| Photocatalytic hydrogen evolution provides a new way for solar energy conversion to produce clean fuel,and it is also one of the effective strategies to achieve the goal of"double carbon".However,due to the high Gibbs free energy(ΔG=237.1 k J mol-1)of water decomposition and the low separation efficiency of electrons and holes,the energy conversion efficiency of hydrogen production by photocatalytic water decomposition is still not high,which is difficult to meet the requirements of industrial application.Semiconductor material is the carrier material of photocatalytic reaction.As a potential semiconductor material,Ti O2 has been favored by scholars because of its low cost,good chemical stability and non-toxicity.However,the weak absorption of visible light and the easy recombination of photogenerated carriers on its surface limit its application in water decomposition.In this paper,Ti O2-xnanotube arrays modified by oxygen vacancies were prepared by anodic oxidation,which extended the absorption performance of Ti O2-x to the visible region.At the same time,by forming heterojunction with cocatalyst,the separation efficiency of photogenerated carriers was improved,and the performance of photocatalytic water decomposition for hydrogen production was enhanced.The specific work is as follows:（1）The photocatalytic hydrogen evolution Zn In2S4/Ti O2-x nanotube arrays with high visible light responsiveness were prepared by two-step method.Due to the introduction of oxygen vacancies and the visible light drive of Zn In2S4,Zn In2S4/Ti O2-x nanotube arrays show light response from ultraviolet to visible light.In addition,heterojunction improves the separation of photogenerated carriers and promotes the transfer of electrons from Zn In2S4 to Ti O2-x,thus prolonging the life of active electrons and enhancing the photocatalytic activity of hydrogen evolution.The yield of H2 is 581.1μmol h-1 g-1,and the apparent quantum yield（AQY）is as high as～1.42%.This work shows that the defect-induced band gap engineering of semiconductor photocatalyst is a potential way to extend the optical absorption characteristics of Ti O2 to visible light or even near infrared,and improve the photocatalytic activity.（2）2D/1D Ti3C2/Ti O2-x composite photocatalyst with visible light response was prepared by anodic oxidation and ultrasonic-assisted impregnation.Ti3C2 has strong electrical conductivity,which enables photogenerated electrons to be quickly transported from Ti O2-x carrier to the reactive center to complete photocatalytic water reduction reaction to generate hydrogen.The photoelectrochemical properties and photocatalytic properties show that Ti3C2/Ti O2-x has excellent carrier separation ability,and the photocatalytic hydrogen production efficiency can reach 818.46μmol h-1g-1,which is 4.2times that of Ti O2-x(193.40μmol h-1g-1),which proves that Ti3C2/Ti O2-x composite photocatalyst has the following characteristics. |
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