TiO<sub>2-QDs/Nb<sub>4N<sub>5纳米花的控制合成及太阳光催化全解水析氢性能  

Controllable Synthesis of TiO<sub>2-QDs/Nb<sub>4N<sub>5 Nanoflowers and Its Property for Solar Photocatalytic Overall Water Splitting into Hydrogen

作　　者：庄同林 

机构地区：[1]哈尔滨师范大学化学化工学院,黑龙江 哈尔滨

出　　处：《材料科学》2022年第6期560-567,共8页Material Sciences

摘　　要：本文以NbCl5为前驱体,利用水热技术制备了Ti4+掺杂Nb2O5纳米花,再经高温氮化制得TiO2-QDs/Nb4N5纳米花。考查Ti4+掺杂量、水热时间、氮化温度对样品光生载流子分离效率的影响规律,建立了TiO2-QDs/Nb4N5纳米花的优化工艺,在Ti4+掺杂量1 wt%、水热时间3 h、氮化温度800℃时样品光电流为0.035 μA•cm−2,是Nb4N5纳米花(0.014 μA•cm−2)的2.5倍,载流子分离效率显著提升。在500 W氙灯模拟太阳光照射下,样品光催化全解水产氢活性为109.9 μmol•g−1•h−1,明显高于未修饰的Nb4N5样品(87.9 μmol•g−1•h−1)。2~3 nm TiO2量子点修饰在Nb4N5表面形成TiO2/Nb4N5局域异质结构,增强了从紫外到整个可见光区域的光吸收性能,促进了载流子高效分离,增大了比表面积及2~17 nm微介孔数量,增加了表面催化活性点位,协同提升样品太阳光催化全解水产氢活性。本文为进一步开发高性能Nb4N5基纳米光催化材料奠定了实验技术基础。TiO2-QDs/Nb4N5 nanoflowers were obtained by high-temperature nitriding Ti4+-doped Nb2O5 nanoflowers prepared by hydrothermal synthesis method, using NbCl5 as a precursor. Based on the effects of Ti4+-doping amount, hydrothermal time, and nitriding temperature on the separation efficiency of photogenerated carriers, an optimized process for TiO2/Nb4N5 nanoflowers was constructed. When the condition of Ti4+-doping amount was 1 wt%, and the hydrothermal time was 3 h, and the nitridation temperature was 800˚C, the photocurrent density of the sample reached to 0.035 μA•cm−2, which was 2.5 times that of Nb4N5 nanoflowers (0.014 μA•cm−2). The separation efficiency of charged carriers was improved significantly. Under simulated sunlight irradiation of 500 W Xenon lamp, the photocatalytic overall water splitting into hydrogen activity of TiO2/Nb4N5 was 109.9 μmol•g−1•h−1, significantly higher than that of the unmodified Nb4N5 sample (87.9 μmol•g−1•h−1). 2~3 nm TiO2-QDs modification formed TiO2/Nb4N5 local hetero-structures, which enhanced the light absorption capability from UV to entire visible region, promoted the efficient separation of charged carriers, and increased the specific surface area and micro-mesopores of 2~17 nm. The surface catalytic active sites were increased. All the above factors led to an enhanced photocatalytic activity for overall water-splitting into hydrogen under simulated sunlight irradiation. This work lays an experimental technical foundation for further developing high-performance Nb4N5-based nanophotocatalysts.

关 键 词：Nb< sub> 4N< sub> 5 TiO< sub> 2量子点 异质结 太阳光催化 全解水产氢 

分 类 号：O644.1[理学—物理化学]