Amir Masoud Dayaghi

• Talic, Belma; Dayaghi, Amir Masoud; Singh, Kalpana; Stefan, Elena; Sunding, Martin Fleissner & Malerød-Fjeld, Harald [Show all 7 contributors for this article] (2026). Chemical stability of BaZr1−xCexO3−δ-based electrolytes in pressurized CO2. Solid State Ionics. ISSN 0167-2738. 444, p. 1–7. doi: 10.1016/j.ssi.2026.117251. Full text in Research Archive Show summary

  Acceptor doped barium cerates and zirconates are attractive electrolyte materials for use in proton ceramic electrochemical cells. However, the long-term stability of these materials may be compromised by their tendency to react with CO2. In this work, the chemical stability of the Zr-rich electrolyte materials BaZr0.8Ce0.1Y0.1O3−δ (BZCY81) and BaZr0.9Y0.1O3−δ (BZY10), and the Ce-rich electrolyte materials BaZr0.4Ce0.4Y0.2O3−δ (BZCY442) and BaZr0.4Ce0.4Y0.1Yb0.1O3−δ (BZCYYb4411) are studied in 10 bar CO2 at 500 °C for 150 h. X-ray diffraction and scanning electron microscopy analysis showed BaCO3 formation for the Ce-rich electrolytes, while the Zr-rich electrolytes showed excellent stability. The chemical stability of the Zr-rich electrolytes was further confirmed under 10% H2 in CO2 (10 bar) at 800 °C. Addition of NiO sintering aid to the Ce-rich electrolytes did not have a major impact on the chemical stability although the amount of BaCO3 formation appeared to be slightly reduced.

• Jiang, Lulu; Toyoura, Kazuaki; Dayaghi, Amir Masoud; Chen, Huaican; Yuan, Bao & Yin, Wen [Show all 10 contributors for this article] (2025). Fast Oxide Ion Conduction in Ba3MoNbO8.5 Enhanced by Acceptor Substitution and Dehydration. Journal of the American Chemical Society. ISSN 0002-7863. 147(50), p. 46515–46515. doi: 10.1021/jacs.5c17115. Full text in Research Archive Show summary

  Ba3MoNbO8.5 (BMN) exhibits high O2– conductivity by disordered partially occupied O2 + O3 sites. Hydration decreases, and certain dopants increase the conductivity, and we present a novel model for defects and transport over two sites that rationalizes these behaviors. A broad experimental and computational study shows that hydration increases the activation energy of migration by immobile protons and fills the O2 + O3 plane. Acceptor substitution reverses this by emptying the O2 + O3 plane and spreading protons, and 5 at % Y substitution yields a bulk oxide ion conductivity exceeding 10 mS·cm–1 at 650 °C and effectively suppresses the effect of humidity. The effects of hydration and acceptor substitution on the grain boundary (GB) resistance suggest a positively charged GB core by vacancy and proton accumulation with adjacent space charge regions with higher filling and activation energy and that doping and GB engineering may pave the way for operando utilization of Ba3MoNbO8.5-related oxide ion conductors.

• Dayaghi, Amir Masoud; Almar, Laura; Escolástico, Sonia; Jiang, Bo; Carvalho, Patricia Almeida & Alfaro, Jose Manuel Serra [Show all 8 contributors for this article] (2025). On the cation distribution in acceptor doped Ba(Zr,Ce)O3 (Zr,Ce)O2 co-ionic composite electrolytes. Journal of Materials Chemistry A. ISSN 2050-7488. 13(39), p. 33528–33540. doi: 10.1039/d5ta02711j. Full text in Research Archive Show summary

