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Conductive Cu‐Doped TiO 2 Nanotubes for Enhanced Photoelectrochemical Methanol Oxidation and Concomitant Hydrogen Generation
Author(s) -
Mohajernia Shiva,
Hejazi Seyedsina,
Andryskova Pavlina,
Zoppellaro Giorgio,
Tomanec Ondrej,
Zboril Radek,
Schmuki Patrik
Publication year - 2019
Publication title -
chemelectrochem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.182
H-Index - 59
ISSN - 2196-0216
DOI - 10.1002/celc.201900076
Subject(s) - materials science , photocurrent , copper , anodizing , chemical engineering , doping , hydrogen production , methanol , water splitting , conductivity , nanotube , catalysis , hydrogen , photoconductivity , inorganic chemistry , nanotechnology , photocatalysis , carbon nanotube , chemistry , composite material , metallurgy , optoelectronics , organic chemistry , aluminium , engineering
Cu doping in titania is usually detrimental to the material's photoconductivity, which prevents the use of this combination in photoanodes. In this work, we produce TiO 2 nanotube arrays intrinsically doped with copper and establish sufficient conductivity to use them as efficient photoanodes for methanol oxidation in a photoelectrochemical hydrogen generation setting. Firstly, Cu‐doped TiO 2 nanotubes were produced by anodizing a Ti−Cu binary alloy. By subsequent thermal reduction of the structure in an Ar/H 2 environment, conductive copper‐doped TiO 2 nanotubes (TiCuTN−Ar/H 2 ) can be achieved with an approximately 10 3 times higher conductivity than the non‐reduced material. When these reduced Cu‐doped TiO 2 nanotubes are used as photoanode, copper species embedded in the TiO 2 wall catalyze the methanol oxidation reaction. As a result of the combined effect of conductivity and catalytic effect of Cu, such reduced Cu:TiO 2 nanotubes can generate a photocurrent of 0.76 mA cm −2 at 1 V vs. RHE, under AM1.5 (100 mW/Cm 2 ) irradiation – in a 50 : 50 MeOH/water solution – this is 33 times higher than for pristine Cu:TiO 2 nanotubes.