Electrochemical Properties of the Semiconducting TiO₂(Rutile) Single Crystal Electrode

Abstract

The electrochemical behaviour of semiconducting TiO, electrodes has been investigated by means of impedance, current and potential measurements in darkness, and as well in indifferent electrolyte as in redox electrolyte solutions. The results allow the determination of the flat-hand potential and of the position of the energy band edges at the TiO, surface. The data obtained on electrochemical reactivity, both anodically and cathodically, appear to he qualitatively interpretable on the basis of the accepted theories for direct electron transfer at the semiconductor/electrolyte interface. Some particular features inherent to the TiO,/electrolyte system are discussed. Das elektrochemische Verhalten halbleitender Ti0,-Elektroden wurde im Dunkeln durch Impedanz-, Strom-und Spannungsmessungen, sowohl in indifferenten Elektrolyt-wie in Redoxelektrolyt-Losungen untersucht. Die Ergebnisse lassen die Bestimmung des Flachbandpotentials und der energetischen Lage der Bandkanten an der TiO,-Oherflache zu. Es zeigt sich, daR die anodischen und kathodischen Reaktivitatsergebnisse aufgrund der allgemein angenommenen Theorien fur direkten Elektronenubergang an der Halbleiter/Elektrolyt-Phasengrenze qualitativ interpretierbar sind. Einige dem TiO,/Elektrolyt-System inharente Eigentiimlichkeiten werden besprochen.

Investigation on the Kinetics of Electroreduction Processes at Dark TiO2 and SrTiO3 Single Crystal Semiconductor Electrodes

“…[7] qualitatively explains the observed lowering of the voltage dependence of j, i.e., the increase of the experimental Tafel slopes. [7] qualitatively explains the observed lowering of the voltage dependence of j, i.e., the increase of the experimental Tafel slopes.…”

“…[6], we obtain kl 9 ns 9 Cox --(k-1 9 k-2/k2)Cred j : --eN [7] (k-1 -~-kl 9 ns -~-k-2 9 Cred)/k2 "~ Cox Substituting Eq.…”

“…[7] reduces to the experimental one, expressed in Eq. [7] reduces to the experimental one, expressed in Eq.…”

“…[7] reduces to the experimental one, expressed in Eq. [7] is sufficiently large, i.e., when n~ largely exceeds the value corresponding to electrode equilibrium. [7] is sufficiently large, i.e., when n~ largely exceeds the value corresponding to electrode equilibrium.…”

Mechanisms of Charge Transfer at the Semiconductor‐Electrolyte Interface: I . Kinetics of Electroreduction at Dark of and in Aqueous Solution on a Sintered Nb‐doped Electrode: Influence of pH

“…[8] is also predicted by Ullman, according to whom it is ~--sat ~-(qDnND/I) (e-#/Daw [r [13] and K --" Dn/~c Z Daw (,~) Vs [14] where Dn ----~kT/q is the diffusion coefficient of the electrons, Z is the Debye length of the space charge region [8] is also predicted by Ullman, according to whom it is ~--sat ~-(qDnND/I) (e-#/Daw [r [13] and K --" Dn/~c Z Daw (,~) Vs [14] where Dn ----~kT/q is the diffusion coefficient of the electrons, Z is the Debye length of the space charge region…”