Surface photovoltage experiments on SrTiO3 electrodes

Abstract

Electronic surface states play a significant role in charge transfer between the electrolyte and the n-type SrTiO2 semiconducting electrodes used in the photoelectrolysis of water. To clarify the role of these states, we have measured the wavelength response of the photovoltage developed between the SrTiO3 surface and a vibrating Au reference electrode, both in vacuum and in a water vapor ambient. When the SrTiO3 is exposed to sub-band-gap radiation, the amplitude and sign of the photovoltage vary with photon energy. Significant changes in the spectrum result from the introduction of water vapor. The energy-dependent structure is interpreted in terms of photon-induced electronic transitions between the states near the surface and conduction or valence band states.

Semiconductor based photoelectrochemical cells for solar energy conversion—An overview

“…A historical account of the field of semZconductor electrochemistry is given in table 2. Williams (1960) Green (1959) ; Myamlin and Pleskov (1967) ; Gerischer (1970) Body 1968Fnjishima and Honda (1972) Gerischer (1975) Wrighton et al (1976) ; Mavroides et d (1975Mavroides et d ( , 1976Mavroides et d ( , 1978 ; Watanabe et al (1976) Yeneyama et al Nozik {1976, 1977 ; Ohashi et al (1977a) Frank and Bard (1975) Ellis et al (1976) ; Hodes et al (1976); Heller (1976) Ghosh andMaruska (1977) Tributseh et al 0977) Gerischer (1977) ; Bard and Wrighton…”

“…The conduction band should lie at a position more negative than the reversible hydrogen potential at a given pH. The band gap of the sc must be at least about 1" 8 eV (Mavroides et al 1976: Mavroides 1978) (i.e., 1 "23 V+ overvoltage) for the electrode reactions to take place. The overvoltages at the respective electrodes must be small.…”

Titanate biomaterials with enhanced antiinflammatory properties

“…Titanium dioxide is a member of a group of semiconductors which are used industrially as photocatalysts to generate ROS to purify water and degrade industrial waste 7–9. This group includes perovskites SrTiO 3 and BaTiO 3 in which the titanium cations have octahedral oxygen coordination, and all share similar surface structures and electronic states 10–12. Central to the photocatalytic mechanism is the ability of titanium ions in these crystalline structures to readily and reversibly change valence states from +4 to +3 13–15.…”

“…[7][8][9] This group includes perovskites SrTiO 3 and BaTiO 3 in which the titanium cations have octahedral oxygen coordination, and all share similar surface structures and electronic states. [10][11][12] Central to the photocatalytic mechanism is the ability of titanium ions in these crystalline structures to readily and reversibly change valence states from þ4 to þ3. [13][14][15] When a high energy photon strikes these surfaces an oxygen vacancy defect is created with a charge of 2e À .…”

Enhanced photoelectrolysis of water with photoanode Nb:SrTiO3

“…11,12 Figure 3 is a simplified energy diagram of a photoelectrolysis cell, consisting of a n-type semiconductor anode, a electrolyte, and a Pt counterelectrode. 11,12 Figure 3 is a simplified energy diagram of a photoelectrolysis cell, consisting of a n-type semiconductor anode, a electrolyte, and a Pt counterelectrode.…”