Browsing by Subject "Photoelectrochemical"

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    Hybrid CuFe-CoFe prussian blue catalysts on BiVO4for enhanced charge separation and injection for photoelectrochemical water oxidation
    (American Chemical Society, 2022-12-26) Usman, E.; Vishlaghi, B.; Akbari, Sina Sadigh; Karadaş, F.; Kaya, S.
    The utilization of cocatalysts on the photoelectrode surface is a feasible strategy to achieve a high photocurrent density in the photoelectrochemical water oxidation process. The catalysts can enhance the activity by improving the reaction kinetics, retarding charge carrier recombination, or accumulating charge carriers. In this work, we have utilized a CuFe–CoFe Prussian blue (PB) catalyst layer on the BiVO4 photoanode surface to enhance its water oxidation activity. The hybrid catalyst, in which the semiprecious cobalt ions are partially substituted with earth-abundant copper ions, exhibits 56% higher photocurrent density than the CoFe PB-modified BiVO4. We show that photogenerated hole accumulation is present in the CuFe PB layer, which results in higher charge extraction from the BiVO4 surface. The CoFe PB layer on top of the CuFe one facilitates the charge transfer due to its catalytic activity toward the oxygen evolution reaction (OER).
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    Pushing the limits in photosensitizer-catalyst interaction via a short cyanide bridge for water oxidation
    (Cell Press, 2021-02-24) Ghobadi, Türkan Gamze Ulusoy; Ghobadi, Amir; Demirtaş, M.; Phul, Ruby; Yıldız, E. A.; Yağlıoğlu, H. G.; Durgun, Engin; Özbay, Ekmel; Karadaş, Ferdi
    The realization of high-performance, precious-metal-free, stable, and robust photoanodes for water oxidation is one of the bottlenecks for dye-sensitized water splitting. Herein, we integrate an organic photosensitizer, which absorbs visible light above 500 nm, with a Prussian blue (PB) network to sensitize a visible-light-absorbing semiconductor, WO3. Through comprehensive steady-state and ultrafast transient absorption studies, we show that the coupling of a photosensitizer to a catalyst through a short cyanide bridging group in a PB structure generates appropriate energy levels for an efficient charge transfer from the photosensitizer to the visible-light-absorbing semiconductor. The photoanode retains its structural integrity and high photoelectrochemical activity for at least 2 h of solar irradiation under mildly acidic conditions (pH 3), which reaches around 1.30 mA/cm2 at 1.23 VRHE. This work provides a simple recipe with a toolbox that can be extended to a variety of organic photosensitizers and semiconductors.