Effect of Annealing Temperature on the Capacitive and Oxidant-generating Properties of an Electrochemically Reduced TiO2 Nanotube Array. (20th December 2016)

• Record Type: Journal Article
• Authors: Kim, Choonsoo; Lee, Seonggeun; Kim, Seonghwan; Yoon, Jeyong
• Is Part Of: Electrochimica acta. Volume 222(2016)
• Page Start: 1578
• Page End: 1584
• Publication Date: 2016-12-20
• Subjects: TiO2 nanotube array -- electrochemical reduction -- annealing temperature -- polycrystalline structure -- electrochemical properties; Electrochemistry -- Periodicals; Electrochemistry, Industrial -- Periodicals; 541.37
• DOI: 10.1016/j.electacta.2016.11.143
• Languages: English
• ISSNs: 0013-4686

Abstract

Abstract: Recently, the electrochemically reduced TiO2 nanotube array (r-TiO2 NTA) has been an attractive promising material for supercapacitors and anodes for water treatment because of its significantly enhanced capacitive and oxidant-generating electrocatalytic properties. However, most of the previous studies have focused on r-TiO2 NTA prepared at a specific annealing temperature (approximately 450 °C). Accordingly, the effect of annealing temperature on the electrochemical properties of r-TiO2 NTA remained unclear. This study aimed to investigate the capacitive and electrocatalytic properties of r-TiO2 NTAs prepared at various annealing temperatures ranging from 350 to 750 °C. The anatase-dominant r-TiO2 NTAs prepared at low annealing temperatures (350 and 450 °C) exhibited significantly better capacitive and electrocatalytic properties than the rutile-dominant r-TiO2 NTAs prepared at high annealing temperatures (650 and 750 °C). The areal capacitance (14.9 mF/cm 2 ) of r-TiO2 NTA (annealed at 350 °C) was approximately 150 times higher than the areal capacitance of TiO2 NTAs (annealed at 750 °C) (0.1 mF/cm 2 ). The significant production of hydroxyl radicals was found in r-TiO2 NTAs annealed at 350 and 450 °C, whereas no production of hydroxyl radicals was found in r-TiO2 NTA annealed at a higher temperature. This result is attributed to the anatase-dominant phase of r-TiO2 NTAs developed at a low annealing temperature, which contributes to a high doping level, as well as its structural advantage for proton intercalation, yielding a large production of Ti 3+ .