Xu Linpeng, Zhao Yun, Li Zhanfeng, Wu Jianhong, Cui Jiewu, Tian Bining, Wu Yucheng, Tian Yue
Institute of New Carbon Materials, College of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan 030024, China.
Institution of Energy Innovation, College of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan 030024, China.
ACS Appl Mater Interfaces. 2022 Jun 8;14(22):25278-25287. doi: 10.1021/acsami.2c01781. Epub 2022 May 27.
Construction of heterostructures is one of the most promising strategies for designing photocatalysts for highly efficient solar hydrogen (H) production because the introduction of an electron-donating counterpart contributes to more effective photon absorption, while the heterostructures benefit spatial carrier separation. However, the hole-transfer rate is usually 2-3 orders of magnitude slower than that of the electron-transfer rate within the heterostructures, ensuing serious charge recombination. Here, we find the energy band offset-driven charge-transfer behavior in a donor-acceptor (D-A)-conjugated polymer/CdS organic/inorganic heterostructure and realize hole-transfer improvement in cooperation with a further hole removal motif of poly(3,4-ethylenedioxythiophene) polystyrene sulfonate. The photocatalytic H production activity is increased by nearly 2 orders of magnitude with the apparent quantum yield hitting 80% at 450 nm without co-catalysts. Ultrafast transient absorption together with surface photovoltage characterizations consolidates the hole extraction mechanism. The intimate bond formed at the interface between the polymer and the inorganic semiconductor acts as an interpenetrating network at the nanoscale level, thus providing a charge-transfer freeway for boosting charge separation.
构建异质结构是设计用于高效太阳能制氢的光催化剂最具前景的策略之一，因为引入供电子组分有助于更有效地吸收光子，而异质结构有利于空间载流子分离。然而，在异质结构中，空穴转移速率通常比电子转移速率慢2 - 3个数量级，导致严重的电荷复合。在此，我们发现了供体 - 受体（D - A）共轭聚合物/CdS有机/无机异质结构中能带偏移驱动的电荷转移行为，并通过聚（3,4 - 乙撑二氧噻吩）聚苯乙烯磺酸盐的进一步空穴去除 motif实现了空穴转移的改善。在没有助催化剂的情况下，光催化产氢活性提高了近2个数量级，在450 nm处的表观量子产率达到80%。超快瞬态吸收以及表面光电压表征证实了空穴提取机制。聚合物与无机半导体之间界面处形成的紧密键在纳米尺度上充当互穿网络，从而为促进电荷分离提供了电荷转移通道。
