Xiong Zhengwei, Liu Qian, Gao Zhipeng, Yang Jia, Zhang Xiaoqiang, Yang Qiang, Hao Chenchun
Joint Laboratory for Extreme Conditions Matter Properties, Southwest University of Science and Technology, Mianyang 621010, China.
Institute of Fluid Physics, China Academy of Engineering Physics, Mianyang 621900, China.
Inorg Chem. 2021 Apr 5;60(7):5063-5070. doi: 10.1021/acs.inorgchem.1c00093. Epub 2021 Mar 25.
Heterojunction photocatalysts, which can relieve the low carrier separation efficiency and insufficient light absorption ability of one catalyst, have received extensive attention. To construct an ideal heterojunction for photocatalysis, most previous studies focused on energy band structure engineering to prolong charge carrier lifetime and increase the reaction rates, which are critical to increase the photocatalytic activity. Here, the heterojunction interface was surprisingly found to be another important factor to affect the photocatalytic performance. We design three heterojunction interface models of α-FeO/BiO, corresponding to "ring-to-face", "face-to-face", and "rod-to-face". By tuning the heterogeneous interfaces, the photocatalytic performance of composites was significantly improved. On the basis of the type I energy band structures, the optimized face-to-face model realized a photocatalytic efficiency of 90.8% that of pure α-FeO (<30%) for degradation of methylene blue and a higher efficiency (80%) for degrading tetracycline within 60 min, which were superior to most Fe/Bi/O-based photocatalytic heterojunctions. Furthermore, the results disclosed that the enhanced performance was owing to the sufficient interfacial contact and low interfacial resistance of the face-to-face model, which provided sufficient channels for efficient charge transfer. This work offers a new direction of tuning heterojunction interface for designing composite photocatalysts.
异质结光催化剂能够缓解单一催化剂载流子分离效率低和光吸收能力不足的问题，因而受到广泛关注。为构建理想的光催化异质结，此前大多数研究集中在能带结构工程，以延长电荷载流子寿命并提高反应速率，这对提高光催化活性至关重要。在此，我们意外地发现异质结界面是影响光催化性能的另一个重要因素。我们设计了α-FeO/BiO的三种异质结界面模型，分别对应“环对面”“面对面”和“棒对面”。通过调整异质界面，复合材料的光催化性能得到显著提高。基于I型能带结构，优化后的面对面模型对亚甲基蓝的降解实现了90.8%的光催化效率（纯α-FeO的光催化效率<30%），对四环素的降解在60分钟内效率更高（80%），优于大多数基于Fe/Bi/O的光催化异质结。此外，结果表明性能增强归因于面对面模型有足够的界面接触和低界面电阻，这为高效电荷转移提供了充足的通道。这项工作为设计复合光催化剂调整异质结界面提供了新方向。
