Hybrid photoanodes for visible light-driven water oxidation: the beneficial and detrimental effects of nickel oxide cocatalyst
peer-reviewed
Erstveröffentlichung
2020-08-27Autoren
Longchin, Pimchanok
Mitoraj, Dariusz
Reyes, Oliver Mendoza
Adler, Christiane
Wetchakun, Natda
Wissenschaftlicher Artikel
Erschienen in
Journal of Physics: Energy ; 2 (2020), 4. - Art.-Nr. 044001. - eISSN 2515-7655
Link zur Originalveröffentlichung
https://dx.doi.org/10.1088/2515-7655/abaec9Fakultäten
Fakultät für NaturwissenschaftenInstitutionen
Institut für ElektrochemieDokumentversion
Veröffentlichte Version (Verlags-PDF)Zusammenfassung
AbstractHybrid photoanodes comprising polymer-based light absorbers coupled to oxygen-evolving cocatalysts represent a promising, yes still underdeveloped, approach to photoelectrochemical splitting of water into hydrogen and oxygen. In this study, we investigate nickel oxide (NiOx) nanoparticles as a water oxidation catalyst in hybrid photoanodes based on polymeric carbon nitride (CNx) supported on electron-collecting mesoporous TiO2 support. The performance of the resulting TiO2–CNx/NiOx photoanodes is evaluated with respect to our previous results on hybrid TiO2–CNx photoanodes modified with IrOx and CoO(OH)x cocatalysts. The deposition of NiOx into TiO2–CNx photoanodes enhances significantly the photocurrent (from <8 μA to >250 μA cm–2 at 1.23 V vs. RHE) under visible light irradiation (λ > 420 nm, ∼200 mW cm−2) and triggers the photoelectrocatalytic oxygen evolution. No oxygen evolution was observed without a cocatalyst. As compared to photoanodes modified with IrOx or CoO(OH)x, the TiO2–CNx/NiOx photoanodes excel by the very negative photocurrent onset potential (0 V vs. RHE), which we ascribe to good hole-extracting properties of NiOx. However, the comparatively low Faradaic efficiencies for oxygen evolution (∼18%) and dramatically decreased operational stability of the photoanodes indicate that the extracted holes do not efficiently oxidize water to dioxygen, but instead accumulate in the NiOx particles and increase thus the oxidative photodegradation of the photoanodes. Our study highlights the fact that employing outstanding electrocatalysts like NiOx in photoelectrochemical water-splitting systems does not necessarily lead to satisfactory results, especially when the photoelectrode cannot be operated at optimal pH due to light absorber stability issues.
DFG-Projekt uulm
TRR 234 Teilprojekt B06 / Molekular funktionalisierte Kohlenstoffnitrid-Polymere für die lichtgetriebene Wasserspaltung / DFG / 364549901
Wird ergänzt durch
https://iopscience.iop.org/article/10.1088/2515-7655/abaec9#Schlagwörter
[GND]: Titandioxid | Fotoelektrochemie[LCSH]: Titanium dioxide | Photoelectrochemistry
[Freie Schlagwörter]: polymeric carbon nitride | water splitting | charge separation | oxygen evolution reaction
[DDC Sachgruppe]: DDC 540 / Chemistry & allied sciences
Metadata
Zur LanganzeigeDOI & Zitiervorlage
Nutzen Sie bitte diesen Identifier für Zitate & Links: http://dx.doi.org/10.18725/OPARU-50320
Longchin, Pimchanok et al. (2023): Hybrid photoanodes for visible light-driven water oxidation: the beneficial and detrimental effects of nickel oxide cocatalyst. Open Access Repositorium der Universität Ulm und Technischen Hochschule Ulm. http://dx.doi.org/10.18725/OPARU-50320
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