Xin Zhi-Kun, Gao Yu-Ji, Gao Yuying, Song Hong-Wei, Zhao Jiaqing, Fan Fengtao, Xia An-Dong, Li Xu-Bing, Tung Chen-Ho, Wu Li-Zhu
Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, 100190, P. R. China.
School of Future Technology, University of Chinese Academy of Sciences, Beijing, 100049, P. R. China.
Adv Mater. 2022 Jan;34(3):e2106662. doi: 10.1002/adma.202106662. Epub 2021 Nov 27.
Inspired by green plants, artificial photosynthesis has become one of the most attractive approaches toward carbon dioxide (CO ) valorization. Semiconductor quantum dots (QDs) or dot-in-rod (DIR) nano-heterostructures have gained substantial research interest in multielectron photoredox reactions. However, fast electron-hole recombination or sluggish hole transfer and utilization remains unsatisfactory for their potential applications. Here, the first application of a well-designed ZnSe/CdS dot-on-rods (DORs) nano-heterostructure for efficient and selective CO photoreduction with H O as an electron donor is presented. In-depth spectroscopic studies reveal that surface-anchored ZnSe QDs not only assist ultrafast (≈2 ps) electron and hole separation, but also promote interfacial hole transfer participating in oxidative half-reactions. Surface photovoltage (SPV) spectroscopy provides a direct image of spatially separated electrons in CdS and holes in ZnSe. Therefore, ZnSe/CdS DORs photocatalyze CO to CO with a rate of ≈11.3 µmol g h and ≥85% selectivity, much higher than that of ZnSe/CdS DIRs or pristine CdS nanorods under identical conditions. Obviously, favored energy-level alignment and unique morphology balance the utilization of electrons and holes in this nano-heterostructure, thus enhancing the performance of artificial photosynthetic solar-to-chemical conversion.
受绿色植物启发，人工光合作用已成为二氧化碳（CO₂）增值最具吸引力的方法之一。半导体量子点（QDs）或棒中量子点（DIR）纳米异质结构在多电子光氧化还原反应中引起了广泛的研究兴趣。然而，对于其潜在应用而言，快速的电子 - 空穴复合或缓慢的空穴转移及利用仍不尽人意。在此，首次展示了一种精心设计的ZnSe/CdS棒上量子点（DORs）纳米异质结构以水作为电子供体用于高效且选择性的CO₂光还原。深入的光谱研究表明，表面锚定的ZnSe量子点不仅有助于超快（≈2皮秒）的电子和空穴分离，还促进参与氧化半反应的界面空穴转移。表面光电压（SPV）光谱提供了CdS中空间分离的电子和ZnSe中空穴的直接图像。因此，ZnSe/CdS DORs光催化CO₂生成CO，速率约为11.3微摩尔每克每小时，选择性≥85%，远高于相同条件下的ZnSe/CdS DIRs或原始CdS纳米棒。显然，有利的能级排列和独特的形态平衡了该纳米异质结构中电子和空穴的利用，从而提高了人工光合太阳能到化学能转换的性能。
