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Commercially Available WO 3 Nanopowders for Photoelectrochemical Water Splitting: Photocurrent versus Oxygen Evolution
Author(s) -
Reinhard Sandra,
Rechberger Felix,
Niederberger Markus
Publication year - 2016
Publication title -
chempluschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.801
H-Index - 61
ISSN - 2192-6506
DOI - 10.1002/cplu.201600241
Subject(s) - photocurrent , electrolyte , oxygen evolution , water splitting , oxygen , materials science , annealing (glass) , photoelectrochemical cell , photoelectrochemistry , chemical engineering , electrochemistry , chemistry , electrode , optoelectronics , photocatalysis , catalysis , metallurgy , organic chemistry , engineering
WO 3 photoanodes with remarkable photocurrent densities are presented. These photoanodes were prepared from three different commercially available WO 3 nanopowders. Doctor blading of the nanopowders followed by a short annealing in air led to nanostructured films. The best photoanode showed a photocurrent density of 3.5 mA cm −2 at 1.23 V vs. RHE in 1 m CH 3 SO 3 H under AM 1.5 G illumination (100 mW cm −2 ), surpassing values reported so far for bare WO 3 photoanodes. The study also showed that the photocurrent was strongly dependent on the electrolyte, indicating oxidation of the electrolyte rather than of water. Oxygen evolution measurements performed in different electrolytes revealed that the amounts of oxygen were highly dependent on the electrolyte. By comparing the photocurrent values in the different electrolytes with the amount of evolving oxygen, it was found that the electrolyte producing the highest photocurrent was the electrolyte with the lowest oxygen evolution. Stability measurements showed that the more oxygen is produced, the less stable is the photoanode. These results clearly underline the difficulty to correlate the photocurrent values with oxygen evolution, drawing the attention to one of the major limitations of photoelectrochemical water splitting.