Ag/TiO_(2-x)N_x纳米管的光电催化性能

在0.5wt%NaF+1mol/L Na2SO4溶液中,20V电压下,通过阳极氧化的方法,在纯Ti片表面制备出与基底垂直、排列整齐有序的TiO2纳米管,将制得的TiO2纳米管在500℃、氨气的气氛下退火2h,然后,在0.5mol/L AgNO3溶液中用12W的紫外灯照射24h,制备出Ag/TiO2-xNx纳米管,并用XRD,SEM和XPS进行表征.实验结果显示,在紫外光下,Ag/TiO2-xNx纳米管的光电催化降解效率比TiO2纳米管的光电催化降解效率提高了39.68%;在可见光下,Ag/TiO2-xNx纳米管的光电催化降解效率比TiO2-xNx纳米管可见光光电催化的降解效率提高了12%.可见光光电催化16h后,初始浓度为10×10-6mol/L的亚甲基蓝降解率达到50.53%.     

硅掺杂TiO2纳米管阵列的制备及光电催化活性的研究

通过电化学沉积,在阳极氧化法制备的高度有序TiO2纳米管阵列表面均匀地沉积Si元素.扫描电子显微照片显示Si掺杂的TiO2纳米管垂直于基底定向生长.X射线衍射分析表明,所引入的Si可能掺入到TiO2的晶格中,因而提高了TiO2的热稳定性,抑制了金红石相的生成及晶粒的长大.紫外-可见漫反射分析表明Si掺杂的TiO2纳米管吸收边带发生了明显的蓝移,并且在紫外区的吸收强度明显增强.与未掺杂的TiO2纳米管相比,Si掺杂TiO2纳米管电极的紫外光电化学响应显著提高,其光电流密度是未掺杂的1.48倍.硅掺杂TiO2纳米管阵列光电催化降解五氯酚的动力学常数(1.651h-1)是未掺杂TiO2纳米管电极(0.823h-1)的2.0倍.     

Preparation of rGO/AgCl QDs and its enhanced photoelectrocatalytic performance for the degradation of Tetracycline

A novel rGO/AgCl QDs composites have been obtained by an ultrasonic-assisted method for the first time. Photoelectrocatalytic (PEC) performances of the obtained samples were studied by the degradation of 20 mg/L Tetracycline (TC) under visible light irradiation with an applied bias potential of 1.5 V (vs Ag/AgCl). Degradation of TC by different processes including Photocatalysis (PC), Electrocatalysis (EC), and PEC was compared, and the effect of different bias potential on the PEC degradation of TC was discussed. Results showed that rGO/AgCl QDs composites had displayed superior PEC activity than that of pristine AgCl QDs with degrading 85.2% of TC during 120 minutes, which was about 1.5 times higher than that of AgCl QDs (33%). Besides, compared to PC and EC removal of TC, PEC process showed the highest degradation efficiency of TC (85.2%) by rGO/AgCl QDs, which was about three times and one time higher than that of PC (39.18%) and EC (20.73%) system, respectively. Moreover, the reusibility and stability of the samples were tested by five times cycling tests, and results demonstrated that the stability of bare AgCl QDs was improved after the introduction of rGO. The enhanced PEC activity and stability of the samples could be attributed to the intimate contact between rGO and AgCl QDs and external electric field, which had benefitted the formation of more active sites and accelerated electron-hole separation.     

悬浮TiO2-Ti电极体系中光电催化降解甲基橙

研究了在不同浓度的NaCl电解质溶液中,悬浮TiO2-钛电极体系的光电催化降解效率。当降解时间达到60min时,单独光催化降解甲基橙的降解率为50．7％;在10V电压下进行光电催化反应,以0．5mol／LNaCl为电解质时,可使甲基橙降解率达到98．9％。光电催化法对甲基橙的降解率明显高于光催化法和电降解法,电降解和光催化降解之间存在着协同效应,且降解效率随着外加电压和NaCl溶液浓度的增大而提高．     

Photocatalytic and Photoelectrocatalytic Performance of 1% Pt Doped TiO2 for the Detoxification of Water

The degradation of formic acid (HCOOH), FA (a surrogate contaminant) using titanium dioxide (TiO₂) and 1% Pt doped TiO₂ electrodes, prepared by sol—gel methods, was investigated in a photoelectrocatalytic (PEC) system in order to determine the effect of Pt doping on the oxidation potential of TiO₂. Pt doping shifts the position of band edge and therefore the direct and indirect oxidation potentials of TiO₂ in PEC systems. As a result, the degradation of formic acid via the generation of hydrogen peroxide production on 1%Pt—TiO₂ electrodes was much better than that on non-doped electrodes. The degradation of HCOOH was also examined with respect to the faradaic efficiency of this process. It was found that the 1%Pt—TiO₂ photoanode had a 30% higher efficiency than that of non-doped TiO₂ photoanodes.     