  Composite co-ionic ceramic electrolytes that combine proton and oxide ion conductors hold potential for co-electrolysis of CO2 and H2O for syngas production due to flexible control of the transport numbers of the two charge carriers. Contrary to purely oxide ion co-electrolysis, co-ionic co-electrolysis embodies the supply of CO2 and H2O separately to the negative and positive electrodes, respectively. This study focuses on the development of a chemically stable co-ionic composite electrolyte of an acceptor-doped Ba(Zr,Ce)O3 proton conducting perovskite phase and an acceptor-doped (Ce,Zr)O2 oxide ion conducting fluorite phase, annealed at temperatures between 800 and 1600 °C. Comprehensive evaluations of the composites' microstructure, hydration, and conductivity were performed, revealing that annealing temperature and cation selection significantly impact the properties and performance of co-ionic electrolytes. Higher annealing temperatures drive cation redistribution, with the perovskite phase becoming zirconium-rich at its B-site and depleted in acceptor dopants, resulting in diminished hydration and protonic conductivity. Herein, we show that composites pairing cerium-rich fluorite phases (e.g., Ce0.8Gd0.2O1.9, CGO20, or Ce0.8Y0.2O1.9, CYO20) display markedly improved performance. The BaCe0.8Y0.2O2.9 (BCY20)–CYO20 system (1 : 1 weight ratio) achieved the highest conductivity (σ = 0.01 Scm−1 at 650 °C in wet Ar), establishing itself as a promising candidate for co-ionic electrolyte applications in solid oxide electrochemical cells.

• Ismail, Sara Adeeba; Toyoura, Kazuaki; Jiang, Lulu; Dayaghi, Amir Masoud; Guo, Hui & Avdeev, Maxim [Show all 11 contributors for this article] (2025). Ba7Nb4MoO20: A Proton or Oxide Ion Conductor? Journal of the American Chemical Society. ISSN 0002-7863. 147(28), p. 24774–24784. doi: 10.1021/jacs.5c06467. Full text in Research Archive Show summary

  Ba7Nb4MoO20 is a recently emerging fast oxide ion conductor, attracting increasing attention. It was reported to also show proton conduction in a humid atmosphere, which is, however, opposite to the results in this work. Theoretical calculations indicate that protons can hardly move, being stabilized in the perovskite blocks or trapped in the palmierite layers, which is in line with the experimental evidence of almost no H2O/D2O isotope effect and a negligibly small transport number of protons by EMF measurements up to 800 °C. It is thereby clear that Ba7Nb4MoO20 is almost a pure oxide ion conductor even though it can be hydrated upon exposure to moisture. The hydration in fact stabilizes interstitial oxide ions (O5 site) in the palmierite layers by forming Nb2O9H units, leading to reduced bulk conductivity in the pristine and slightly Nb-rich compositions at <400 °C. However, by heating up over 400 °C, the bulk conductivity in the wet atmosphere surpasses that in the dry one, benefitting from an injection of protons into the perovskite blocks to release free O5 ions for oxide ion conduction, indicating that hydration may provide extra oxide ions to enhance the oxide ion conduction.

• Lu, Yang; Sednev-Lugovets, Anton; Carvalho, Patricia Almeida; Guzik, Matylda N.; Dayaghi, Amir Masoud & Dunkel, Kristina G [Show all 9 contributors for this article] (2025). Dypingite as a hydration series with reversible change of H2O content. American Mineralogist. ISSN 0003-004X. 111(5), p. 746–757. doi: 10.2138/am-2024-9603. Full text in Research Archive Show summary

