Interfacial Schottky junctions modulated by photo-piezoelectric band bending to govern charge carrier migration for selective H2O2 generation

Kien Tiek Wong, Choe Earn Choong, In Wook Nah, Sang Hyoun Kim, Byong Hun Jeon, Yeomin Yoon, Eun Ha Choi, Min Jang

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15 Scopus citations

Abstract

A major challenge faced by most systems is the dissociation of O−O bonding on H2O2 by subsequent electron (e-) reduction. This study investigates interfacial charge transfer by manipulating e- flows through a deflexed band potential on polarized piezoelectric BiFO3 (BFO). The H2O2 accumulation via coupling with the photocatalyst BiOCl/BiVO4 (BCV) was highly effective since the Schottky barrier height (SBH) formed within the heterojunction composite shifted according to the surface polarity of BFO. Additionally, the constant alternating surface charge on BFO, reduced the SBH, forcing the photoexcited e- to flow from BCV→BFO for effective H2O2 production, while restricting decomposition of H2O2 during downshifted band potential (positive surface) as high SBH discontinuing the electrons flow from BCV→BFO. The high interfacial charge transfer resistance (Rct) was also critical for H2O2 accumulation, since it is unfavorable for H2O2 dissociation (H2O2/·OH, +0.39 V) despite the presence of a high band potential (+0.16 eV) on the opposite surface's upshifted band. The formation rate (kf: 1.13 µmol L−1 min−1) of H2O2 was calculated much higher than decomposition rate (kd: 0.01 min−1). Additionally, the RRDE results indicated favorable 2e- transfer with > 90 % selectivity for H2O2. Results from ESR DMPO-·OH abduction and atrazine degradation show an insignificant concentration of ·OH has been produced. This work provides an effective strategy to regulate semiconductors' surface junction by piezoelectric polarization for selective H2O2 generation.

Original languageEnglish
Article number121581
JournalApplied Catalysis B: Environmental
Volume315
DOIs
StatePublished - 15 Oct 2022

Bibliographical note

Funding Information:
This research was supported by Basic Science Research Program through the National Research Foundation of South Korea (NRF) funded by the Ministry of Education (No. 2021R1A6A1A03038785 ) and the National Research Foundation of Korea (NRF) grant funded by the Ministry of Science and ICT (MSIT) of South Korea government (No. 2020R1F1A1075839 ).

Publisher Copyright:
© 2022 Elsevier B.V.

Keywords

  • Bismuth ferrite
  • Hydrogen peroxide
  • Photo-piezocatalysis
  • Polarization
  • Schottky barrier

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