Photo‐electrochemical activity and selectivity of nanocrystalline BaTiO₃ electrodes in water oxidation

Abstract

Nanocrystalline BaTiO 3 photocatalysts were prepared by spray-freeze/freezedrying procedure in presence of structure directing gelatin. The synthetic approach yields materials with particle sizes ranging between 20 and 60 nm conforming to cubic perovskite structure. Regardless of the structural differences, the materials show particle size independent bandgap energy of ca. 3.27 eV. All prepared materials are photo-electrochemically active in water oxidation with intrinsic activity decreasing with decreasing particle size. The photoelectrochemical activity of BaTiO 3 in water oxidation is pH dependent with the hole charge transfer processes being significantly suppressed in alkaline media. Such a behavior can be ascribed to deprotonation of surface OH groups encountered in alkaline media that promotes surface state catalyzed electron transfer reactions at the illuminated BaTiO 3 surface. The barium titanate shows the ability to oxidize water with formation of oxygen and ozone. The ozone formation is pronounced on large nanocrystals particularly in acid media. No ozone formation was observed in alkaline solutions.

Strontium-induced phase, energy band and microstructure regulation in Ba1−xSrxTiO3photocatalysts for boosting visible-light photocatalytic activity

“…Sharifian 60 and Gao 61 et al reported that the PZC value of SrTiO 3 synthesized by different methods was close to 8.5. Klusáčková 62 et al believed that the PZC value of BaTiO 3 was between 6 and 7. When an Sr ion partially occupies the A-site ion in BaTiO 3 , the PZC value is close to the PZC value of BaTiO 3 .…”

Recent advances in vacuum- and laser-based fabrication processes for solar water-splitting cells

“…20,22 The selection of semiconductor materials is pivotal, as it directly affects the PEC reaction's efficiency through light absorption and the generation of photoexcited charge carriers. Prominent materials for photoanodes and photocathodes in PECs include metal-oxide semiconductors such as CdS, 23 CdSe, 24 CuO, 25,26 BaTiO 3 , 27,28 BiVO 4 , 29 SrTiO 3 , 30 TiO 2 , 31–34 WO 3 , 35–37 and ZnO. 38–41…”