  Dypingite has recently been found to have promising applications in material and environmental sciences. However, its exploitation is limited due to its ambiguous identification via powder X-ray diffraction (PXRD), which is caused by the occurrence of several phases with similar structures and PXRD patterns to that of dypingite. Multiple dypingite-like phases with partially overlapping X-ray diffraction traces appear to exist. To better understand dypingite, we studied samples from Dypingdal and Feragen Ultramafic Body, Norway. Dypingite sensu stricto (s.s.), several dypingite-like phases, and hydromagnesite were identified by PXRD. Three regions of 2θ (CuKα) were recognized where diffraction peaks are readily observed to transition between dypingite s.s., dypingite-like phases, and hydromagnesite. The position of the peak at around 8.5° 2θ varies with the H2O contents measured by the thermogravimetric and Fourier transform infrared analyses, suggesting that structural and compositional characteristics of dypingite-like phases form a continuum between dypingite s.s. and hydromagnesite. Humidity incubation experiments at room temperature indicated a reversible change of H2O content between dypingite s.s. and dypingite-like phases. High humidity conditions increased H2O contents of dypingite-like phases to dypingite s.s., whereas low humidity conditions reversed the direction towards hydromagnesite, but without complete reaction. Such transition behavior suggests that the structures of dypingite s.s. and the dypingite-like phases are very similar, probably identical in building unit topology but with different degrees of hydration, whereas the structure of hydromagnesite is less closely related. This study draws attention to the sample processing on dypingite hydration series, contributes to the applications of this series in CO2 sequestration, and gives suggestions to the refinement of structures of dypingite and dypingite-like phases.

• Zheng, Haoyu; Sata, Noriko; Han, Feng; Dayaghi, Amir Masoud; Iguchi, Fumitada & Develos-Bagarinao, Katherine [Show all 9 contributors for this article] (2024). Hydrogen Production with a Protonic Ceramic Membrane Reactor on Porous Fe-Cr Alloy. ACS Energy Letters. 9(8), p. 3962–3969. doi: 10.1021/acsenergylett.4c01173. Full text in Research Archive Show summary

  A metal supported design is desirable for ceramic electrochemical cells because of its robustness. Yet, a strong alkaline character and a refractory nature of the electrolyte material make it challenging to densify onto a steel component. Here we show a metal supported protonic ceramic cell (MS-PCC) concept enabling ∼90% ceramic material savings compared to traditional cell design. The manufacturing route combines wet ceramic processing with sintering and thin film deposition at temperatures below 1000 °C. The critical diffusive elements were sufficiently confined, and the volume variation of the different functional layers was limited to maintain the integrity of the thin film electrolyte. Applied to steam electrolysis for hydrogen production, the MS-PCC enabled a current density of about −0.84 A cm–2 at 600 °C at a terminal voltage of 1.3 V. This concept offers incomparable perspectives for scale-up and opens up a broad range of applications for hydrogen or Power-to-X applications.

• Quina, Imanol; Almar, Laura; Catalán-Martínez, David; Dayaghi, Amir Masoud; Martínez, Agustin & Norby, Truls [Show all 8 contributors for this article] (2023). Direct electrocatalytic CO<inf>2</inf> reduction in a pressurized tubular protonic membrane reactor. Chem Catalysis. ISSN 2667-1107. 3(10). doi: 10.1016/j.checat.2023.100766. Full text in Research Archive
• Luo, Yadan; Li, Ying; Huang, Wenlong; Dayaghi, Amir Masoud; Zhou, Gaopeng & Ding, Yushi [Show all 8 contributors for this article] (2023). Chemical stability and electrical properties of Ba1−xCaxCe0.8Gd0.2O3−δ (0 ≤ x ≤ 0.06) proton conductor. International Journal of Hydrogen Energy. ISSN 0360-3199. 48(15), p. 5656–5667. doi: 10.1016/j.ijhydene.2022.11.072. Full text in Research Archive
• Dayaghi, Amir Masoud; Polfus, Jonathan M.; Strandbakke, Ragnar; Pokle, Anuj; Almar, Laura & Escolastico, Sonia [Show all 10 contributors for this article] (2023). Effects of sintering additives on defect chemistry and hydration of BaZr0.4Ce0.4(Y,Yb)0.2O3−δ proton conducting electrolytes. Solid State Ionics. ISSN 0167-2738. 401. doi: 10.1016/j.ssi.2023.116355. Full text in Research Archive
• Sata, Noriko; Han, Feng; Zheng, Haoyu; Dayaghi, Amir Masoud; Norby, Truls & Stange, Marit Synnøve Sæverud [Show all 8 contributors for this article] (2021). Development of Proton Conducting Ceramic Cells in Metal Supported Architecture. ECS Transactions. ISSN 1938-5862. 103(1), p. 1779–1789. doi: 10.1149/10301.1779ecst. Full text in Research Archive Show summary

