One-step preparation (3D/2D/2D) BiVO4/FeVO4@rGO heterojunction composite photocatalyst for the removal of tetracycline and hexavalent chromium ions in water

In promoting the application of green and sustainable chemistry in wastewater treatment, it is urgent to explore effective and stable photocatalysts with excellent degradability on tetracycline (TC) and reduction of Cr (VI). However, photogenerated charge recombination and low visible light utilization limit the application of photocatalysts. To solve this problem, we successfully prepared all solid BiVO4/FeVO4@rGO photocatalyst with novel 3D/2D/2D heterojunction structure prepared via one-step hydrothermal method. The formation of this unique 3D/2D/2D heterojunction leads to the creation of nanochannels in their interfacial contact, improved light-induced charge transport and migration efficiency. The effect of rGO dosages, inorganic anions (SO42-, Cl-, Cr(6+)and CO32-) and organic material on the degradation of tetracycline by BiVO4/FeVO4@rGO photocatalyst was systematically investigated. Results showed that the splendid degradation performance of BiVO4/FeVO4@rGO photocatalyst was ascribed to novel 3D/2D/2D structure with the designated migrated directions of photogenerated charges, suppressed recombination rate of electrons-holes, the large specific surface area, and enhanced transport and separation efficiency of photogenerated carrier. The main active species in photocatalytic oxidation reactions were verified as h(+) and center dot O2- by free radical scavenging tests and electron spin resonance (ESR) analysis. Moreover, the possible degradation process of TC was analyzed with 3D EEMs and LC-MS techniques, then the mechanism of photocatalysis was proposed. Surprisingly, BiVO4/FeVO4@rGO material always exhibited high degradation efficiency of TC in simulation experiments with different water sources, exhibiting an excellent practical application value.