Design aspects of all atomic layer deposited TiO2–Fe2O3 scaffold-absorber photoanodes for water splitting

Arto Hiltunen, Tero-Petri Ruoko, Tomi Iivonen, Kimmo Lahtonen, Harri Ali-Löytty, Essi Sarlin, Mika Valden, Markku Leskelä, Nikolai Tkachenko

    Research output: Contribution to journalArticleScientificpeer-review

    5 Citations (Scopus)

    Abstract

    Iron and titanium oxides have attracted substantial attention in photoelectrochemical water splitting applications. However, both materials suffer from intrinsic limitations that constrain the final device performance. In order to overcome the limitations of the two materials alone, their combination has been proposed as a solution to the problems. Here we report on the fabrication of an atomic layer deposited (ALD) Fe2O3 coating on porous ALD-TiO2. Our results show that successful implementation requires complete mixing of the TiO2 and Fe2O3 layers via annealing resulting in the formation of a photoactive iron titanium oxide on the surface. Moreover, we found that incomplete mixing leads to crystallization of Fe2O3 to hematite that is detrimental to the photoelectrochemical performance. IPCE and transient photocurrent measurements performed using UV and visible light excitation confirmed that the iron titanium oxide extends the photocurrent generation to the visible range. These measurements were complemented by transient absorption spectroscopy (TAS), which revealed a new band absent in pristine hematite or anatase TiO2 that we assign to charge transfer within the structure. Taken together, these results provide design guidelines to be considered when aiming to combine TiO2 and Fe2O3 for photoelectrochemical applications.
    Original languageEnglish
    Pages (from-to)2124-2130
    JournalSustainable Energy & Fuels
    Volume2
    Issue number9
    DOIs
    Publication statusPublished - 31 Jul 2018
    Publication typeA1 Journal article-refereed

    Keywords

    • Water splitting
    • Atomic layer deposition (ALD)
    • Titanium dioxide
    • Hematite
    • Cellulose
    • Template

    Publication forum classification

    • Publication forum level 1

    ASJC Scopus subject areas

    • Electrochemistry
    • Renewable Energy, Sustainability and the Environment
    • Surfaces, Coatings and Films

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