Yang, Rui-Gang, Fu, Yao-Mei, Wang, Hai-Ning, Zhang, Dao-Peng, Zhou, Zhen, Cheng, Ying-Zhi, Meng, Xing, He, Yu-Ou, and Su, Zhong-Min
• MOF/COF hybrid photocatalysts are prepared through the simple grinding method. • TpPa/ZIF-8 photocatalysts exhibit excellent performances in pure and diluted CO 2. • The role of –OH groups on photocatalytic performances is proposed and verified. It remains challenging to design and synthesize porous crystalline photocatalysts for photocatalytic reduction CO 2 with high efficiency. Herein, a Schiff-based covalent organic framework (TpPa-1) is explored to combine with a metal–organic framework (ZIF-8) via a simple and fast method (the grinding method) firstly, generating a series of photocatalysts TpPa/ZIF-8. The photocatalytic performances of the as-synthesized photocatalysts TpPa/ZIF-8 are evaluated through a gas–solid reaction mode without photosensitizers and sacrificial agents, exhibiting excellent photocatalytic activities toward CO 2 in pure CO 2 and 10% CO 2 atmosphere, especially in 10% CO 2 environment. Therefore, the experimental result presents that TpPa/ZIF-8 can obtain the CO formation rates of 43.94 μmol·g−1·h−1 at a pure CO 2 environment and 84.87 μmol·g−1·h−1 in 10% CO 2 atmosphere, approximately 2 times and about 6 times larger than those of TpPa-1 in the pure CO 2 and 10% CO 2 atmosphere, respectively. The interesting phenomenon inspires us to investigate the structural factors affecting the photocatalytic activity, and hydroxyl groups from TpPa-1 are suspected to play an important role in the significantly improved photoreduction performance of CO 2 in 10% CO 2 atmosphere. The controlling examples TFPa/ZIF-8 without hydroxyl groups have also been prepared and evaluated their photoreduction performances in order to validate this hypothesis. The results clearly prove the hydroxyl groups tend to enhance CO 2 photoreduction. Additionally, it is noted that TpPa/ZIF-8 could maintain certain photocatalytic activity under the irradiation of sunlight. Summarily, the superior photocatalytic performances of TpPa/ZIF-8 may result from the high charge separation efficiency and increased photocatalytic active sites as well as the CO 2 adsorption capacity. The reported work sheds light on the construction of MOFs/COFs hybrid materials and expands their applications. [ABSTRACT FROM AUTHOR]