基于高分子半导体的复合光催化剂的制备及可见光催化分解水制氢研究

Photocatalytic H2 from water using solar energy is one of the most efficient way to resolve the energy and enviromental problem in the 21st century. The key for solar energy utilization and photocatalytic H2 production is to search for stable visible-light responsible photocatalysts with high activity. This application focuses on Photocatalytic Splitting Water to Produce Hydrogen under Visible Light Irradiation. One of our strategies is to synthesis new polymer composites based on g-C3N4, P3HT, and/or PCBM as photocatalysts with high photocatalytic activity under visible light irradiation in order to utilize sunlight more efficiently. Another strategy is to promote the charge separation and transfer, suppress the charge recombination and enhance the photocatalytic activity by loading proper co-catalysts on the surface of the photocatalysts. It is also necessary to study the separation and migration of photo-excited electrons and holes in the photocatalysts, between the photocatalysts and reactants during photocatalytic reaction using ultraviolet photoelectron spectroscopy, electrochemical method, etc.

利用太阳能光催化分解水制氢是21世纪人类从根本上解决能源和环境问题的有效途径之一。研制在可见光范围内高活性的新型光催化剂是利用太阳能、实现光催化分解水制氢的关键。本项目拟制备高活性的基于g-C3N4、P3HT、PCBM等高分子半导体的复合光催化剂，研究其光催化性能；通过寻找合适的共催化剂担载在光催化剂的表面，促使光生电子-空穴的分离，避免高分子半导体的光降解，提高太阳光的利用率和光催化分解水产氢效率；利用紫外光电子能谱、电化学等方法研究高分子复合光催化剂的能带结构及光催化分解水制氢中光生电子-空穴的生成、迁移、复合机制，揭示反应机理及光催化效率等一系列光催化核心科学问题，为新型光催化剂的设计和光催化分解水制氢量子效率的提高提供理论指导。

项目组围绕当前国际上g-C3N4光催化剂可见光催化分解H2O制氢的基本科学问题，主要探索了通过高温焙烧尿素和硫脲混合物制备g-C3N4光催化剂、助催化剂Pt的担载方法对g-C3N4光催化剂的光催化产氢活性的影响；构建并制备了g-C3N4-Au-P3HT复合高分子半导体光催化剂，测试了该光催化剂的光催化性能，以及利用g-C3N4的-NH2基团将P3HT枝接到g-C3N4上，并测试了他们的光催化产氢活性。. 研究发现，尿素和硫脲乙混合物中硫脲的含量对所制备的g-C3N4光催化剂的吸光性能、能带结构、比表面积、荧光光谱、形貌等均有影响。当混合物中硫脲含量为2.44%左右时，所得g-C3N4光催化剂的光催化产氢活性最大。助催化剂Pt的担载方法对g-C3N4光催化剂的光催化产氢活性有较大的影响。. g-C3N4-Au-P3HT复合高分子半导体光催化剂的光催化产氢活性随着Au含量的增大先逐渐升高，在Au含量达1%左右达到最大。此外，光催化产氢活性随着P3HT含量的增大先逐渐升高，在P3HT含量达0.5%左右达到最大。. 通过FT-IR、UV-vis、XPS等表征技术确认了将P3HT枝接成功到g-C3N4上。P3HT枝接g-C3N4的光催化活性是g-C3N4的产氢速率的1.8倍。