原子层沉积法制备的 Al 和 Zn 掺杂 TiO 纳米管的光催化和析氢性能。

Photocatalysis and Hydrogen Evolution of Al- and Zn-Doped TiO Nanotubes Fabricated by Atomic Layer Deposition.

机构信息

Department of Materials Science and Engineering , National Tsing Hua University , 101 Section 2, Kuang-Fu Rd. , Hsinchu 30013 , Taiwan.

Department of Materials Science and Engineering , Feng Chia University , 100 Wenhwa Rd. , Seatwen, Taichung 40724 , Taiwan.

出版信息

ACS Appl Mater Interfaces. 2018 Oct 3;10(39):33287-33295. doi: 10.1021/acsami.8b12299. Epub 2018 Sep 20.

DOI:10.1021/acsami.8b12299

PMID:30193072

Abstract

Highly homogeneous Al- and Zn-doped TiO nanotubes were fabricated by atomic layer deposition (ALD) via nanolaminated stacks of binary layers of TiO/AlO and TiO/ZnO, respectively. The bilayers were alternately deposited on the polycarbonate (PC) membrane template by ALD with various cyclic sequences. The nanotubes in a length of 20 μm and a diameter of 220 nm were obtained after removal of the PC membrane by annealing at 450 °C. The effects of doping composition on the photocatalytic and photoelectrochemical (PEC) activities were investigated. Increasing the Al doping reduced the photocatalytic activity of TiO due to formation of charge recombination sites and reduction of hydroxide radicals. In contrast, there was an optimal range of Zn doping to get enhanced photocatalytic activity and higher PEC efficiency. With a doping ratio of 0.01, the hydrogen production rate from water splitting was 6 times higher than that of commercial P25 TiO. The energy-band diagram of Zn-doped TiO determined by ultraviolet photoelectron spectroscopy revealed shift up of the Fermi level to provide more electrons to the conduction band. The photoinduced trapped electrons and holes were detected in Zn-doped TiO by in situ electron paramagnetic resonance spectroscopy, which revealed that Ti sites on the surface and surface oxygen vacancies played a key role in promoting the photocatalytic process.

摘要

高度均匀的 Al 和 Zn 掺杂 TiO 纳米管通过原子层沉积（ALD）制备，方法是分别通过 TiO/AlO 和 TiO/ZnO 的二元层纳米层叠来制备。双层通过 ALD 以各种循环序列交替沉积在聚碳酸酯（PC）膜模板上。通过在 450°C 下退火去除 PC 膜，获得了长 20μm、直径 220nm 的纳米管。研究了掺杂组成对光催化和光电化学（PEC）活性的影响。增加 Al 掺杂由于形成电荷复合位和氢氧根的减少而降低了 TiO 的光催化活性。相比之下，Zn 掺杂存在一个最佳范围以获得增强的光催化活性和更高的 PEC 效率。在掺杂比为 0.01 时，水分解产生氢气的速率比商用 P25 TiO 高 6 倍。紫外光电子能谱确定的 Zn 掺杂 TiO 的能带图显示费米能级向上移动，为导带提供更多电子。通过原位电子顺磁共振光谱检测到 Zn 掺杂 TiO 中的光致俘获电子和空穴，这表明表面的 Ti 位和表面氧空位在促进光催化过程中起着关键作用。