Functional Grading by Key doping in Catalytic electrodes for Proton Ceramic Cells (FunKeyCat)

• Balcerzak, Daria; Szpunar, Iga; Strandbakke, Ragnar; Saeed, Sarmad Waheed; Bazioti, Kalliopi & Mielewczyk-Gryń, Aleksandra [Vis alle 12 forfattere av denne artikkelen] (2023). Oxide nanoparticle exsolution in Lu-doped (Ba,La)CoO3. CrysteEngComm. ISSN 1466-8033. 25(30), s. 4306–4316. doi: 10.1039/d3ce00422h.
• Zhu, Junjie; Gudmundsdottir, Jonina Björg; Strandbakke, Ragnar; Both, Kevin Gregor; Aarholt, Thomas & Almeida Carvalho, Patricia [Vis alle 12 forfattere av denne artikkelen] (2021). Double Perovskite Cobaltites Integrated in a Monolithic and Noble Metal-Free Photoelectrochemical Device for Efficient Water Splitting. ACS Applied Materials & Interfaces. ISSN 1944-8244. 13(17), s. 20313–20325. doi: 10.1021/acsami.1c01900. Fulltekst i vitenarkiv Vis sammendrag

  Water photoelectrolysis has the potential to produce renewable hydrogen fuel, therefore addressing the intermittent nature of sunlight. Herein, a monolithic, photovoltaic (PV)-assisted water electrolysis device of minimal engineering and of low (in the μg range) noble-metal-free catalysts loading is presented for unassisted water splitting in alkaline media. An efficient double perovskite cobaltite catalyst, originally developed for high-temperature proton-conducting ceramic electrolyzers, possesses high activity for the oxygen evolution reaction in alkaline media at room temperatures too. Ba1–xGd1–yLax+yCo2O6−δ (BGLC) is combined with a NiMo cathode, and a solar-to-hydrogen efficiency of 6.6% in 1.0 M NaOH, under 1 sun simulated illumination for 71 h, is demonstrated. This work highlights how readily available earth-abundant materials and established PV methods can achieve high performance and stable and monolithic photoelectrolysis devices with potential for full-scale applications.

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• Strandbakke, Ragnar (2023). Hydration, stability and electrochemistry of electrode materials for proton ceramic electrochemical cells.
• Vøllestad, Einar (2022). A discussion on the electrochemistry of PCEC electrodes.
• Balaguer, Maria; Wachowski, Sebastian Lech; Szpunar, Iga; Mielewczyk-Gryn, Aleksandra; Sørby, Magnus Helgerud & Carvalho, Patricia A. [Vis alle 10 forfattere av denne artikkelen] (2022). Double perovskite mixed conductors – Hydration, red-ox, structure and stability.
• Strandbakke, Ragnar; Balaguer, María; Carrillo, Alfonso; Wachowski, Sebastian Lech; Mielewczyk-Gryń, Aleksandra & Szpunar, Iga [Vis alle 14 forfattere av denne artikkelen] (2021). Hydration and electrochemistry of mixed conducting cobaltites.
• Strandbakke, Ragnar; Balaguer, María; Carrillo, Alfonso; Wachowski, Sebastian Lech; Mielewczyk-Gryń, Aleksandra & Szpunar, Iga [Vis alle 13 forfattere av denne artikkelen] (2021). Hydration and electrochemistry of mixed conducting cobaltites.
• Norby, Truls Eivind (2021). Electrode kinetics in fuel cells and electrolysers. Vis sammendrag

  Fuel cells constitute the technology of choice to convert hydrogen to electricity, while electrolyzers will be a major technology for producing that hydrogen from electricity from renewable sources, notably indirect (hydroelectric, wind, wave) and direct (photovoltaic) solar energy. They are hence not directly the topic of a workshop on solar fuels, but photoelectrochemical (PEC) electrode kinetics is such a complex matter that it is useful to have electrode kinetics of fuel cells and electrolyzers as kind of reference. Both PEC and fuel cells and electrolyzers have in common that established state-of-the-art versions have aqueous liquid electrolytes, while solid-state electrolytes are of increasing interest. We will cover both, and dwell on various intermediate cases. While various charge carrying ions are in use in different ranges of temperature (O2-, CO32-, H+, OH-, H3O+), protonic electrolytes are most central to PEC and we will focus on them, with examples from proton ceramics, proton exchange membranes (PEMs), hydroxide ion conducting polymers, and surface protonic conduction. The electrode reaction comprises faradaic charge transfer over the electrolyte-electrode interface. This can be an electron transfer (redox) or – in the case of mixed ion electron conducting electrodes – ion transfer, in which case the electron transfer must take place somewhere else, e.g. on the electrode surface. The charge transfer – which is our means of driving the reaction with a voltage or recording a current in a chemically driven fuel cell – may be hindered by the supply of reactants, making adsorption and dissociation appear in the polarization resistance. In addition, diffusion in gas phase, over surfaces, and in the bulk of the electrode or electrolyte slows the reaction further and may eventually limit the current. While charge transfer takes place over the double layer capacitance of the electrolyte-electrode interface, the other processes may store reactants and products as much higher chemical capacitance, whereby the different processes have different time constants and may be separated in impedance spectroscopy. The talk will go through materials, processes, and methods, look to general principles that can be applied across systems and technologies, where possible also photoelectrochemical cells for solar hydrogen and artificial photosynthesis.

• Saeed, Sarmad Waheed & Strandbakke, Ragnar (2020). Resent Activities in FunKeyCat.
• Strandbakke, Ragnar; Saeed, Sarmad Waheed & Carrillo, Alfonso (2019). Exsolution activities in the FunKeyCat project: Exsolving oxide nano-catalysts from cathode materials.
• Saeed, Sarmad Waheed & Strandbakke, Ragnar (2019). FunKeyCat - An Overview.

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