Construction Of A Photocatalytic System Containing Ti₃V₂ MXene And Its Photocatalytic Performance

Nowadays,photocatalytic technology has been developed in many fields,such as photocatalytic decomposition of water and hydrogen evolution,photocatalytic degradation of pollutants and photocatalytic reduction of carbon dioxide.Through the development of photocatalysis technology,it is expected to solve the problems of energy shortage and environmental pollution.Finding efficient and stable photocatalysts is the key to develop this technology.Therefore,in this paper,we take Ti₃C₂ MXene nano-materials as the core,construct a series of photocatalysis systems composed of Ti₃C₂ MXene,and investigate their applications in photocatalytic hydrogen production and photocatalytic degradation of organic pollutants.The main research contents and results are as follows:First,the Ti₃C₂/Zn WO₄ photocatalytic system was constructed by the synergistic interaction between Ti₃C₂ MXene nanosheets and tungstate nanocubes.On this basis,the photocatalytic behavior and influencing factors of malachite green degradation were investigated.The results show that Ti₃C₂/Zn WO₄ photocatalytic system has very high photocatalytic activity for malachite green degradation.When Ti₃C₂/Zn WO₄ photocatalytic system was used as catalyst,the removal rate of 20 mg L^-1 of malachite green could reach99.0%after 90 min of illumination under the optimal conditions.Through research,we found that its excellent photocatalytic performance is attributed to the heterojunction formed between Ti₃C₂ nanosheets and Zn WO₄ nanocubes,which is conducive to the efficient separation of electron-hole pairs.Secondly,we constructed a photocatalytic system consisting of Ti O₂ nanosheets and Cu WO₄ nanoparticles embedded with Ti₃C₂ MXene quantum dots.At the same time,the photocatalytic hydrogen production behavior of the obtained material was discussed.We found that the photocatalytic system is an efficient photocatalyst for hydrogen production without precious metals.Under its catalytic action,the fastest hydrogen evolution rate of the system can reach 3.65 mmol g^-1 h^-1.This activity is 192 times that of titanium dioxide nanoparticles（P25）.In addition,the photocatalytic system has good stability.After 9 cycles,it can even show stronger photocatalytic activity than the unused photocatalyst.It can be seen that Ti O₂ nanosheets embedded with Ti₃C₂ quantum dots have great potential as a photocatalytic platform.We speculate that Ti₃C₂ quantum dots play the role of active center and electron transport channel in this photocatalytic process.The high efficiency and stable photocatalytic hydrogen production activity of the photocatalytic system may be mainly from the S-scheme heterojunction formed between Ti O₂ nanoparticle and Cu WO₄ nanoparticle.Finally,a Ti₃C₂/SrWO₄/CdS ternary photocatalytic hydrogen production system was constructed by coupling Ti₃C₂ MXene nanoparticle with SrWO₄ and CdS.At the same time,the photocatalytic performance of hydrogen production was evaluated.The results show that the above photocatalytic system is an efficient and stable CdS-based photocatalytic hydrogen production catalyst.Under its catalytic action,the maximum hydrogen evolution rate of the system can reach 2.44 mmol g^-1 h^-1,and can continue stable hydrogen evolution for 15 h.This is due to the heterojunction formed between SrWO₄ and CdS.Under its action,the photogenerated electron-hole pairs are effectively separated,and the photocorrosion of CdS is also inhibited to a certain extent.In this system,the main function of Ti₃C₂ nanocrystals is to act as a charge transport channel.In conclusion,we found that Ti₃C₂ MXene nanomaterial is a co-catalyst with excellent performance and can be used in a wide range of photocatalytic systems.This provides a reference value for the subsequent application of Ti₃C₂ MXene nanomaterials in photocatalysis.