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Solvothermal Synthesis of Molybdenum-Tungsten Oxides and Their Application for Photoelectrochemical Water Splitting

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  • Dmitri Spetter, Johannes Gutenberg University Mainz
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  • Muhammad Nawaz Tahir, King Fahd Univ Petr & Minerals, King Fahd University of Petroleum & Minerals, Dept Chem
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  • Jan Hilgert, Johannes Gutenberg University Mainz
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  • Ibrahim Khan, Ctr Excellence Nanotechnol
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  • Ahsanulhaq Qurashi, King Fahd Univ Petr & Minerals, King Fahd University of Petroleum & Minerals, Dept Chem
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  • Hao Lu, Max Planck Institute for Polymer Research
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  • Tobias Weidner
  • Wolfgang Tremel, Johannes Gutenberg University Mainz

Molybdenum and tungsten oxides are of interest as semiconductors for the production of clean and sustainable energy. Here we show that synergistic effects arising from a combination of noncrystallinity and plasmonic resonance in mixed molybdenum/tungsten oxides can lead to improved efficiency for the photoelectrochemical (PEC) splitting of water. The quasi-binary Mo/W oxides were synthesized solvothermally on a gram scale. Size, structure, morphology, and electronic properties of the as-prepared microspheres were characterized by scanning and transmission electron microscopy (SEM, TEM), X-ray diffraction (XRD), Raman, optical absorption (UV-vis), and X-ray photoelectron spectroscopy (XPS). Molybdenum oxide benefits from W-substitution and the concomitant metal reduction. The increased number of charge carriers leads to higher photocurrents for Mo0.5W0.5O2.1 (5.25 mA cm(-2)), the most reduced phase compared to Mo0.89W0.11O2.7 (1.75 mA cm(-2)). Long-term photocurrent stability tests (2000 s) under photoillumination confirmed the chemical stability of Mo/W oxides under sunlight. The improved PEC performance is attributed to the synergistic effect of increased charge carrier concentration due to metal reduction, suppressing the formation of crystalline metallic oxides through disorder, and tuning the absorption in the visible and near-IR range by the formation of W5+ and Mo5+ sites.

Original languageEnglish
JournalACS Sustainable Chemistry & Engineering
Pages (from-to)12641-12649
Number of pages17
Publication statusPublished - 2018
Externally publishedYes

    Research areas

  • Molybdenum oxide, Tungsten oxide, Molybdenum-tungsten oxide, Solvothermal synthesis, Nanocatalysis, Photoelectrochemical hydrogen evolution, SOLID-SOLUTIONS, METAL-OXIDES, THIN-FILMS, WO3, OXIDATION, PERFORMANCE, NANOSHEETS, CATALYSTS, TRIOXIDE, PLANET

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