亲疏水调变钙钛矿/石墨烯气凝胶的构建及光热协同催化性能研究

The perovskite/graphene aerogel as a novel class of environment purification material has been receiving special attention due to their specific photo-thermal properties and inter-modulation, which is important for solar energy utilization and energy conversion. In this regard, conducting systematic studies on the bulk composite visible-light-driven photocatalyst and synergistic photothermal catalytic performance is imperative for perovskite/graphene composites related photocatalytic research, which could significantly enrich the categories of photocatalytic purification as well as boost their potential applications. Inspired by our recent investigations on photocatalytic composites, this proposal centers on carrying out an innovative study on the hydrophilic and hydrophobic regulation of perovskite/graphene aerogel, as well as on the synergistic photo-thermal catalytic performance, as well as on the new interface effects of graphene aerogel compound system, aiming to gain a deep understanding of the mechanism of enhanced photocatalytic degradation activity. This proposal mainly encompasses the following sections: (i) Controllable preparation of bulk perovskite/graphene aerogel composite based on hydrophobic-regulation and synergistic photothermal catalytic; (ii) The influencing mechanism of hydrophilic and hydrophobic regulation on the adsorbability and photo-thermal conduction of perovskite/graphene aerogel composite; (iii) Construction of the novel synergistic photo-thermal catalytic system for the efficient treatment of antibiotic wastewater; (iv) The mechanism of enhanced photocatalytic performance induced by the coexistence and competition between multiple regulatory factors in perovskite/graphene aerogel composites.

钙钛矿/石墨烯气凝胶蕴含特殊的光热特性与调变性能，相关研究是环境净化材料的热点方向之一，也对太阳能利用及能量转换等应用领域的发展具有重要意义。开展宏观整体块状复合可见光催化剂及其光热协同催化性能的研究工作是钙钛矿/石墨烯复合光催化材料发展的一个必然趋势，也是丰富光催化降解体系，并推动其应用的关键所在。本申请以申请人近年来在复合光催化材料方面的研究工作为基础，着重开展对钙钛矿/石墨烯气凝胶亲疏水的调控及光热协同催化性能的创新研究，深刻理解其光催化降解活性增强的机制。主要包括：（1）基于亲疏水调控和光热协同催化的宏观整体钙钛矿/石墨烯复合气凝胶的制备；（2）亲疏水调控对钙钛矿/石墨烯复合气凝胶吸附性和光热传导性能的影响机制；（3）构建高效降解抗生素废水的光热协同催化新体系；（4）钙钛矿/石墨烯复合气凝胶结构中多种调控因素共存与竞争引起的光催化活性增强效应与机制。

基于表面化学性质对钙钛矿/石墨烯光热及催化性能的重要性，本课题通过对其亲疏水性调控来实现特定的光热转化，实现难降解废水的绿色低成本净化。原位合成了具有宏观3D结构的自漂浮型钙钛矿Bi2WO6/石墨烯气凝胶光催化剂，探究制备过程因素对其微观结构及性能的影响。分别利用盐酸、冰醋酸和硝酸三种不同酸诱导PDI自组装到还原氧化石墨烯(rGO)的表面，获得兼具光催化降解和光热水蒸发的双功能表面自敏化的PDI/rGO复合膜，构建高效降解抗生素废水的光热协同催化新体系。0.5个可见光照射下，该复合膜对10mg/L盐酸环丙沙星(CIP)的降解率为94.31%，其相应的界面蒸汽生成效率为10.92%。结合微观结构表征和光电化学性能测试，探究多种因素共存与竞争引起的光热催化活性增强效应与机制：（1）rGO的加入将纳米PDI的光吸收范围扩大到近红外波段；（2）纳米PDI与rGO之间的π-π相互作用调节了能带结构和氧化还原电位；（3）上层纳米PDI的禁带电子和空穴弛豫到禁带边缘，将过剩的能量转化为热，实现了光热转换。通过冷冻干燥-煅烧法制备了多孔亲/疏水性纤维素石墨烯气凝胶(CGA)，探究了光源功率密度以及开放与密闭系统的环境因素对该气凝胶光热水蒸发性能的影响。在1个太阳辐射4 h，该气凝胶从模拟或实际海水中可蒸发7.2 kg/m2的水。由于界面蒸发以及重金属离子与含氧官能团之间形成氢键和螯合键，CGA可以有效减少重金属污水的体积量，获得无生物毒性的清洁水。气凝胶有效的光热效应主要归因于疏水rGO的光热转化，亲水性纤维素片层交联形成的相互连通的多孔结构以及片层孔洞等结构作为水分传输通道。该研究为难降解废水的高效处理与资源化利用提供一定的理论基础。