Henrik Petlund

• Petlund, Henrik; Tezel, Elif; Sypalyte, Goda; Molina, M. Asunción; Costley-Wood, Lucy & Szilagyi, Petra Agota [Vis alle 7 forfattere av denne artikkelen] (2025). Gas-Phase Electrocatalytic CO2 Reduction on Pd-Embedded UiO-67 Metal–Organic Framework Precatalysts Under Varying Relative Humidity Conditions. ChemSusChem. ISSN 1864-5631. s. 1–31. doi: 10.1002/cssc.202501929. Fulltekst i vitenarkiv Vis sammendrag

  Electrocatalytic CO2 reduction (ECO2R) to high-value chemicals is a promising method to upcycle emitted CO2, but it is also a fascinating scientific challenge. Catalyst materials, as well as cell configurations, play a pivotal role in the efficacy and efficiency of the ECO2R reaction, which also dictates reaction pathways and product selectivity. In this work, we employ the isotopological Zr- and Ce-based UiO-67 metal–organic frameworks (MOFs) that contain Pd species in a zero-gap gas diffusion cathode electrode configuration, where the water content, i.e., relative humidity (RH) level, in the CO2 gas stream can be varied. We show that only UiO-67-based MOFs containing Pd embedded in their pores can produce syngas, while the product selectivity can be controlled by varying the RH levels in the gas stream. The pristine MOFs (precatalysts) undergo chemical and structural transformation during the ECO2R reaction, forming the active catalysts toward CO2 electroreduction to syngas. Our work highlights the effect of water content on the selectivity during ECO2R, but also the need for predictive catalyst design for effective electroreduction of CO2 to high-value chemicals.

• Petlund, Henrik; Pokle, Anuj & Chatzitakis, Athanasios (2025). Suppression of surface amorphization during oxygen evolution reaction in A-site deficient perovskite oxides. Journal of Physics: Energy. 7(2). doi: 10.1088/2515-7655/adb2c0. Fulltekst i vitenarkiv Vis sammendrag

  Surface restructuring and the formation of amorphous layers during the initial stages of the oxygen evolution reaction (OER) is a common phenomenon in perovskite-based catalysts. It has also been observed that catalysts following the lattice oxygen mechanism (LOM) are prone to amorphization as the rates of lattice oxygen evolution and oxygen vacancy replenishment are not equal. This is accompanied by a significant A-site cation loss in the electrolyte, ultimately leading to the collapse of the crystalline phase and the appearance of an amorphous catalytic surface of a thickness of around 10 nm. Typically, the originally crystalline material is termed as precatalyst. In this work, we hypothesize that A-site deficient perovskite precatalysts of the family of BaxGdyLazCo2O3-δ (BGLCxyz), which operate under LOM, will have a reduced degree or no surface amorphization under OER conditions in alkaline media. For this reason, A-site deficient BGLC587 with a 20% deficiency is synthesized to validate our main hypothesis. Furthermore, thermal reduction of the A-site deficient BGLC587 precatalyst is expected, to form embedded nanoparticles on its surface through the process of exsolution, thus inducing higher surface area and improved electrocatalytic activity, while still suppressing surface amorphization.

• Petlund, Henrik; Faid, Alaa Yahia; Zhu, Junjie; Pokle, Anuj; Norby, Truls & Sunde, Svein [Vis alle 7 forfattere av denne artikkelen] (2024). Iron and Nickel Substituted Perovskite Cobaltites for Sustainable Oxygen Evolving Anodes in Alkaline Environment. ChemSusChem. ISSN 1864-5631. doi: 10.1002/cssc.202401403. Fulltekst i vitenarkiv Vis sammendrag

  Perovskite oxides have great flexibility in their elemental composition, which is accompanied by large adjustability in their electronic properties. Herein, we synthesized twelve perovskite oxide-based catalysts for the oxygen evolution reaction (OER) in alkaline media. The catalysts are based on the parent oxide perovskite Ba0.5Gd0.8La0.7Co2O6-δ (BGLC587) and are synthesized through the sol-gel citrate synthesis route. To reduce the demand on cobalt (Co), but also increase the intrinsic catalytic activity of BGLC587 for the OER, we substitute Co on the B-site with certain amounts of Fe and Ni, synthesizing catalysts of the general formula Ba0.5Gd0.8La0.7Co2-x-yFexNiyO6-δ. A plethora of physicochemical and electrochemical methods suggest that an Fe content between 30 % and 70 % increases the intrinsic catalytic activity of BGLC587, while Tafel slopes in combination with in-situ Raman spectroscopy suggest the rate determining step is likely a proton-exchange reaction, progressing possibly through the lattice oxygen mechanism (LOM). We apply one of the optimized, Co-substituted perovskites in a monolithic, photovoltaic (PV)-driven electrolysis cell and we achieve an initial solar-to-hydrogen (STH) conversion efficiency of 10.5 % under one sun solar simulated illumination.

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• Petlund, Henrik; Geo, Sarah; Velluva, Abhijai; Pokle, Anuj & Chatzitakis, Athanasios (2025). nanoGe - MATSUSFall25 - The dual role of A-site deficiency in perovskite oxides: Exsolution of metal nanoparticles and suppression of surface amorphization. Fulltekst i vitenarkiv Vis sammendrag

  Catalysts enable important chemical transformations for industrial applications, as well as for emerging technologies for the decarbonization of our societies, such as water electrolysis and the production of green hydrogen. Very often, catalysts experience structural and compositional changes during operating conditions, most notably the oxygen evolution reaction (OER), that hinder their ratio...

• Petlund, Henrik; Pokle, Anuj; Norby, Truls & Chatzitakis, Athanasios (2025). Front Cover: Iron and Nickel Substituted Perovskite Cobaltites for Sustainable Oxygen Evolving Anodes in Alkaline Environment (ChemSusChem 6/2025). ChemSusChem. ISSN 1864-5631. doi: 10.1002/cssc.202580601. Fulltekst i vitenarkiv

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