Facile synthesis of bismuth(III) based metal-organic framework with difference ligands using microwave irradiation method

In this study, we studied the effect of starting ligands such as 1,4-benzenetdicarboxylic (H2BDC), 1,3,5-benzenetricarboxylic (H3BTC), and 4,4',4-s-triazine-2,4,6-triyl-tribenzoic (H(3)TATB) acids on the photocatalytic activity of three bismuth-based MOFs (Bi-MOF) obtained via a microwave-assisted solvothermal process. Different shapes and sizes of ligands displayed different structure properties from the corresponding Bi-MOF. Specifically, Bi-MOF composed of Bi3+ and H(3)TATB (Bi-TATB) exhibits the largest specific surface area of 355 m(2)/g, highest surface-oxygen vacancy amount, a more vigorous light absorption intensity with a broader range of visible light absorption and red-shifted absorption edge than that of Bi-MOF composed of Bi3+ and H2BDC (Bi-BDC) and Bi-MOF composed of Bi3+ and H3BTC (Bi-BTC), suggesting the extension in the photocatalytic activity for Bi-TATB. The reason is attributed to the difference in their structural features. Compared with H2BDC and H3BTC ligands in Bi-BDC and Bi-BTC, H(3)TATB ligands in the structure of Bi-TATB contained more delocalized Tr electrons. This outcome may facilitate the ligand-to-metal charge transfer (LMCT) and decrease the electronic bandgap of the Bi-TATB, thus contributing to the enhanced photocatalytic rate. The enhanced photocatalytic activity of Bi-TATB was further confirmed by the photodegradation of rhodamine B (RhB) under LED light irradiation, which is 99.1% of RhB removal after 180 min of light irradiation. The as-synthesized Bi-TATB showed promising photocatalytic activity for the degradation of organic dye with an excellent recyclable catalytic efficiency. With the above understanding, Bi-MOF was finally used for the photocatalytic O-2 evolution from water under LED light irradiation. The Bi-TATB had a maximum photocatalytic O-2 evolution rate of 691 mu mol h(-1). To the best of the author's knowledge, there has been no research on both the photocatalytic degradation of organic model dye pollutants and photocatalytic O-2 evolution studies using Bi-MOFs with different organic linkers. The results should open an alternative approach of ligand selection that could increase the applicability of Bi-MOF in the field of catalysis. (C) 2021 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.

Automated summary

This study investigated the impact of different starting ligands on the structure and photocatalytic activity of Bi-MOFs, with Bi-TATB demonstrating the best photocatalytic performance due to its unique structural features.