Study Of The Preparation And Photoelectrochemical Performance Of TiO₂ Based Nanomaterials

In recent years,the scientists face two important issuses-energy shortage and environmental pollution.As a clean energy source,hydrogen energy can solve both the energy shortage problem and the environmental pollution problem.At present,the use of photocatalysis/photoelectrocatalysis technology to solve energy crisis and environmental crisis has attracted more and more attention.In this paper,a facile and available TiO₂ nanotube array is used as a substrate,and the TiO₂ nanotube array is optimized and modified to improve its photocatalytic performance.The main research contents are as follows:（1）A simple two-step anodization method was used to prepare the TiO₂ nanotube array directly on the Ti foil.Using vertically grown TiO₂ nanotube arrays as matrix materials,Ti O_2-x nanomaterials were prepared by a simple solution（Na BH₄）reduction method.The electrochemical results show that the value of Ti O_2-x at 1.23 V vs.RHE is0.65 m A?cm^-2,which is 66.67%higher than that of TiO₂ electrode(0.38 m A?cm^-2).The incident photon-current conversion efficiency（IPCE）reaches 58.13%,which is 86.79%higher than that of pure TiO₂.The introduction of oxygen vacancies（V_O）makes the band-gap smaller,promotes the separation of photogenerated electrons and holes.（2）Based on the vertically grown TiO₂ nanotube arrays（NTA）,Ti O_2-x/BP heterojunction photoelectrode for PEC water decomposition was prepared for the first time by using black phosphorus quantum dots（BPQD）and oxygen vacancies（V_O）.The electrochemical results show that the loading of BPQD and the introduction of V_O can reduce the band gap,promotes the separation of photogenerated electrons and holes,and significantly increase the density of photocurrent.The maximum photocurrent density exhibited by the Ti O_2-x/BP photoelectrode at 1.23 V vs.RHE is 1.12 m A?cm^-2,which is almost three times of original TiO₂ electrode(0.38 m A?cm^-2).The results show that the V_O and BPQD in the Ti O_2-x/BP composite not only promote the separation and migration of charges,but also enhance the activity and number of active sites in the water oxidation reaction.（3）Based on the vertically grown TiO₂ nanotube arrays（NTA）,the Zn_0.4Ca_0.6In₂S₄（ZCIS）nanoparticles were loaded by a one-step hydrothermal method.The good light absorption properties of ZCIS nanoparticles and the good separation and transfer of photogenerated electrons and holes after the formation of heterojunctions are utilized.The electrochemical results show that the maximum photocurrent density of the TiO₂/ZCIS photoelectrode is 0.63 m A?cm^-2 at 1.23 V vs.RHE,which is an increase of61.5%compared to pure TiO₂.In addition,the incident photon-current conversion efficiency（IPCE）of TiO₂ and TiO₂/ZCIS at 365 nm increased from 31.03%to 42.29%,respectively.