贵金属杂化二硫化钼/氧化石墨烯插层纳米复合物的可控合成与光催化性能研究

Recently, there is a bottleneck of the photocatalytic materials adsorbing visible light and near infrared region which has an extremely impact on the photocatalysis efficiency. Our proposed research is to fabricate novel composites of noble metal nanostructures hybridized MoS2/graphene oxide stacking layered nanosheets, extending the absorbed wavelength range into the visible light and near infrared region to enhance the photocatalytic performance and stability. Graphene oxide (GO) can be viewed as a surfactant to exfoliate MoS2 into layered nanosheets via chemical liquid and sonication synergistic function, further building stacking layered MoS2/GO nanohybrids, improving additional active edge sites of MoS2. The MoS2/GO stacking hybrids as scaffolds, large-scaled noble metal nanoparticles are deposited onto stacking layered hybrids via dopamine bio-inspired in situ growth strategy. GO is reduced to graphene, which can be as a bridge for electrons transition from valence band to conduction band, improving carriers transmission and localized electric field. This novel photocatalyst extends the absorbed wavelength range into the visible light and near infrared region via the localized surface plasmon resonance effect of noble metal nanostructures and band gap excitation, which is beneficial for the separation of electrons and holes, to enhance photocatalytic property and durability, providing a methodological reference for improving solar energy conversion efficiency and photocatalytic hydrogen evolution.

针对目前纳米材料光催化过程中吸收可见光效率较低、在近红外光谱区域几乎无响应的问题，本课题旨在构建新型贵金属杂化二维结构插层材料纳米复合物，拓展对可见光及近红外光谱的响应范围，提高光催化活性与稳定性。利用氧化石墨烯(GO)表面活性剂性质，实现对层状二硫化钼(MoS2)纳米片插层剥离，形成交替叠加结构插层复合物，以增加更多边缘催化活性位点，且有利于所负载贵金属纳米粒子的取向落位。该插层物为载体，采用多巴胺诱导原位合成形貌与尺寸可控的贵金属纳米颗粒。在多巴胺环境下GO被还原为石墨烯，促进载流子跃迁和局域电场增强；通过金属纳米粒子表面等离子共振与二维层状材料的带隙激发协同效应，实现复合物在可见光与近红外光谱的高效吸收。利用金属纳米粒子与原子层晶面相互作用，促进光生电子与空穴对的分离，避免光催化分解水时氢与氧的逆反应，极大地增强催化活性和稳定性，为提高太阳能转化效率以及光催化制氢产率提供方法学参考。

本项目面向研制合成异质结构层状纳米材料、贵金属纳米合金等化合物，利用材料的结构重组以提升其独特的物理化学性质。首先，采用化学溶剂法辅助超声振荡条件高效率地实现剥离边缘活性较高及尺寸均一的层状二硫化钼(MoS2)、二硫化钨(WS2)纳米片，表现出良好的稳定性、单分散性。其次，基于获取层状二硫化钼、二硫化钨纳米片作为骨架基体，利用水热法合成小尺寸二硫化钼薄片原位生长于上述层状纳米片表面，构建新型三维异质结构杂化纳米化合物，以此大幅度增加表面活性位点，进而大大提高该产物的催化性能及稳定性。比较地，金属纳米合金在形貌、结构及性能可控制备方面有着很大空间探寻，本课题在二元纳米合金、三元素杂化纳米合金的制备工艺方面进行大量实验，并获得最佳合成工艺路线，使其性能更加稳定且产量高，又可以实现催化及光电性能方面的极大提升，进一步实现纳米材料多功能化应用。