Browsing by Author "Phul, Ruby"

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Cyanide linkage isomerization induced by cobalt oxidation-state changes at a Co-Fe prussian-blue analogue/ZnO interface
(Wiley-VCH Verlag GmbH & Co. KGaA, 2024-10-28) De, R.; Hermesdorf, M.; Bera, A.; Phul, Ruby; Gawlik, A.; Plentz, J.; Oschatz, M.; Karadaş, Ferdi; Dietzek-Ivanšić, B.
Understanding the interfacial composition in heterostructures is crucial for tailoring heterogenous electrochemical and photoelectrochemical processes. This work aims to elucidate the structure of a series of Co-Fe Prussian blue analogue modified ZnO (PBA/ZnO) electrodes with interface-sensitive vibrational sum frequency generation (VSFG) spectroscopy. Our measurements revealed, for the first time, a cyanide linkage isomerism at the PBA/ZnO interface, when the composite is fabricated at elevated temperatures. In situ VSFG spectro-electrochemistry measurements correlate the ${Co}^{II}→{Co}^{III}$ oxidation with the flip of the bridging CN ligand from Co-NC-Fe coordination mode to a Co-CN-Fe one. Photoluminescence measurements and X-ray photoelectron spectroscopy reveal that this unprecedented linkage isomerism originates from surface defects, which act as oxidation sites for the PBA. The presence of such surface defects is correlated with the fabrication temperature for PBA/ZnO. Thus, this contribution identifies the interplay between the surface states of the ZnO substrates and the chemical composition of PBA at the ZnO surface, suggesting an easily accessible approach to control the chemical composition of the interface.
Open Access
Polystyrene-supported catalysts
(CRC Press, LLC, 2024-07-26) Khokhar, Deepali; Kour, Manjinder; Phul, Ruby; Sharma, Alpesh Kumar; Jadoun, Sapana
Recent development of sustainable synthetic procedures and green technologies are vital for progressing the quality of living. With the limited availability of resources, significance of recyclable catalysts become more promising in the era of climate crisis. Apart from inorganic catalysts, polymer-supported catalysts have gained considerable attention possessing properties like inertness, non-volatility, non-toxicity, reusability, and insolubility which offers an easy synthetic path, materials availability, and higher efficiency. Amongst polymeric support, the polystyrene-based catalyst support is extensively employed as intermediates in various organic synthesis reactions, namely allylboration of aldehydes, epoxidation of alkenes, and various cross-coupling reactions that are sustainable and provident. This book chapter focuses on various polystyrene-based support catalyst and their uses in organic synthesis, pharmaceuticals, and chemical industries.
Open Access
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.