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Energy Materials Laboratory © 2014, EML | All Rights Reserved.

Photoelectrochemical Water Splitting

Our research goal is developing novel materials for energy applications with the current emphasis on non-toxic, earth-abundant, and low-cost
compounds for photovoltaic and photocatalytic applications.

Photoelectrochemical Water Splitting

Photoelectrochemical Water Splitting

A promising and environmental-friendly way of producing renewable energy is photoelectrochemical (PEC) water splitting, where the sun light and semiconducting materials are used to decompose water into hydrogen and oxygen gases. The traditional material for this purpose is TiO2 but its large bandgap (~3.0 eV) poses a severe limitation in terms of efficient utilization of the solar spectrum. As an alternative to TiO2, we are working on developing Cu(In,Ga)Se2 photocathodes for hydrogen evolution and BiVO4 photoanodes for oxygen evolution; by connecting them in tandem configuration, we aim to build PEC cells for unassisted (i.e. no applied bias) photocatalytic water splitting.

  • Photocathode for hydrogen evolution reaction(CIGS)

    Currently, we are working on the synthesis of both CIGS and BiVO4 and testing the suitability of them as a photoelectrode where water splitting reaction take place. Our ultimate goal is producing unassisted PEC tandem cell, which is solely driven by solar illumination, consisting of highly efficient and stable photoelectrodes with low manufacturing costs.

    A promising and environmental-friendly way of producing hydrogen and oxygen gases is water photolysis, where solar energy generates electron-hole pairs in a photocatalytic material which, in turn, reduce water into hydrogen (at photocathode) and oxidize it into oxygen (at photoanode). A quaternary chalcogenide compound CIGS emerged as a promising candidate as an electrode on the cathode side. However, long-term stability of CIGS-based photoelectrodes in aqueous solution is a concern. We study the degradation mechanism of CIGS photoelectrode and how to prevent it. Additionally, we consider the application of CIGS-based photocathode for CO2 reduction

    Related publications

    - B. Koo, S. Nam, R. Haight, S. Kim, S. Oh, M. Cho, J. Oh, J. Lee, B. Ahn, B. Shin. ACS Appl. Mater. Interfaces. 9, 5279 (2017).
    - B. Koo, J. Lee, D. Shin, B. Ahn, B. Shin. Thin Solid Films. 603, 134 (2016).

  • Photoanode for oxygen evolution reaction(BiVO4)

    Among various photoanode candidates, BiVO4 based photoanode is a promising photoelectrode for solar-driven water splitting applications in photoelectrochemical (PEC) devices because of its easy separation of the evolving gases (H2 an O2) with separated two-electrodes and high oxygen evolution reaction (OER) activity that achieving from applying with external bias and tandem cell configurations. However, PEC performances of the fabricated BiVO4 are varied and do not reproducible even though the BiVO4 is fabricated with the similar recipe using a metal-organic decomposition (MOD) process that one of widely used solution based techniques. Therefore, we focus on the fabrication of a highly efficient and reproducible BiVO4 based photoanode by using various strategies such as introduction of a buffer layer, decoration of co-catalysts and engineering the chemical compositions (secondary element doping) of BiVO4 during the fabrication of BVO film.

    Related publications

    - S. Byun, B. Kim, S. Jeon, B. Shin. J. Mater. Chem. A. 5, 6905-6913 (2017).