【作者】 陈瑶；

【导师】 罗胜联；

【作者基本信息】 湖南大学 ， 分析化学， 2013， 硕士

【摘要】 作为一种n型宽带隙无机半导体材料，二氧化钛纳米管阵列（TiO₂NTs）具有高比表面积、高度有序和可重复利用的特性，在光催化研究中备受关注。然而，受到TiO₂NTs带隙宽、光生电子-空穴复合率高、对水体中的有机污染物吸附能力弱等缺点的制约，TiO₂NTs的实际应用效果不甚理想。目前，大量的研究报道表明，对TiO₂NTs进行离子掺杂、贵金属沉积和半导体修饰等方法可以提高材料对可见光的吸收和光催化效率。本论文采用电化学阳极氧化法制备TiO₂NTs，采用半导体修饰拓宽了TiO₂对可见光的吸收、提高其光电分离效率并降低光电复合效率、利用金属和石墨烯的复合修饰增强TiO₂对有机物的吸附，最终提高光催化降解效率和稳定性，实现了材料的可回收利用。具体研究内容如下：（1）Ag₂O/TiO₂纳米管阵列（Ag₂O/TiO₂NTs）复合材料的制备、表征和光催化性能研究：首先应用脉冲电沉积技术在已晶化的TiO₂NTs的顶部和内部沉积纳米银单质颗粒，然后在氢氧化钠溶液中对Ag/TiO₂NTs电极进行电氧化，得到超细的Ag₂O纳米线网状结构修饰的复合纳米管光催化材料。结果表明，该复合材料可吸收可见光，Ag₂O纳米线彼此连接构成通达的网状结构，提高了光生载流子的运输效率，因而模拟太阳光照下能有效降解模拟废水溶液中的酸性橙7（AO7）。（2）Zn_xCd_1-xS/TiO₂纳米管阵列(Zn_xCd_1-xS/TiO₂NTs)复合材料的制备、表征和光催化性能研究：通过循环伏安电沉积的方法制备出了Zn_xCd_1-xS纳米颗粒修饰的TiO₂NTs复合材料，并研究了不同Zn/Cd比对光催化性能的影响。相比于TiO₂NTs， Zn_xCd_1-xS/TiO₂NTs具有更显著的可见光吸收和光催化性能。另外，当Zn/Cd=1/3时，该复合材料对模拟水溶液中的亚甲基蓝（MB）光催化降解效率最高，相对CdS修饰的TiO₂NTs复合材料，稳定性也得到大大提高。（3）Au/RGO/TiO₂纳米管阵列（Au/RGO/TiO₂NTs）复合材料的制备、表征及光催化性能研究：通过一种简单的一步恒电位沉积的方法制备Au/RGO/TiO₂NTs复合材料，和纳米Au颗粒修饰TiO₂NTs（Au/TiO₂NTs）,电沉积还原修饰的石墨烯（RGO/TiO₂NTs）和未修饰的TiO₂NTs相比, Au/RGO/TiO₂NTs复合材料在模拟太阳光照射下对甲基橙（MO）的降解效率高达100%。结果显示，纳米金颗粒和石墨烯薄膜的修饰不但提高了复合材料的光催化性能，同时也提高了复合材料的稳定性，实现了材料的重复利用。更多还原

【Abstract】 As an n-type semiconductor material, titanium dioxide （TiO₂） is widelyconcerned in photocatalytic application because of its chemieal stabil ity, highcatalytic efficiency, nontoxicity, and low cost. However, the practical application ofTiO₂is retarded by its wide band gap, high recombination rate of the photogeneratedelectron-hole pairs, poor adsorbability to most of organic contaminants, poorabsorption and poor recovery. Nowdays, many researchers have been developed somemethods to solve the problems, such as ion doping, noble metal deposition andsemiconductor combination.TiO₂nanotube arrays prepared by electrochemical anodic oxidation weremodified with noble metal, semiconductor or composite based on graphene to extendthe absorption of TiO₂to the visible spectrum region, improve the separationeffeciecy of photogenerated carriers, achieve the recycle, enhance the adsorptivity toorganic pollutants, or increase photocatalytic efficiency. The main research contentsare listed below:（1） Fabrication, characterization and photocatalystic application of Ag₂O/TiO₂NTs: Ag/TiO₂NTs were prepared through a pulsed electrodepositon method, and thenthe Ag/TiO₂NTs were potentio-statically anodized in0.5M NaOH electrolyte at0.5Vfor30min at25°C to fabricate Ag₂O nano-network on TiO₂NTs. Compared with bareTiO₂NTs, the resulting photocatalyst showed stronger absorption in visible spectrumregion and exhibited higher photocatalytic degradation efficiency of AO7under thesimulated solar light.（2） Fabrication, characterization and photocatalystic application ofZn_xCd_1-xS/TiO₂NTs: Zn_xCd_1-xS was fabricated on the surface of TiO₂NTs by one-stepcyclic voltammetry electrodeposition technique. It was also studied the effect ofdifferent Zn/Cd ratio on the degradation efficiency of methylene blue （MB）.Compared with the unmodified TiO₂NTs, Zn_xCd_1-xS/TiO₂NTs showed the strongerabsorption in visible spectrum region and exhibited higher photocatalytic degradationefficiency. When the Zn/Cd ratio is1/3, MB degradation efficiency ofZn0.25Cd0.75S/TiO₂NTs is the highest. Moreover, compared with CdS modified TiO₂NTs, Zn_xCd_1-xS/TiO₂NTs are much more stable.（3） Fabrication, characterization and photocatalystic application of Au/RGO/TiO₂NTs: Au nanoparticles and reduced graphene oxide co-decorated TiO₂nanotube arrays （Au/RGO/TiO₂NTs） were prepared through a simple one-stepconstant-potential electrolysis of chloroauric acid and graphene oxide on TiO₂NTs.Compared with Au/TiO₂NTs, RGO/TiO₂NTs and un-modified TiO₂NTs, theAu/RGO/TiO₂NTs exhibited the highest efficiency （nearly100%） in photocatalyticdegradation of methyl orange （MO） under simulated solar light irradiation. The highlyefficient photocatalytic activity is associated with broad absorption in the visible lightregion, increased photoinduced charge separation through transferring photogeneratedelectrons from TiO₂NTs to both Au and RGO, as well as the strong adsorption abilityof RGO to MO molecules. Moreover, the Au/RGO/TiO₂NTs has an excellent stability.更多还原