Synthesis Of Mesoporous G-C₃N₄ Composites And Their Catalytic Properties Under Visible Light Irradiation

Mesoporous materials have attracted more attentions because of their larger specific surface area and more active sites.The reactants pass through the pores in the mesoporous materials and contact with the enlarged active sites,improving the efficiency of the catalytic reaction,which makes the mesoporous materials are employed in a great amount of catalytic reactions.However,for some large-scaled molecular reactions,the pore size of mesoporous materials is clearly insufficient to achieve mass transfer requirements.At the same time,in the field of photocatalytic applications,it is urgent to find stable,cheap,facile,green and efficient visible light catalysts for energy utilization efficiency and environmental protection.In order to synthesize visible light response catalysts that achieve the advantages above mentioned,and overcome the limitation of large molecular.In this paper,large-scaled mesoporous g-C₃N₄/TiO2 photo-catalysts with heterostructure whose pore size exceed 30 nm were synthesized via a simple hard template method using titanium butoxide and dicyandiamide as the raw materials at room temperature.We also investigated the catalytic performance of the catalysts at different calcination temperatures and different g-C₃N₄ mass percentage at the same temperature in the preparation process.The photocatalytic ability of the as-prepared samples was tested by degradation of RhB solution at room temperature under visible light irradiation.XRD,FT-IR,XPS,PL,nitrogen adsorption/desorption,electrochemical measurements,SEM and TEM characterization results showed that the g-C₃N₄ content in precursor played an important role when the calcination temperature was identified.At the optimal loading content of g-C₃N₄,the degradation rate of RhB solution can reach 99% at 60 min obviously higher than that of mesoporous g-C₃N₄ and pure TiO2.The enhancement of photocatalytic activity of g-C₃N₄/TiO2 can be attributed to its larger specific surface area,more suitable pore size and existent of heterostructure.PL,electrochemical measurements and HRTEM results showed that the heterojunction which is good for charge separation and transfer has been successfully synthesized.In addition,we have prepared mesoporous g-C₃N₄/ZnO photo-catalysts with heterostructure using zinc chloride and dicyandiamide as raw materials by a similar synthesis method to g-C₃N₄/TiO2.The effect of the component content on the catalytic activity of the catalyst was investigated.The catalyst gave a higher catalytic activity when the mass percentage of g-C₃N₄ in the composite was 20.58%.Through a series of related characterization and analysis,it has proved that we have successfully synthesized the mesoporous g-C₃N₄/ZnO and achieved the desired goal.