太阳能电助柔性TiO2 NTs/graphen/NBS网布制备及其净化污染物应用研究

In order to remove persistent aromatic pollutants in the environment, in-situ static growth of thin-layer graphene on flexible anodized TiO2 nanotubes (NTs) titanium mesh was proposed in this project. Narrow band gap semiconductor (NBS), serving as sensitizer, was grown on TiO2 NTs/graphene by pulsed electrodeposition technique. The ternary sandwich TiO2 NTs/graphene/NBS with ideal matching energy bands and high radical yields, constructing a novel mesh catalytic reaction system. The thin layer graphene with high conductivity would accelerate the photogenerated holes and electrons to transfer to their respective receptors and improve the photochemical quantum yields. The flexible titanium wire and cylindrical structure can significantly reduce the surface energy and internal stress of the TiO2 NT film, therefore, improve the physical stability of the catalysts. Sine super-long TiO2 NT grown on platy or sheet titanium substrate is easy to be broken and fell off, and has no resistance to bend. The ternary sandwich TiO2 NTs/graphene/NBS mesh system would effectively clear up the above problems. The porous structure of TiO2 mesh can increase the staying time of pollutant molecules on the surface of the catalysts and then increase the reaction probability. Coupling with solar electric device, an energy efficient, environment friendly and pollutant removal exhaustive photocatalytic device is designed by utilizing the conductivity, integrity and flexibility of the TiO2 mesh。

本项目以环境中难降解有机污染物去除为主要目标，以柔性阳极氧化TiO2 纳米管阵列( NTs）钛丝网布为基质，原位静态生长薄层石墨烯。再采用瞬时阶梯脉冲电沉积技术，在TiO2 NTs/graphene上原位快速生长伴随晶体分裂的硫属窄禁带半导体（Narrow-band-gap Semiconductor, NBS），构建具有理想能带匹配结构、高产自由基、可再生、三元夹心式TiO2 NTs/graphene/NBS柔性网布催化反应体系。处于夹心层的薄层石墨烯能提高光生空穴、光生电子向各自受主半导体的传递速率，提高光量子产率。钛丝的柔韧性与圆柱体结构，显著降低TiO2 膜的表面能与内应力，提高其物理稳定性，有效解决在板状、片状钛基上生长的超长TiO2 NT膜易破碎、脱落、怕弯折的问题。此外，利用TiO2网布导电性、整体性、柔韧性，耦合太阳能电助装置，搭建绿色低能耗深度净化污染物去除光催化器件。

该项目研究工作以环境中有毒有害污染物的低能耗、高效率去除为应用目标，针对高级氧化技术实用化过程中的短板，构建了一系列高活性、长寿命的环境功能催化剂，如集催化-导电电极“双效一体”的全固态、柔性阳极氧化TiO2钛丝、钛网；克服了钛板上催化层易脱落，怕弯折的难题。针对单相TiO2催化剂存在的光生电子迁移速度慢，光生电对易复合的本征缺陷，将超导石墨烯片层、窄禁带半导体（NBS）Cu2O, WO3, 超导 MoX2(X=S, Se)片层晶簇, 碳纳米管、金属纳米颗粒负载在TiO2 上，构建二元、三元“夹心式"复合异质结，对TiO2进行光、电特性增敏加强。以之为核心反应单元，设计并构建太阳能电助反应器。在外加偏压辅助下，调控其光生电对异向分离路径，进行水体中有机污染物、重金属离子的氧化或还原脱毒处理，取得理想的脱毒效果，并从理论角度进行突破性、详尽论证。本研究工作为光催化技术环境污染物脱毒应用中的低耗-长效-兼容-纵深拓展研究提供详尽的理论借鉴与分析。