3D WO3/BiMOF/Bi2WO6 with rich vacancies defects self-assembled via H2BDC anchoring Bi source of Bi2WO6 for high-performance visible light-driven nitrogen fixation and organic pollutant degradation

A novel photocatalyst WO 3 /BiMOF/Bi 2 WO 6 was prepared by self-assembly of benzene dicarboxylic acid ligand (H 2 BDC) anchoring Bi source on the surface of Bi 2 WO 6 to form BiMOF, in which WO 3 spherical particles were scattered uniformly. Thereby, an amount of metal and oxygen vacancies (V M + O ) are generated. The 3D flower-like spherical photocatalyst has a large specific surface area and close interfacial contacts, which can provide sufficient channels for carrier migration. The introduction of BiMOF enhanced the light absorption capability of photocatalyst. As a result, the flower-like WO 3 /BiMOF/Bi 2 WO 6 structure exhibits excellent nitrogen fixation as well as high-level photocatalytic activity in degrading Rhodamine B (RhB) and tetracycline (TC) under visible light. For one thing, WO 3 /BiMOF/Bi 2 WO 6 produce ammonia up to 227 μmol L −1  h −1 . For another, the degradation efficacy displayed by RhB 99.3% in 15 min and TC 93.6% degradation in 50 min, respectively. In addition, the catalysts showed excellent cyclic stability, with constant degradation efficiencies for at least 4 cycles. The experimental results of free radical scavenging showed that holes (h + ) and superoxide radical (·O 2− ) were the main active substances in the photodegradation process. Therefore, the photocatalytic mechanism of 3D flower-like WO 3 /BiMOF/Bi 2 WO 6 was also proposed.