Photoelectrochemical properties of polycrystalline TiO2 electrodes: Anomalous photoeffects

Photoelectrochemical Methods for the Determination of the Flat-Band Potential in Semiconducting Photocatalysts: A Comparison Study

“…Note that the big difference between the results from anodic and cathodic CV curves is not for all studied photocatalysts (Table ), but in most cases approximation of anodic curves gives more adequate values of potential. This corresponds to the recommendation for avoiding anomalous photoeffect during the measurements. , …”

“…This corresponds to the recommendation for avoiding anomalous photoeffect during the measurements. 77,78 Similar to the MS method, the presence of methanol in the electrolyte has no substantial effect on the E FB values estimated by using the GB plots (Figure 5b). In this case, the flat-band potentials are slightly positive (by 0.06−0.12 V) than the corresponding values measured without methanol (Table 2).…”

Interfacial Concentration Gradient as a Source of Anomalous Photoeffect in Photoelectrodes

“…However, PEC experiments do not always behave as predicted. Various anomalous features have been observed during the PEC experiments. − One such feature is usually referred to as the anomalous photoeffect (APE). , In a typical PEC experiment, when light is shined on the photoelectrode, a built-in electric field is generated that shifts the onset potential to more negative values (Figure S1A). Therefore, there is no crossover between the dark current–voltage ( J d – V ) and photocurrent–voltage ( J p – V ) curves.…”

“…Previously, two common mechanisms were identified as the source of the APE: the charge transfer through surface states to adsorbed O 2 and a photoconductive interface. ,, When NCs are adsorbed onto a TiO 2 film, they create a large number of additional surface states on TiO 2 . , Therefore, surface states could have been a source of the APE in NC–TiO 2 photoelectrodes. However, dye–TiO 2 and bare TiO 2 photoelectrodes, which contained no additional surface states, also displayed the APE, leading to doubts about the surface states as a source of APE.…”

“…Previously, two common mechanisms were identified as the source of the APE: the charge transfer through surface states to adsorbed O 2 and a photoconductive interface. 6,11,12 When NCs are adsorbed onto a TiO 2 film, they create a large number of additional surface states on TiO 2 . 2,13 Therefore, surface states could have been a source of the APE in NC−TiO 2 photoelectrodes.…”