Exploiting direct current plasma electrolytic oxidation to boost photoelectrocatalysis

Silvia Franz, Hamed Arab, Andrea Lucotti, Chiara Castiglioni, Antonello Vicenzo, Federico Morini, Massimiliano Bestetti

Research output: Contribution to journalArticlepeer-review

5 Citations (Scopus)


In this study, we report an investigation of the photoelectrochemical activity of TiO2 films formed by DC plasma electrolytic oxidation (PEO) at a variable potential in a sulfuric acid electrolyte at 0 and 25C. The surface morphology was mainly determined by the oxide-forming potential. X-Ray Diffraction and Raman analyses showed that the relative amount of the anatase and rutile phases varied from 100% anatase at low potential (110–130 V) to 100% rutile at high potential (180–200 V), while mixed-phase oxide films formed at intermediate potential. Correspondingly, the band gap of the TiO2 films decreased from about 3.20 eV (pure anatase) to 2.94 eV (pure rutile) and was red-shifted about 0.1 eV by reducing the electrolyte temperature from 25C to 0C. Glow-Discharge Optical Emission Spectroscopy (GD-OES) and X-ray Photoelectron Spectroscopy (XPS) analyses evidenced S-containing species located preferentially close to the TiO2/Ti interface. The photoelectrochemical activity was assessed by measuring the incident photon-to-current efficiency (IPCE) under Ultraviolet C (UV-C) irradiation, which showed a non-gaussian normal trend as a function of the PEO cell potential, with maximum values exceeding 80%. Photoelectrocatalytic activity was assessed by decolorization of model solutions containing methylene blue. Photoanodes having higher IPCE values showed faster decolorization kinetics.

Original languageEnglish
Article number325
Issue number3
Publication statusPublished - Mar 2020


  • Anatase
  • Photoelectrocatalysis
  • Plasma electrolytic oxidation
  • Rutile
  • TiO
  • Titanium dioxide

ASJC Scopus subject areas

  • Catalysis
  • Physical and Theoretical Chemistry

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