原位组装沸石咪唑酯骨架对纸基ZnO纳米棒阵列光电性能的影响

Effect of in-situ assembling zeolite imidazolate frameworks on the photoelectric properties of paper-based ZnO nanorod array

  • 摘要: 性能卓越的光电极材料的设计制备对光电化学(PEC)技术的发展与应用至关重要。近年来,纸基光敏材料以其比表面积大、环境友好且成本低的优点被广泛研究。其中,作为一种高光电活性、高电子迁移率、无毒的光电极材料,纸基ZnO纳米棒被认为具有广阔的应用前景。然而,高载流子复合率及光腐蚀现象严重制约其光电性能的进一步提升。为降低光生载流子复合率并抑制光腐蚀,采用水热法在纸基ZnO表面原位组装沸石咪唑酯骨架材料-8 (ZIF-8),制备纸基一维ZnO/ZIF-8纳米棒阵列光电极。结果显示:ZIF-8均匀、致密分布在纸基ZnO表面,二者界面处无缝结合,利于促进界面电荷传输。同时,原位组装ZIF-8过程中,聚集大量氧空位的ZnO表面被刻蚀并转化为ZIF-8,利于抑制光腐蚀。此外,ZnO与ZIF-8能级匹配,二者结合形成异质结,可实现光生电子与空穴的双向传输,从而有效促进光生载流子分离。与纯ZnO纳米棒相比,纸基ZnO/ZIF-8复合材料展现出更高的光生载流子分离与传输效率、更大的光电流密度及更好的光稳定性。

     

    Abstract: The design and preparation of photoelectrode materials with excellent performance are crucial for the development and application of photoelectrochemical (PEC) technique. Paper-based photosensitive materials have been widely studied due to their large surface area, environmental friendliness and low cost. Among them, as one photoelectric material with high photoelectric activity, high electron mobility and non-toxic, paper-based ZnO nanorods have broad application prospects. However, the high recombination rate of charge carriers and photocorrosion seriously restrict the improvement of its PEC performance. Aiming to address these issues, zeolitic imidazolate frameworks-8 (ZIF-8) is in-situ assembled on paper-based ZnO through hydrothermal method to construct paper-based one-dimensional ZnO/ZIF-8 nanorod array. The results show that the ZIF-8 are uniformly and densely grown on the surface of ZnO nanorods, their seamless interface contact can facilitate the charge transport. Meantime, the ZnO surface enriched with abundant oxygen vacancy is etched and converted into ZIF-8, which can restrain the photocorrosion. Besides, due to the matched energy band structure, the formed ZnO/ZIF-8 heterojunction can realize the bidirectional transfer of photogenerated electrons and holes, thereby efficiently promoting the charge separation. Compared with pure ZnO, paper-based ZnO/ZIF-8 composites exhibit higher photocurrent density and enhanced photostability.

     

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