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 WO3/BiMOF/Bi2WO6 was prepared by self-assembly of benzene dicarboxylic acid ligand (H2BDC) anchoring Bi source on the surface of Bi2WO6 to form BiMOF, in which WO3 spherical particles were scattered uniformly. Thereby, an amount of metal and oxygen vacancies (VM + 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 WO3/BiMOF/Bi2WO6 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, WO3/BiMOF/Bi2WO6 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 (·O2−) were the main active substances in the photodegradation process. Therefore, the photocatalytic mechanism of 3D flower-like WO3/BiMOF/Bi2WO6 was also proposed.