Spray pyrolytically deposited nanoporous Ti⁴⁺ doped hematite thin films for efficient photoelectrochemical splitting of water

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• 作者：Saroj Kumari ; Aadesh P. Singh ; Sonal ; Dinesh Deva ; Rohit Shrivastav ; Sahab Dass ; Vibha R. Satsangi
• 关键词：Hematite ; Photoelectrochemical ; Ti doping ; Spray-pyrolysis ; Hydrogen
• 刊名：International Journal of Hydrogen Energy
• 出版年：2010
• 出版时间：May 2010
• 年：2010
• 卷：35
• 期：9
• 页码：3985-3990
• 全文大小：666 K

文摘

Nanoporous hematite (α-Fe₂O₃) thin films doped with Ti⁴⁺ deposited by spray-pyrolysis were successfully used in photoelectrochemical splitting of water for solar hydrogen production. X-ray diffraction, field emission scanning electron microscopy, UV–visible absorption and photoelectrochemical studies have been performed on the undoped and Ti⁴⁺ doped hematite thin films. Morphology of α-Fe₂O₃ thin films was observed to be nanoporous, with increased porosity (pore size 12 to 20 nm) on increasing doping concentration. A significant decrease in the bandgap energy from 1.95 to 1.27 eV was found due to doping. α-Fe₂O₃ film doped with 0.02 M Ti⁴⁺ ions exhibited best solar to hydrogen conversion efficiency (photoconversion efficiency) of 1.38 % at 0.5 V/SCE. Highest photocurrent densities of 0.34 mA/cm² at zero bias and 1.98 mA/cm² at 0.5 V/SCE were obtained by incorporating 0.02 M Ti⁴⁺ in α-Fe₂O₃, which are significantly larger than earlier reported values. Donor density (30.8 × 10²⁰ cm⁻³) and flatband potential (−1.01 V/SCE) obtained were also maximum for this sample. Hydrogen collected in 1 hr at Pt electrode with the best photoelectrode was 2.44 mL with 150 mW/cm² visible light source.