  Metal-Supported (MS) architecture offers various advantages over state-of-the-art ceramic supported SOCs, such as high tolerance towards thermal/redox cycling that are key features for flexible and reliable operation in high temperature fuel cell and electrolysis applications. Our target is to develop Proton-conducting Ceramic Cells (PCC) in MS architecture, of which combination can provide potentially high performances, mechanical stability, and flexibility for wide range of electrochemical applications. The key challenge in the development of MS-PCC is to find a feasible process to fabricate gas-tight electrolyte on the porous metal substrate without degrading the metal support and the electrolyte. Our strategy is implementing multilayers combining wet chemical processes below 1000°C for the functional electrode and dry Physical Vapor Deposition (PVD) techniques below 800°C for the gas-tight electrolyte coating. In this paper, we present our recent results in the development of MS-PCC half cells. The materials selection for MS and PCC components, functional layer processing, and electrolyte layer deposition techniques are discussed.

• Dayaghi, Amir Masoud; Haugsrud, Reidar; Stange, Marit Synnøve Sæverud; Larring, Yngve; Strandbakke, Ragnar & Norby, Truls Eivind (2021). Increasing the thermal expansion of proton conducting Y-doped BaZrO3 by Sr and Ce substitution. Solid State Ionics. ISSN 0167-2738. 359. doi: 10.1016/j.ssi.2020.115534. Full text in Research Archive Show summary

  Proton conducting oxide electrolytes find potential application in proton ceramic fuel cells and electrolyzers operating at intermediate temperatures, e.g. 400–600 °C. However, state-of-the-art proton conducting ceramics based on Y-doped BaZrO3 (BZY) have lower thermal expansion coefficient (TEC) than most commonly applied or conceived supporting electrode structures, making the assembly vulnerable to degradation due to cracks or spallation. We have increased the TEC of 20 mol% Y-doped BZY (BZY20) by partially substituting Ba and Zr with Sr and Ce, respectively, to levels which still maintain the cubic structure and sufficiently minor n-type conduction; (Ba0.85Sr0.15)(Zr0.7Ce0.1Y0.2)O2.9 (BSZCY151020). High temperature XRD shows that this material has a cubic structure (space group ) in the temperature range of 25–1150 °C and a linear TEC of ~10 × 10−6 K−1, as compared to the ~8 × 10−6 K−1 for BZY. It exhibited a DC conductivity of ~5 mS cm−1 at 600 °C in wet H2. This electrolyte with increased TEC may find application in proton ceramic electrochemical cells in general and metal supported ones in particular.

• Han, Feng; Zhou, Xingping; Dayaghi, Amir Masoud; Norby, Truls Eivind; Stange, Marit Synnøve Sæverud & Sata, Noriko [Show all 7 contributors for this article] (2019). Development of Metal Supported Cells Using BaZrO3-Based Proton Conducting Ceramics. ECS Transactions. ISSN 1938-5862. 91(1), p. 1035–1045. doi: 10.1149/09101.1035ecst. Full text in Research Archive
• Stange, Marit Synnøve Sæverud; Dayaghi, Amir Masoud; Denonville, Christelle; Larring, Yngve; Rørvik, Per Martin & Haugsrud, Reidar [Show all 7 contributors for this article] (2019). Fabrication of metal-supported proton-conducting electrolysers with thin film Sr- And Ce-doped BZY electrolyte. ECS Transactions. ISSN 1938-5862. 91(1), p. 941–949. doi: 10.1149/09101.0941ecst. Full text in Research Archive Show summary

