Effect of NH4F concentration and controlled-charge consumption on the photocatalytic hydrogen generation of TiO2 nanotube arrays. (10th February 2015)

• Record Type: Journal Article
• Authors: Xue, Yujing; Sun, Yan; Wang, Guixin; Yan, Kangping; Zhao, Jingyong
• Is Part Of: Electrochimica acta. Volume 155(2015)
• Page Start: 312
• Page End: 320
• Publication Date: 2015-02-10
• Subjects: TiO2 nanotubes -- NH4F concentration -- anodization charge -- hydrogen production -- photoelectrochemical performance; Electrochemistry -- Periodicals; Electrochemistry, Industrial -- Periodicals; 541.37
• DOI: 10.1016/j.electacta.2014.12.134
• Languages: English
• ISSNs: 0013-4686

Abstract

Abstract: Self-organized TiO2 nanotube arrays (TiO2 Nts) for hydrogen evolution were successfully fabricated by electrochemical anodization in ethylene glycol-based electrolytes with various NH4 F concentrations. Hydrogen production by photocatalytic water splitting was performed in a two-compartment photoelectrochemical (PEC) cell without any applied voltage. The effect of NH4 F concentration on the morphological structure, PEC performance and hydrogen evolution of TiO2 samples were systematically investigated. TiO2 anodized with 0.50 wt% of NH4 F concentration for 60 min exhibited highest hydrogen evolution of 2.53 mL h −1 cm −2 and maximum photoconversion efficiency of 4.39%. Based on the above results and the different current-time curves during anodization processes, another series of TiO2 nanotube arrays samples with the equal charge consumption (designated as TiO2 Nts-EC) were synthesized by controlling the anodization time in electrolytes containing different NH4 F concentrations. Compared with TiO2 Nts prepared at the same NH4 F concentration for 60 min, hydrogen production and PEC properties of TiO2 Nts-EC samples have been obviously enhanced, especially for the sample prepared at 1.25 wt% NH4 F concentrations. Moreover, despite the difference of NH4 F concentration in electrolyte, the TiO2 Nts-EC samples exhibit comparable PEC performances. These results indicated that the anodization charge-density play a crucial role in the hydrogen generation of TiO2 Nts. The results benefit the enhancement of the hydrogen production of TiO2 Nts.