The Preparation, Characterization And Properties Of Bismuth-Based Heterostructures Photocatalyst

Photocatalytic technology has great potential in solving environmental pollution.TiO₂ is the most representative material that has been restricted in the practical application of research due to its large band gap and low quantum efficiency. As the band gap is narrow, bismuth compounds exhibit good light absorption and good photocatalytic activity in the scope of visible light.（BiO）₂CO₃ is a novel bismuth-based semiconductor photocatalytic material with a typical ―sillén‖ phase. The hybrid orbital of Bi6s and O2p form a continous valence band on the orginal valence band position, which could reduce the band gap and has absorption in the visible light. Moreover,（BiO）²⁺ layer and CO3^2- layer are arranged alternately,which is beneficial to phtot-generated carriers transport.Therefore,（BiO）₂CO₃ has a wider application prospect in the field of photocatalysis. This article explores the effective way of（BiO）₂CO₃ in increasing the visible light photocatalytic activity by the study of hygrothermal synthesis doping and heterostructures construction.The main study contents are as follows:（1） The flakes（BiO）₂CO₃were fabricated via hydrothermal method with Bi（NO₃）·5H₂O and Na₂CO₃ as raw materials. The best preparation conditions of（BiO）₂CO₃ had been obtained by changing hydrothermal time, hydrothermal temperature and the p H of reaction solution. The research indicaed that（BiO）₂CO₃ has the best photocatalytic activity under simulated sunlight source when hydrothermal temperature was 140 ℃, hydrothermal time was 2 h and p H was 9.9 as well as the degradation rate of reactive brilliant blue（KN-R） was 86.1 %.（2） The S-doped Bi₂S₃/（BiO）₂CO₃ heterostructure composite photocatalyst were fabricated via a simple liquid-phase sulfurization method with thioacetamide （TAA） as S source. It had studied the effect of the different molar ratio between S and Bi on the morphology and photocatalytic activity of composite photocatalyst. And the obtained products are analyzed by a variety of detection methods. The research indicated that the best photocatalytic activity of the flakes composite photocatalyst can be achieved under simulated sunlight source when the molar ratio between S and Bi was 0.15, the degradation rate of KN-R was 95 %.（3） The N-doped Bi₂S₃/（BiO）₂CO₃ heterostructure composite photocatalyst were fabricated via hydrothermal method with L-cysteine as raw materials.It had studied the effect of the different dosage of L-cysteine on the morphology and photocatalytic activity of composite photocatalyst. And the obtained products were analyzed by a variety of detection methods. The research indicates that the composite photocatalyst were flakes when the dosage of L-cysteine was less than 0.6 mmol, but when was equal to or greater than 0.6 mmol, the rose-like composite catalyst appeared. The highest photocatalytic activity of the composite photocatalyst can be achieved under simulated sunlight source when the dosage of L-cysteine is 0.6 mmol, the degradation rate of KN-R was 98.4 %（4） The Bi₂ MoO₆/（BiO）₂CO₃ heterostructure composite photocatalyst were fabricated via hydrothermal method with ammonium molybdate as raw materials. It has studied the effect of the different molar ratio between Mo and Bi on the morphology and photocatalytic activity of composite photocatalyst. And the obtained products were analyzed by a variety of detection methods. With the increase of Mo, the composite catalyst nano-chip crystal grew along the{001}plane, the thickness of the nanosheets increase gradually. It had excellent photocatalytic performance under simulated sunlight source while the molar ratio between Mo and Bi was 0.14, the degradation rate of KN-R was 91 %.