  n this work, we present fabrication and initial testing of metal-supported proton ceramic electrolyser (MS-PCEC) single cells with a thin electrolyte. Plansee ITM porous metal is used as metal support. Spray-coating is used to deposit a conducting layer of La1-xSrxTi1-yNiyO3-δ (LSTN) which is used for low temperature (600-800 °C) deposition of a gas-tight, thin-film layer (~2 μm) of electrolyte by pulsed laser deposition (PLD). Post-annealing of the electrolyte is evaluated to improve its performance. In order to have a smaller thermal expansion coefficient (TEC) mismatch towards LSTN (~10-11 × 10-6 K-1), we developed a new Sr- and Ce-doped proton-conducting electrolyte, yielding a larger TEC (~10-11 × 10-6 K-1) compared to BZY (~8 × 10-6 K-1). The cell with Pt as air electrode shows acceptable open circuit voltage and low overpotentials at 600 °C, demonstrating the potential of developing the first working MS-PCEC.

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• Geo, Sarah; Pokle, Anuj; Velluva, Abhijai; Dayaghi, Amir Masoud & Chatzitakis, Athanasios (2025). Suppressing surface amorphization in BSCF-based perovskites through A-site deficiency for use as anodes in water electrolysis. Full text in Research Archive Show summary

  The development of efficient and stable anodes for water electrolysis is critical to advancing sustainable hydrogen production. Among perovskite oxides, BSCF82 (Ba₀.₅Sr₀.₅Co₀.₈Fe₀.₂O₃-δ) has emerged as a promising candidate due to its favourable balance of electronic conductivity, oxygen mobility, and catalytic activity. However, BSCF82 suffers from serious degradation during the oxygen evolution reaction (OER) process due to surface amorphization caused by the leeching of A-site ions (Ba²⁺ and Sr²⁺)​[1]​. Previously, we showed that A-site deficiency in Ba0.5Gd0.8La0.7Co2O6 can suppress it surface amorphization during OER activity and in the present study, we generalize this observation by employing a similar strategy in BSCF82​[2]​. By creating controlled A-site vacancies in the Ba₀.₅-xSr₀.₅-xCo₀.₈Fe₀.₂O₃-δ perovskite structure, we achieved improvement in its structural stability under OER conditions in 1 M KOH. High-resolution transmission electron microscopy revealed that A-site deficient compositions exhibited reduced surface amorphization and preserved crystalline surface structures after electrochemical testing in 1 M KOH. This work provides new insights into mitigating surface amorphization in perovskite catalysts through defect engineering and presents a promising strategy for developing durable electrocatalysts for renewable energy applications. Acknowledgements: This work has received financial support from the European Union HORIZON Research and Innovation Actions under grant agreement ID 101122323 (REFINE).

• Stefan, Elena; Fontaine, Marie-Laure; Dayaghi, Amir Masoud; Vigen, Camilla Kaori; Vøllestad, Einar & Almar, Laura [Show all 11 contributors for this article] (2023). Ceramic membrane reactors for the electrocatalytic conversion of CO2 into chemical energy carriers. Full text in Research Archive
• Stange, Marit Synnøve Sæverud; Denonville, Christelle; Stefan, Elena; Dayaghi, Amir Masoud; Larring, Yngve & Rørvik, Per Martin [Show all 9 contributors for this article] (2022). Fabrication and testing of thin-film based metal-supported proton ceramic electrochemical cells. Full text in Research Archive
• Dayaghi, Amir Masoud; Polfus, Jonathan; Strandbakke, Ragnar; Vøllestad, Einar; Haugsrud, Reidar & Norby, Truls (2022). Effects of NiO, ZnO and CuO sintering additives on the hydration of BaZr0.4Ce0.4(Y,Yb)0.2O3-δ proton conducting electrolytes. Full text in Research Archive
• Talic, Belma; Dayaghi, Amir Masoud; Vøllestad, Einar; Stefan, Elena; Sunding, Martin Fleissner & Polfus, Jonathan (2022). Chemical Stability of Proton Conducting BaZr1-xCexO3-Based Electrolytes in Pressurized CO2-Containing Atmospheres. Full text in Research Archive Show summary

