He Shiman, Meng Yuying, Cao Yangfei, Huang Senchuan, Yang Jingling, Tong Shengfu, Wu Mingmei
School of Chemistry, Sun Yat-Sen University, No. 135, Xingang Xi Road, Guangzhou 510275, China.
Nanomaterials (Basel). 2018 Nov 28;8(12):983. doi: 10.3390/nano8120983.
TiO₂ is one of the most attractive semiconductors for use as a photoanode for photoelectrochemical (PEC) water oxidation. However, the large-scale application of TiO₂ photoanodes is restricted due to a short hole diffusion length and low electron mobility, which can be addressed by metal doping and surface decorating. In this paper we report the successful synthesis of hierarchical Ta doped TiO₂ nanorod arrays, with nanoparticles on the top (Ta:TiO₂), on F-doped tin oxide (FTO) glass by a hydrothermal method, and its application as photoanodes for photoelectrochemical water oxidation. It has been found that the incorporation of Ta in the TiO₂ lattice can decrease the diameter of surface TiO₂ nanoparticles. Ta:TiO₂-140, obtained with a moderate Ta concentration, yields a photocurrent of ∼1.36 mA cm at 1.23 V vs. a reversible hydrogen electrode (RHE) under FTO side illumination. The large photocurrent is attributed to the large interface area of the surface TiO₂ nanoparticles and the good electron conductivity due to Ta doping. Besides, the electron trap-free model illustrates that Ta:TiO₂ affords higher transport speed and lower electron resistance when under FTO side illumination.
二氧化钛是用作光电化学（PEC）水氧化光阳极最具吸引力的半导体之一。然而，由于空穴扩散长度短和电子迁移率低，二氧化钛光阳极的大规模应用受到限制，金属掺杂和表面修饰可以解决这些问题。在本文中，我们报道了通过水热法在氟掺杂氧化锡（FTO）玻璃上成功合成了顶部带有纳米颗粒的分级Ta掺杂二氧化钛纳米棒阵列（Ta:TiO₂），并将其用作光电化学水氧化的光阳极。研究发现，Ta掺入TiO₂晶格中可减小表面TiO₂纳米颗粒的直径。在中等Ta浓度下获得的Ta:TiO₂-140，在FTO侧光照下，相对于可逆氢电极（RHE）在1.23 V时产生的光电流约为1.36 mA cm² 。大的光电流归因于表面TiO₂纳米颗粒的大界面面积以及Ta掺杂带来的良好电子导电性。此外，无电子陷阱模型表明，Ta:TiO₂在FTO侧光照下具有更高的传输速度和更低的电子电阻。
