针对复杂样品前处理要求，调控光(电)催化剂表界面结构：(1)纳米空心球内、外层选取等电点差异大的氧化物，双层表面电性不同；(2)层间夹入共催化剂，避免形成p-n结，迅速导出光生电子；(3)"双基团环状表面自组装"法修饰空心球，水杨酸衍生物的羧基、酚羟基同时与球表面羟基键合，形成六元环结构，催化过程中稳定性强；从而调控催化剂性能：(1)表面兼具"正电+负电+亲水+疏水"性，可同时吸附水溶性、疏水性、阴(阳)离子型样品；(2)增强对底物亲合力，突破非均相催化瓶颈(催化剂表面底物覆盖率低)；(3)可见光响应，增大捕光能力；(4)促进光生电子和空穴分离，提升催化活性，实现快速、完全降解有机物或光致氮磷化合物形态转化。 化学需氧量、总有机碳、总氮、总磷是衡量水体有机物污染和富营养化程度重要指标。项目可提供(1)纳米材料表界面结构多样化调控新方法和(2)水质监测样品前处理新技术-可见光光(电)催化。

According to the special requirements of sample pretreatment for water quality monitoring, the structure at the surfaces and interfaces of the photocatalysts or photoelectrocatalyst will be designed as follows. Two kinds of metal oxides (MOx and NOy) with enough difference in isoelectric point will be used as the inner and outer shell of double-shelled MOx@ NOy hollow spheres and then these two shells will be positively and negatively charged at a certain pH range, respectively. The co-catalyst will be inserted between two shells to avoid the information of p-n junction and to export photogenerated electrons quickly. The hollow nanospheres will be in situ self-assembled by salicylic acid and its derivatives (SAs) by the formation of stable surface complex with six-membered ring through an ester-like bond. The modificational functional groups are phenolic hydroxyl and carboxyl groups for SAs and surface hydroxyl groups on shells. The surface self assembly wil be stalbe during the catalytical process. These sandwich, double-shelled, and nanostructured MOx@ NOy hollow spheres will be used for the photocatalysis and photoelectrocatalysis to: (a) improve the surface characteristics of nanosphere with positively and negatively charged, hydrophilic, and hydrophobic to adsorb all kinds of samples at the same time; (b) enhance the affinity between organic pollutants and photocatalyst, i.e., to overcome the major obstacle of heterogeneous photocatalysis for the poor surface coverage of the pollutants on the catalyst; (c) expand the wavelength response range to the visible region, light harvesting capacity, and optical transmission path; and (d) promote the separation of photogenerated electrons and holes and then increase the photocatalytic and photoelectrocatalytic activity for the degradation of organic pollutants and species transformation of nitrogen and phosphorus in various compounds fastly and entirely. Chemical oxygen demand, total organic carbon, total nitrogen, and total phosphorus are important parameters for the assessment of organic pollution and eutrophication level. This project will offer: (a) a new method for the adjustment of the structure at the surfaces and interfaces of nanomaterials and (b) visible light-induced photocatalysis and photoelectrocatalysis by this hollow spheres and its application on water quality monitoring.