Li Huiyi, Chen Renli, Sun Liang, Wang Yanru, Liu Qilong, Zhang Qun, Xiao Chong, Xie Yi
Hefei National Research Center for Physical Sciences at the Microscale, iChEM, University of Science and Technology of China, Hefei, Anhui, 230026, China.
The Instruments Center for Physical Science, University of Science and Technology of China, Hefei, Anhui, 230026, China.
Adv Mater. 2024 Nov;36(44):e2408778. doi: 10.1002/adma.202408778. Epub 2024 Aug 30.
In the pursuit of successful photocatalytic transformations, challenges persist due to limitations in charge carrier utilization and transfer efficiency, which stemming from rapid recombination. Overcoming these limitations necessitates the exploration of novel mechanisms that enhance the effective separation of photogenerated electron-hole pairs. Herein, deviating from the conventional approach of enhancing carrier migration to separate photogenerated charges and extend their lifetime, the proposal is to directly prevent the recombination of photogenerated electrons and holes by forming hole polarons. Specifically, disordered pores are introduced on the surface of KTaO ultrathin sheets, and the clear-cut evidences in electron paramagnetic resonance, photoluminescence, and ultrafast spectroscopy unambiguously confirm the enhanced carrier-phonon coupling, which results in the formation of hole polarons to impede the recombination of photogenerated electron-hole pairs. Taking the challenging nitrogen oxidation reaction as an example, it is found that the hole polarons in atomic-disordered pore KTaO ultrathin nanosheets trigger outstanding photo-oxidation performance of nitrogen (N)to nitrate, with a nitrate-producing rate of 2.1 mg g h. This scenario is undoubtedly applicable to a wide variety of photocatalytic reactions due to the common challenge of charge carrier recombination in all photocatalytic processes, manifesting broad implications for promoting photocatalysis performance.
在追求成功的光催化转化过程中，由于电荷载流子利用和转移效率的限制（这源于快速复合），挑战依然存在。克服这些限制需要探索新的机制，以增强光生电子 - 空穴对的有效分离。在此，与通过增强载流子迁移来分离光生电荷并延长其寿命的传统方法不同，本文提出通过形成空穴极化子直接防止光生电子和空穴的复合。具体而言，在KTaO超薄片表面引入无序孔，电子顺磁共振、光致发光和超快光谱等明确证据清楚地证实了载流子 - 声子耦合增强，这导致形成空穴极化子，从而阻碍光生电子 - 空穴对的复合。以具有挑战性的氮氧化反应为例，发现原子无序孔KTaO超薄纳米片中的空穴极化子引发了将氮（N）氧化为硝酸盐的出色光氧化性能，硝酸盐生成速率为2.1 mg g⁻¹ h⁻¹。由于在所有光催化过程中电荷载流子复合是一个共同挑战，这种情况无疑适用于各种各样的光催化反应，这对提高光催化性能具有广泛的意义。