负载型二氧化钛光电催化降解苯酚废水的反应动力学

采用浸渍提拉法制备发泡镍载二氧化钛薄膜电极,并以其为工作电极,建立三电极光电催化体系,对该体系降解苯酚的动力学进行了研究.考察了反应液初始pH值、反应物初始浓度、催化剂用量、光辐照强度、外加直流偏压值对光电催化反应速率的影响,采用幂指数方程描述反应动力学,得到方程C=C₀exp(-0.5430 C ^-0.4241 ₀ E ^0.2968 Q ^0.5418 I ^0.5877 t).方程计算值与实验值吻合较好,误差基本在15％以内.     

TiO2纳米管的制备及其在化学需氧量测定中的应用研究

在纯钛表面采用电化学阳极氧化法制备有序的高密度TiO2纳米管阵列，对TiO2纳米管进行X射线衍射（XRD）和扫描电子显微镜（SEM）表征，结果表明氧化钛纳米管膜层的相结构与热处理有关，经500℃热处理后具有光催化活性的锐钛矿型。将其用于化学需氧量（COD）的测定，以葡萄糖为响应底物，考察了TiO2纳米管光电催化传感器的光电催化行为，结果发现该传感器的光生电流值与20～800mg／L范围的COD值有良好的线性响应，检测限为10mg／L，相关系数为0．9977。利用该传感器测定废水样品的COD值，结果与传统的K2Cr207法相吻合。用TiO2纳米管制备的传感器具有测试速度快，不需有毒、昂贵试剂等优点，具有广阔的应用前景。     

铈掺杂TiO2/Ti光电极制备及可见光下光电催化性能的研究

采用阳极氧化法制备铈掺杂TiO2／Ti光电极，用SEM、XRD、XRF、XPS和UV／VIS／NIR对光电极的性能进行表征，并对其可见光照射下的光电催化性能进行了测试．研究结果表明：在成膜电压为160V，电流密度为100mA／cm^2，Ce（NO3）3浓度为960mg／L条件下制备的铈掺杂TiO2／Ti光电极在降解罗丹明B的实验中表现出良好的光电催化活性．     

氮掺杂TiO2纳米管电极制备及可见光电催化活性

采用氮气中500℃和600℃热处理由阳极氧化法制备的TiO2纳米管阵列,制备了氮掺杂TiO2纳米管阵列电极.分别用环境扫描电镜(ESEM)、X射线光电子能谱(XPS),X射线衍射(XRD)和紫外可见漫反射吸收光谱对电极进行了表征.结果表明氮成功地掺入TiO2纳米管中.氮的引入使所制备的电极表现出可见光电催化活性,其中氮气中500℃下热处理得到的TiO2纳米管阵列电极表现出最好的可见光电催化活性.     

两步阳极氧化制备TiO2纳米管的光电催化产氢性能研究

利用两步电化学阳极氧化法制备了TiO2纳米管(TNT),并比较了其与一步阳极氧化法制备的TNT形貌特征和光电催化活性。结果表明:两步氧化法制得的TNT较一步阳极氧化法制得的TNT形貌有较大的差异,两步氧化后TNT平均管长和管径略有增加,分别达到7.67μm和72.12 nm,而管壁厚度则减少到16.36 nm,这导致长径比从59.73显著增加到104.83。相应地,其光-氢转化效率也从0.14%显著增加到0.36%。而目标污染物乙二醇的存在进一步提升了TNT的光电催化降解污染物同时产氢的活性。因此,两步阳极氧化法是一种简单有效改善TNT结构特征和光电催化性能的有效方法,在光电催化降解污水中的有机污染物同时产氢方面有应用前景。