性高和可控性好的优点，但存在缺陷是能耗大、也产生了大量废液，导致环境污染等问题。因此，人工光合作用成为CO2 催化还原重要研究方向。但目前光催化反应体系在降低反应势垒、提高转化率及控制选择性方面还力不从心。为此，光电催化技术应运而生。但至今为止，大量的工作还主要集中在采用无孔导电基体负载半导体薄膜及液相条件下光电催化方面。因此，采用多孔导电基体负载蜂窝状改性半导体多孔电极在气相催化领域倍受关注。但值得关注的是，迄今还没有制备光纤布能石墨烯气凝胶原位负载蜂窝状多孔复合电极材料的有效方法。为此，本课题通过水热技术辅助制备石墨烯气凝胶/光纤(GA/OF)为基体，再利用多个表面活性剂分子与可聚合无机源（SC 半导体和X 掺杂剂）相互聚集形成的有序聚集体，通过原位生产实现 “微乳液–SC–X 前驱体”在GA/OF炭质薄片上，最后通过低温热处理生成蜂窝状(SC–X)@GA/OF多孔复合纳米材料。本课题合成的(C3N4-Bi2O3)@GA, (C3N4-CoSe2)@GA、(MT-Ag)@GA/OF、(ZnO-Pt)@GA/OF和(BiOI-Au)@GA/OF等具有高的比表面积达（242m2/g）,低的带隙能达（2.3eV），高的催化活性达（CO产生效率为11.36μmol•g-1•h-1）而石墨烯气凝胶负载NiAl-LDH/g-C3N4的CO产生效率更高达28.83μmol•g-1•h-1。提出了掺杂降低能级与蜂窝状载体双协同提高催化活性方法；揭示了微异质结导致Ag掺杂介孔TiO2/石墨烯气凝胶， Bi2O3改性C3N4/石墨烯气凝胶，CoSe2改性C3N4/石墨烯气凝胶，Au掺杂介孔BiOI/石墨烯气凝胶具有高效催化活性作用机制及其构效关系；发明了精准构建原位生成蜂窝状石墨烯气凝胶负载(MT-Ag)，(C3N4-Bi2O3), (C3N4-CoSe2)功能单位简便方法，实现了高效可见光催化性能。本课题的研究结论为石墨烯气凝胶原位负载介孔类复合功能材料的制备及在气相光催化领域的实际应用提供理论依据和奠定实验基础。