Liu Ying,Dai Fangxu,Zhao Ruiyang,Huai Xudong,Han Jishu,Wang Lei
A novel water-soluble core/shell/shell CdSe/CdS/ZnS quantum dot (QD) is prepared and employed as photocatalysts in the water splitting for hydrogen production. The combination of CdSe with CdS shell and ZnS shell effectively enhances the light harvest ability of the photocatalyst in the visible region, facilitates the separation and transfer of photoinduced electrons and holes and inhibits the recombination of photogenerated electron–hole pairs. The results of photocatalytic hydrogen production show that the amount of hydrogen produced by CdSe/CdS/ZnS QDs increases significantly within 7 h compared with CdSe QDs and CdSe/CdS QDs. In addition, the excellent recyclability of the photocatalyst makes it more promising for practical application.
Kanghong Wang,Yi Tao,Zikun Tang,Daniele Benetti,François Vidal,Haiguang Zhao,Federico Rosei,Xuhui Sun
Colloidal Quantum dots (QDs) are considered promising light harvesters for photoelectrochemical (PEC) hydrogen generation devices due to their size tunable optoelectronic properties. However, the solar-to-hydrogen (STH) efficiency and long-term stability of devices based on QDs are still relatively low, thus limiting the commercial development. These limitations are attributed to the limited absorption range of QDs, unfavorable band energy alignment and photo-oxidation. Here we propose and realize two core/multiple-shell architecture based on CdSe/CdS/ZnS QDs. The shell composition is optimized with gradient layers, forming CdSe/CdSe x S 1−x /CdS/Zn y Cd 1−y S/ZnS core/multiple-shell structures, which reduces the surface traps and defects of QDs and simultaneously suppresses exciton recombination by providing intermediated alloyed interlayers . The PEC device based on a mesoporous TiO 2 sensitized with two types of core/multiple-shell QDs exhibited an outstanding saturated photocurrent density of 20.5 mA/cm 2 for alloyed core/multiple-shell QDs, under one sun illumination (AM 1.5 G, 100 mW/cm 2 ). To our knowledge, this is comparable to the highest value reported so far for the PEC devices based on colloidal QDs. In addition, the as-prepared PEC devices exhibited excellent stability, maintaining ~93.4 % of the initial photocurrent density after 2-hour continuous illumination (100 mW/cm 2 ). This work provides an efficient approach for improving the performance of PEC devices through QDs structure engineering.
危险品化学品经营许可证（带存储）