Photo-chargeable and dischargeable TiO 2 and WO 3 heterojunction electrodes

Hyunwoong Park, Ayoung Bak, Tae Hwa Jeon, Seungdo Kim, Wonyong Choi

Research output: Contribution to journalArticlepeer-review

68 Scopus citations

Abstract

TiO 2 and WO 3 heterojunction electrodes are studied for their bi-functionality on harvesting light and storing energy. Both semiconductors are fabricated either 'single' (mixed) electrodes or two different electrodes galvanically coupled in a mixed electrolyte of 0.1M sodium formate and 0.1M sodium chloride. Irradiation of AM 1.5-light shifts the open circuit potentials (OCPs) of the mixed and coupled electrodes from around -0.1V SCE (dark OCPs) to a potential range between -0.8 and -0.5V SCE, which slowly return to their respective dark OCPs over a period of around 14h. Such discharging periods are significantly influenced by the irradiation (photocharging) time and weight or area ratios of TiO 2 and WO 3. When the TiO 2 and WO 3 mixed electrodes are galvanically coupled to stainless steel electrodes for application to anticorrosion, the mixed potentials of the couple are maintained at ca. -0.4V SCE over 10h even after light off. The measured galvanic currents verify that the photogenerated electrons of TiO 2 flow to WO 3 (charging) and even overflow to the steel (cathodic protection) during the irradiation, while the stored electrons at WO 3 flow to the galvanically coupled steel electrodes directly or through the TiO 2 upon light off.

Original languageEnglish
Pages (from-to)74-80
Number of pages7
JournalApplied Catalysis B: Environmental
Volume115-116
DOIs
StatePublished - 5 Apr 2012

Keywords

  • Anticorrosion
  • Artificial photosynthesis
  • Battery
  • Discharging
  • Galvanic
  • Solar

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