Synthesis Of Ag₂CO₃-based Composites And Study On Their Visible-light Photocatalytic Performance

Organic pollutants and harmful bacteria in water can be removed by photocatalytic technology using sunlight with solid photocatalysts.Because of its excellent purification ability,photocatalytic technology will be considered as a green chemical technology for the treatment of water pollutants in the future.Ag₂CO₃semiconductor materials have excellent chemical properties of the visible light response but its photocorrosivity make it difficult to widespread used.In this paper,a series of Ag₂CO₃ composite photocatalysts were prepared to improve the photocatalytive activity.The photocatalytic activity was evaluated by the degradation of organic pollutants.The main research contents are as follows:1.A series of SrCO₃-Ag₂CO₃ composite photocatalysts with different SrCO₃molar fractions were prepared by a stepwise precipitation method.It was found that the combination of SrCO₃ enhanced the light absorption capacity of Ag₂CO₃ in the visible light region and widen the light response range.Moreover,the resistance of photo-generated carriers transference was reduced and the efficiency of photo-generated carrier separation and utilization was improved.The photocatalytic activity of Ag₂CO₃ was greatly improved.Among them,the S-A-3 sample（the mole fraction of SrCO₃ was 17.5%）showed the best photocatalytic activity and the degradation rate on acid orange II and methyl orange were increased by 20%and 45%than pure Ag₂CO₃,respectively.2.A series of SrCO₃-Ag₂CO₃ composite photocatalysts with different molar ratios were prepared by gas phase co-precipitation method using greenhouse gases CO₂ as carbon source.The photocatalytic activity of the pure Ag₂CO₃ sample prepared by this method was relatively poor.With the addition of SrCO₃,the photocatalytic activity was significantly improved.From the characterization results,it can be seen that the particle size of the Ag₂CO₃ was large.After compositing SrCO₃,the morphology of the composite photocatalysts was changed and the specific surface area was increased,which was beneficial to the separation of photogenerated electron-hole pairs.At the same time,the absorption of visible light was enhanced and the photocatalytic activity was improved.3.MoS₂ layered semiconductor material was prepared by the hydrothermal method and a series of MoS₂-Ag₂CO₃ composite semiconductor photocatalysts with different mass fractions were prepared by precipitation route.Due to the excellent photoelectric properties of MoS₂,the photo-generated carrier migration efficiency of the composite material was significantly improved and it led to a better photocatalytic activity.Among them,the 15%MoS₂-Ag₂CO₃ showed the best photocatalytic activity and the degradation rate on acid orange II and phenol were increased by 31%and44%than pure Ag₂CO₃,respectively.