Electronic Surface Level Positions of WO3 Thin Films for Photoelectrochemical Hydrogen Production
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- 作者：L. Weinhardt ; M. Blum ; M. Bä ; r ; C. Heske ; B. Cole ; B. Marsen ; E. L. Miller
- 刊名：Journal of Physical Chemistry C
- 出版年：2008
- 出版时间：February 28, 2008
- 年：2008
- 卷：112
- 期：8
- 页码：3078 - 3082
- 全文大小：168K
- 年卷期：v.112,no.8(February 28, 2008)
- ISSN：1932-7455
文摘
Polycrystalline WOB>3 thin films for photoelectrochemical hydrogen production were investigated usingphotoelectron spectroscopy and inverse photoemission. First, we report on a careful study to minimize X-rayand electron beam-induced degradation. Second, we combined ultraviolet photoelectron spectroscopy andinverse photoemission to determine the surface positions of the valence and conduction band edges, respectively,and the work function (i.e., the position of the vacuum level). This allows us to paint a completely experiment-based picture of the WO3 surface level positions, which are of central relevance for the photoelectrochemicalactivity of such surfaces. We find the WO3 surface to be wide gap [3.28 (±0.14) eV] and n-type, with theconduction band minimum 0.39 (±0.10) eV above the Fermi level and 0.31 (±0.11) eV above the H+/H2reduction potential. The valence band maximum is 2.89 (±0.10) eV below the Fermi level and 1.74 (±0.11)eV below the H2O/O2 oxidation potential.