形貌可控纳米铌酸盐复合光催化剂的制备及可见光分解水制氢研究

In this project, visible-light-driven SnNb2O6 and Sn2Nb2O7 photocatalysts with controllable phase and morphology will be prepared by a simple hydrothermal synthesis method, and their photocatalytic hydrogen production activities can be improved by adjusting the reaction parameters systematically. Then, novel visible-light -driven M/SnNb2O6 and M/Sn2Nb2O7(M=TiO2、In2O3、CdS、C3N4) nanocomposite photocatalysts can be obtained by the simple hydrothermal synthesis method. The advantages of these semiconductor nanocomposites are as follows: first, the separation of photoinduced electrons and holes can be promoted efficiently,which can improve their photocatalytic activities; second, they have larger surface areas and more active sites, which can further improve their photocatalytic hydrogen production activities. In order to deeply understand the mechanism of photocatalytic water splitting into hydrogen, the effects of surface status and surface energy level of the photocatalysts on the interface charge transfer as well as the transfer mechanism of the photoinduced electron-hole pairs will be studied by in-situ experimental characterization techniques, such as field induced surface photovoltage spectroscopy (FISPS) and ultrafast spectroscopy(US). Base on the above research, the theoretical model of the relationship between the structure and performance of the photocatalysts will be established, and new ideas and new approaches will be provided for the development of novel and efficient visible-light-driven photocatalysts for water splitting.

本项目拟采用水热法制备物相和形貌可控的纳米SnNb2O6和Sn2Nb2O7可见光催化剂，通过调控合成工艺参数，优化其分解水产氢活性。其次，利用水热法合成新型纳米半导体复合型可见光催化剂M/SnNb2O6和M/Sn2Nb2O7(M=TiO2、In2O3、CdS、C3N4等)。利用半导体复合有效促进光生电子与空穴的分离，提高其光催化活性。而且，这种纳米半导体复合型光催化剂还具有大的比表面积和更多的催化反应活性位点等优点，可进一步提高其光催化分解水产氢活性。最后，采用场诱导表面光电压谱、超快光谱等原位表征手段，研究光催化剂表面态和表面能级对界面电荷转移的影响，以及光生电子-空穴对的转移机制等，更加深入理解光催化分解水制氢反应机理，建立光催化剂的结构与性能之间关系的理论模型，为研制新型高效的可见光分解水制氢光催化剂提供新思路和新途径。

发展新型高效稳定的半导体基纳米复合可见光催化剂是提高太阳能利用率，最终实现太阳能光催化技术产业化应用的关键。本项目按照课题目标和计划开展研究工作，基本完成项目的预期目标。本项目采用水热法、溶剂热法等成功制备了一系列新型高效的无机纳米半导体光催化剂，如SnNb2O6超薄纳米片、Sn2Nb2O7空心球、Nb4+自掺杂K4Nb6O17纳米片、CdS纳米颗粒/Cd纳米片异质结等，这些纳米结构光催化材料在太阳能光解水制氢方面表现出优异的催化活性和循环稳定性，为开发和设计新型高效的半导体基纳米催化材料提供了新思路和新途径。代表性工作如下：1）发展了一种简单、绿色的水热合成方法，成功实现了超薄二维SnNb2O6纳米片的可控制备，并表现出优异的可见光催化产氢性能；2）设计合成了一种具有空心结构的Sn2Nb2O7空心球光催化剂，空心结构有利于促进光的充分吸收，进而增强了其可见光催化产氢性能；3）发展了一种简便、高效的制备紫外光照射还原方法，实现了具有优异可见光响应的黑色Nb4+自掺杂K4Nb6O17纳米片的制备，在可见光照射下表现出优异的催化产氢性能；4) 发展了一种简单的氧化-硫化原位处理方法，成功实现了CdS纳米颗粒修饰的Cd纳米片复合型光催化材料的可控制备。与单组分的CdS纳米颗粒或者石墨烯/CdS纳米颗粒相比，这种新发展的CdS纳米颗粒修饰的Cd纳米片展现出更为优异的可见光催化产氢活性。