石墨相氮化碳基异质结构材料调控与水泥表层可见光自清洁

Environmental crisis and energy issue become more and more severe that put forward great demand on the development of highly efficient self-cleaning cement based materials under visible-light irradiation. In this project, founded on visible-light photocatalytic property of graphite carbon nitride, graphite carbon nitride based heterostructure materials are fabricated and in-situ bonded with cement via diverse adjustment and control manner to approach highly effective photocatalytic self-cleaning performance on the surface of cement. The energy level of graphite carbon nitride based heterostructure materials is matchably adjusted. Multi-dimensionally configurable graphite carbon nitride based heterostructure materials with silanol, amine and carboxyl groups as binding sites are fabricated. The mechanism on the enhancement of visible-light photocatalytic response for graphite carbon nitride via restraining the recombination of charge carriers is then illuminated. Based on the composition and structure features of cement, chemical bonding of graphite carbon nitride based heterostructure materials with cement is adjusted with the bonding mechanism studied, approaching the in-situ stable bonding at their interface. Relying on the nucleation and densification effect of nanomaterials to cement, the influences of graphite carbon nitride based heterostructure materials on hydration, hardening and durability of cement are studied to improve the durability of the surface of cement. Also, the effect of graphite carbon nitride based heterostructure materials on phtocatalytic response of cement is revealed to achieve highly efficient visible-light photocatalytic cleaning performance on the surface of cement in the hope of providing theoretical basis and technical guidance on research and development of novel photocalytic self-cleaning cement materials.

针对全球日益突出的环境污染和能源短缺对水泥基建筑材料可见光高效自清洁的重大需求，本项目拟基于石墨相氮化碳的可见光催化作用，构建及调控石墨相氮化碳基异质结构材料，获得其与水泥的原位耦合，实现水泥表层的高效可见光催化清洁。匹配调控石墨相氮化碳基异质材料的能级分布，制备以硅羟基、胺基、羧基等为连接位点的多维构型异质结构材料，建立抑制载流子复合的异质结构对可见光的响应增强机制；根据水泥的组成及结构特性，利用化学键合调控水泥水化产物与异质结构材料的耦合方式，确定界面连接作用机制，实现异质材料在水泥表层的原位固载；依据纳米材料的晶核效应及密实作用，探究石墨相氮化碳基异质结构材料对水泥表层水化及耐久性的影响机制，获得水泥表层的耐久性提升；研究异质结构材料对水泥表层光催化响应的作用规律，实现水泥表层可见光催化的高效自清洁，为研发新型光催化清洁水泥材料提供理论指引与技术支持。

环境污染和能源短缺是可持续发展的重要问题，开发利用新能源，解决环境污染十分必要。作为用量最大、使用范围最广的重要建筑材料，功能性自清洁水泥可有效降解污染物，可作 为能源短缺及环境污染问题解决的新媒介。项目基于石墨相氮化碳的可见光催化作用，调控构建石墨相氮化碳及其异质结构材料，获得其与水泥的原位耦合，实现水泥表层的高效可见光催化清洁。基于热缩合法，匹配调控石墨相氮化碳形貌结构及性能，通过能级分布调控构建石墨相氮化碳-氧化硅、氧化钛、钒酸铋等系列石墨相氮化碳基异质材料，获得抑制载流子复合的异质结构对可见光的响应增强机制。根据水泥的组成及结构特性，通过羟基、羧基等基团接枝，连接层构架等方式，获得石墨相氮化碳及其异质结构材料在水泥表层的原位固载。基于构建的纳米石墨相氮化碳及其异质结构材料，研究了其对水泥表层形貌结构的作用影响，获得了石墨相氮化碳及其异质结构材料对水泥表层光催化响应作用规律及动力学模型，明确了石墨相氮化碳其异质结构材料精准调控构建的必要性，实现了水泥表层可见光催化的高效自清洁及长效耐久服役。项目研发的石墨相氮化碳及其异质结构材料制备条件温和、方法简单稳定，可有效提升石墨相氮化碳的可见光催化响应，并可成功构建其与水泥基材料的固载结合，为设计及研发高性能自清洁水泥基材料提供了理论指引与技术支持。