Zou Yan-Hong, Wang Hai-Ning, Meng Xing, Sun Hong-Xu, Zhou Zi-Yan
School of Chemistry and Chemical Engineering, Shandong University of Technology Zibo 255049 People's Republic of China
Nanoscale Adv. 2021 Jan 28;3(5):1455-1463. doi: 10.1039/d0na00814a. eCollection 2021 Mar 9.
Photoreduction of carbon dioxide (CO) provides an effective perspective for solving the energy crisis and environmental problems. Herein, two types of composite photocatalysts (TiO/ZIF-8) based on ZIF-8 and TiO have been designed and synthesized with the help of the grinding method and the solid-synthesis method. Both composite photocatalysts are employed for the photocatalytic reduction of CO. In composite photocatalysts prepared by the grinding method, ZIF-8 particles are distributed on the surface of TiO, and provide extra available spaces for storing CO, which is beneficial for improving their photoreduction performances. As a result, an enhanced CO formation rate of 21.74 μmol g h with a high selectivity of 99% is obtained for this family of composite photocatalysts the solid-gas mode without photosensitizers and sacrificial agents. For comparison, the other family of composite photocatalysts synthesized the solid-synthesis method possesses structures similar to ZIF-8, where TiO is encapsulated inside the framework of ZIF-8. This structural feature obstructs the contact between the active sites of TiO and CO, and leads to lower activities. The best CO formation rate of this family is only 10.67 μmol g h with 90% selectivity. Both the structural features of the two families of photocatalysts are described to explain their differences in photoreduction performances. The experimental finding reveals that different synthetic approaches indeed result in diversified structures and varied photocatalytic performances. This work affords a new scalable and efficient approach for the rational design of efficient photocatalysts in the area of artificial photosynthesis.
二氧化碳（CO）的光还原为解决能源危机和环境问题提供了一个有效的视角。在此，借助研磨法和固相合成法设计并合成了两种基于ZIF-8和TiO₂的复合光催化剂（TiO₂/ZIF-8）。两种复合光催化剂均用于CO的光催化还原。在通过研磨法制备的复合光催化剂中，ZIF-8颗粒分布在TiO₂表面，并为CO的存储提供了额外的可用空间，这有利于提高其光还原性能。结果，在无光敏剂和牺牲剂的固气模式下，该系列复合光催化剂获得了21.74 μmol g⁻¹ h⁻¹的增强CO生成速率和99%的高选择性。相比之下，通过固相合成法合成的另一系列复合光催化剂具有与ZIF-8相似的结构，其中TiO₂被封装在ZIF-8的骨架内。这种结构特征阻碍了TiO₂的活性位点与CO之间的接触，导致活性较低。该系列的最佳CO生成速率仅为10.67 μmol g⁻¹ h⁻¹，选择性为90%。描述了这两种光催化剂的结构特征，以解释它们在光还原性能上的差异。实验结果表明，不同的合成方法确实会导致结构多样化和光催化性能不同。这项工作为人工光合作用领域高效光催化剂的合理设计提供了一种新的可扩展且高效的方法。
