Investigation of porosity and heterojunction effects of a mesoporous hematite electrode on photoelectrochemical water splitting

Jingling Liu, Muhammad Shahid, Young Seon Ko, Eunchul Kim, Tae Kyu Ahn, Jong Hyeok Park, Young Uk Kwon

Research output: Contribution to journalArticle

26 Citations (Scopus)

Abstract

In this paper, we report the porosity and heterojunction effects of hematite (α-Fe2O3) on the photoelectrochemical (PEC) water splitting properties. The worm-like mesoporous hematite thin films (MHFs) with a pore size of ∼9 nm and a wall thickness of ∼5 nm were successfully obtained through the self-assembly process. MHFs formed on FTO showed much better PEC properties than those of nonporous hematite thin films (NP-HF) owing to the suppression of charge recombination. The PEC data of MHFs under front and back illumination conditions indicated that the porous structure allows the diffusion of electrolyte deep inside the MHF increasing the number of holes to be utilized in the water oxidation reaction. A heterojunction structure was formed by introducing a thin layer of SnO2 (∼15 nm in thickness) between the MHF and FTO for a dramatically enhanced PEC response, which is attributed to the efficient electron transfer. Our spectroscopic and electrochemical data show that the SnO2 layer functions as an efficient electron transmitter, but does not affect the recombination kinetics of MHFs.

Original languageEnglish
Pages (from-to)9775-9782
Number of pages8
JournalPhysical Chemistry Chemical Physics
Volume15
Issue number24
DOIs
Publication statusPublished - 2013 Jun 28

All Science Journal Classification (ASJC) codes

  • Physics and Astronomy(all)
  • Physical and Theoretical Chemistry

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