Preparation And Photocatalytic Properties Of Two-dimensional Ti₃C₂ Heterophotocatalyst

In recent years,environmental problems caused by organic wastewater have.become more prominent.These organic wastewater will lead to eutrophication of water bodies and seriously threaten the living environment of human beings.Although traditional treatment methods such as physical adsorption,chemical oxidation,and biodegradation can remove dyes,they are costly and prone to secondary pollution,and the resulting unstable metabolite intermediates will adversely affect human health.Photocatalysis technology uses light energy to generate photo-generated electrons and holes through a suitable photocatalyst,and uses its reduction and oxidation properties to produce hydrogen and oxygen,reduce carbon dioxide to produce organic matter,and can also reduce oxygen to produce superoxide radicals or the oxidation of water molecules generates hydroxyl radicals to degrade pollutants in the environment.As one of the most widely studied semiconductor photocatalysts,TiO2 has good light,excellent chemical stability and environmental friendliness,and has been widely used in environmental remediation,water decomposition,artificial photosynthesis and other fields.The relatively wide band gap and rapid recombination of photogenerated carriers limit its practical applicationsin wastewater treatments.Buliding heterojunctions based on TiO2 have been proved to overcome these limitions.Therefore,the preparation of a heterogenous photocatalystwith high photocatalytic activity have broad development prospects and research significances.In this paper,the g-C3N4 shell was successfully in-situ grown on the TiO2/TiB2 core by a one-step calcination method,and its photocatalytic degradation performance was also evaluated by the removal of RhB.The results show that,the as-obtained TiB2/g-C3N4 photocatalysts show higher photocatalytic activities of rhodamine B(RhB)and 4-chlorophenol(4-CP)compared with pure g-C3N4,.Among them,when the weight ratio of melamine and titanium boride precursor is 100:1,the as-prepared samples shows the highest photocatalytic activity.The free radical capture experiment was also carried out to further investigate the main reactive species for the photocatalytic degradation.The results show that·OH is the main active species in the photocatalytic degradation of RhB.At last,the Z-heterojunction mechanism of this system for photocatalytic degradation is proposed based on these data.In the next chapter,we combined 1-TBCN and 2DTi3C2 MXene by hydrothermal method to obtain a new type of TiB2/g-C3N4@Ti3C2 ternary heterojunction photocatalyst.It is found that the synthesized ternary heterojunction photocatalyst has a certain degree of improvement compared with binary photocatalyst.When the doping amount is 5%wt,the photocatalyst shows the highest removal of RhB.Finally,the photocatalytic mechanism of the ternary system is proposed.