扩渗温度对TiO_2 NTs/TC4光催化制氢性能的影响

Effects of Thermal Penetration Temperature on Photocatalytic Hydrogen Producing Performance of TiO_2 NTs/TC4

为了提高TiO_2薄膜光催化活性,采用阳极氧化在TC4钛合金表面制备了TiO_2纳米管阵列。利用扫描电镜、X-射线衍射、拉曼谱图、X-射线光电子能谱和紫外可见漫反射光吸收对热扩渗后的阳极化膜层的微观结构进行表征。结果表明：在TC4钛合金的α和β相,氧化膜呈不同的形貌,α相区域纳米管的孔径约为50 nm,β相区域只形成了不规则、大小不均的1~10 nm的小孔。氧化物中V离子的存在对锐钛矿相的生成具有抑制作用,扩渗θ在500和600℃时,膜层中存在少量结晶度不高锐钛矿与金红石相并存的晶体结构。吸附在阳极化膜层表面的碳化物含有石墨相,碳修饰TiO_2纳米管列在可见光区域有很强的光响应区间。在600℃扩渗温度下得到的具有部分石墨化的C修饰V掺杂的TiO_2NTs光催化活性最高,膜层产氢速率为21.25μmol/h。

In order to improve the photocatalytie activity of TiO2 thin film, TiO2 nanotube arrays were pre- pared on TC4 alloy surface by anodic oxidation. The microstructure of the anodized film layer after thermal penetration was characterized by means of SEM, XRD, Raman, XPS and UV-Vis diffuse reflection spec- troscopy. The results showed that the morphologies of anodized films were different in α phase andβ phase of TC4 alloy,in αphase region the pore diameter of TiO2 nanotube was approximately 50 nm, in phase region only several irregular nanopores of 1 - 10 nm diameters were formed. The presence of V ions in oxide could inhibit the generation of anatase phase, when thermal penetration temperature was 500℃ and 600℃, a small amount of low erystallinity anatase and rutile phase coexisting crystal structure was ex- isted in the film layer. The carbide adsorbed on the anodized layer surface contained graphite phase, the carbon modified TiO2 nanotubes had a strong light response range in visible light region. The partly graph- itized, carbon modified and V-doped TiO2 NTS, obtained under 600 ℃, revealed the highest photoeatalytic activity, and the hydrogen producing rate of the film layer was 21.25μmol/h.