磷烯插层LDHs纳米反应器的可控构筑及其光催化二氧化碳转化为碳氢燃料的行为和机理研究

As one of the important components in the greenhouse gas, CO2 is potentially a cheap, rich, and renewable carbon resource. Therefore, the rational exploitation and utilization of CO2 to convert into valuable chemical products will bring great environmental and economic benefits to human society. The present project aims to construct a novel phosphene intercalated layered double hydroxides (LDHs) photocatalysis nanoreactor under visible light response with high stability and environmental friendliness. By tailoring the band gap structure of composite materials, the utilization rate of photoelectrons and the selectivity of reducing products in photocatalytic reduction of CO2 are expected to be enhanced significantly. The concerning key scientific and technological issues in the project will be investigated intensively, including the formation mechanism of the intercalated-structured nanoreactor, the adsorption capability of CO2 molecules between interfaces, the synergetic action of phosphene and LDHs, and the kinetics and thermodynamics laws during CO2 reduction. In addition, the mechanisms of electron migration between interfaces and photocatalytic behaviours will be explored. After completion of this project, it is expected to afford reliable scientific basis and technical support for photocatalytic CO2 conversion to fuels and other chemicals, and further diversify effective utilization of renewable carbon resources in our country.

CO2是温室气体的主要组成部分，同时又是一种廉价和丰富的潜在可再生碳资源。合理的开发和利用CO2使其转化为有价值的化学产品将给人类社会带来巨大的环境效益与经济收益。本项目旨在设计并构建一种高效稳定、环境友好、可见光响应的片层磷烯插层层状双氢氧化物（LDHs）光催化纳米反应器。通过对复合材料带隙结构的可控调节，提高纳米反应器光催化还原CO2过程中光生电子的利用率及还原产物的选择性，达到CO2向碳氢燃料的高效转化，实现碳资源的可再生利用。研究插层结构光催化纳米反应器形成机制；CO2分子在界面间的吸附能力；磷烯与LDHs还原CO2过程的协同关系；还原过程中反应热力学和动力学规律；界面间电子迁移机制和光催化转化行为机理等关键科学和技术问题。通过对本项目的研究，为光催化CO2向燃料等化学品转化提供可靠的科学依据和技术支撑，为推动我国CO2转化和碳资源的有效循环再生与利用提供可靠实践借鉴。

近年来，CO2引起的气候和环境问题日益突出, 将其高效燃料转化具有重要意义。本项目研究以层状双金属氢氧化物(LDHs)为光催化剂主体，利用元素掺杂、半导体复合、量子点改性等方法制得一系列具有高活性和良好产物选择性的LDHs基光催化剂用于还原CO2为CO和CH4等碳氢燃料；运用多样的表征手段研究所制备的LDHs基光催化剂的制备规律和各类理化特性；结合理论计算，究了CO2还原过程中的平衡、动力学、热力学性质和CO2的吸脱附特性、电子传输能力以及光催化还原CO2机理。如制备了碳量子点改性的花球状LDHs光催化剂，实验结果表明碳量子点改性的LDHs复合光催化剂活性优于体相LDHs材料。在这部分工作基础上项目组又系统研究了g-C3N4对碳量子点修饰的LDHs催化性能的影响。此外，使用g-C3N4、过渡金属氧化物、金属硫化物为客体光催化材料，与多种类LDHs复合制备了具有不同结构的异质结光催化剂，通过调控原料添加比例、光源范围以及牺牲剂用量，进一步研究所制备材料还原CO2的选择性以及还原产率。上述工作积累，为实现复杂的LDHs基光催化剂还原CO2过程提供一定的理论实践基础。