Centre for Advanced Optoelectronic Functional Materials Research, Key Laboratory for UV-Emitting Materials and Technology of Ministry of Education, Northeast Normal University, 5268 Renmin Street, Changchun 130024, People's Republic of China.
J Colloid Interface Sci. 2011 Nov 1;363(1):157-64. doi: 10.1016/j.jcis.2011.07.035. Epub 2011 Jul 21.
A water-dichloromethane interface-assisted hydrothermal method was employed to grow rutile TiO(2) nanowires (NWs) on electrospun anatase TiO(2) nanofibers (NFs), using highly reactive TiCl(4) as precursor. The water-dichloromethane interface inhibited the formation of rutile NWs in water phase, but promoted the selective radial growth of densely packed rutile NWs on anatase NFs to form a branched heterojunction. The density and length of rutile NWs could be readily controlled by varying reaction parameters. A formation mechanism for the branched heterojunction was proposed which involved (1) the entrapment of rutile precursor nanoparticles at water-dichloromethane interface, (2) the growth of rutile NWs on anatase NFs via Ostwald ripening through the scavengering of interface-entrapped rutile nanoparticles. The heterojunction formed at anatase NF and rutile NW enhanced the charge separation of both under ultraviolet excitation, as evidenced by photoluminescence and surface photovoltage spectra. The branched TiO(2) heterostructures showed higher photocatalytic activity in degradation of rodamine B dye solution than anatase NFs, and the mixture of anatase NFs, and P25 powders, which was discussed in terms of the synergistic effect of enhanced charge separation by anatase-rutile heterojunction, high activity of rutile NWs, and increased specific area of branched heterostructures.
采用水-二氯甲烷界面辅助水热法，以高反应性 TiCl 4 为前驱体，在静电纺丝的锐钛矿 TiO 2 纳米纤维（NFs）上生长金红石 TiO 2 纳米线（NWs）。水-二氯甲烷界面抑制了在水相中金红石 NWs 的形成，但促进了在锐钛矿 NFs 上密集堆积的金红石 NWs 的选择性径向生长，形成了分支异质结。通过改变反应参数，可以很容易地控制金红石 NWs 的密度和长度。提出了一种形成分支异质结的机制，该机制涉及（1）金红石前驱体纳米颗粒在水-二氯甲烷界面的捕获，（2）通过界面捕获的金红石纳米颗粒的清除，通过奥斯特瓦尔德熟化在锐钛矿 NFs 上生长金红石 NWs。在紫外光激发下，形成在锐钛矿 NF 和金红石 NW 之间的异质结增强了两者的电荷分离，这可以通过光致发光和表面光电压谱来证明。与锐钛矿 NFs 和 P25 粉末的混合物相比，分支 TiO 2 异质结构在罗丹明 B 染料溶液的降解中表现出更高的光催化活性，这是由于锐钛矿-金红石异质结增强了电荷分离、金红石 NWs 的高活性以及分支异质结构的比表面积增加的协同效应。