  Acceptor doped barium cerates and zirconates are attractive electrolyte materials for use in various proton ceramic electrochemical devices such as fuel cells and hydrogen pumps. However, the long-term durability of these materials may be challenged by poor chemical stability in CO2-containing atmospheres. In this work, the chemical stability of the electrolyte material BaZr0.8Ce0.1Y0.1O3 (BZCY81) is studied in CO2 and CO2-H2. Dense pellets prepared by sintering with NiO as a sintering aid were exposed to up to 10 bar CO2(-H2) for up to 150 h at elevated temperatures (400-800°C). After exposure, the pellet surface was analyzed by grazing incidence X-ray diffraction (XRD), scanning electrode microscopy (SEM), and X-ray photoelectron spectroscopy (XPS) to search for BaCO3 formation. Overall, the electrolyte material displayed excellent stability towards CO2. A small increase in apparent BaCO3 concentration on the pellet surface was only detected by XPS for samples aged in CO2 and CO2-H2 at 800 °C. However, BaCO3 was not visible by XRD and SEM-EDS, indicating that the reactivity is limited to a nm-thick region of the electrolyte surface. The impact of processing conditions such as sintering temperature and use of NiO sintering aid on the electrolyte stability will be discussed.

• Stefan, Elena; Fontaine, Marie-Laure; Dayaghi, Amir Masoud; Vigen, Camilla Kaori; Vøllestad, Einar & Almar, Laura [Show all 11 contributors for this article] (2021). Development of protonic membrane reactors for the electrocatalytic conversion of CO2 into chemical energy carriers. Full text in Research Archive
• Stange, Marit Synnøve Sæverud; Stefan, Elena; Dayaghi, Amir Masoud; Denonville, Christelle; Larring, Yngve & Rørvik, Per Martin [Show all 8 contributors for this article] (2021). Pulsed Laser Deposition of Electrolytes for Metal-Supported Proton-Conducting Electrolysis Cells. Full text in Research Archive
• Norby, Truls; Dayaghi, Amir Masoud; Storhaug, Sjur; Chen, Henry; Haugsrud, Reidar & Stange, Marit Synnøve Sæverud [Show all 9 contributors for this article] (2021). BSZCY151020: A proton ceramic electrolyte with increased TEC for planar applications. Full text in Research Archive
• Stange, Marit Synnøve Sæverud; Stefan, Elena; Denonville, Christelle; Dayaghi, Amir Masoud; Larring, Yngve & Rørvik, Per Martin [Show all 11 contributors for this article] (2021). Processing route for Metal Supported Proton Conducting Ceramic Cells. Full text in Research Archive
• Stange, Marit Synnøve Sæverud; Dayaghi, Amir Masoud; Denonville, Christelle; Larring, Yngve; Rørvik, Per Martin & Haugsrud, Reidar [Show all 7 contributors for this article] (2019). Key challenges in fabrication of metal-supported thin film proton conducting electrolyser cells. Full text in Research Archive
• Stange, Marit Synnøve Sæverud; Dayaghi, Amir Masoud; Denonville, Christelle; Larring, Yngve; Rørvik, Per Martin & Haugsrud, Reidar [Show all 7 contributors for this article] (2019). Fabrication of Metal-Supported Proton-Conducting Electrolysers with Thin Film Sr- and Ce-Doped BZY Electrolyte. Full text in Research Archive
• sata, noriko; han, feng; costa, remi; Zhou, Xingping; Stange, Marit Synnøve Sæverud & Dayaghi, Amir Masoud [Show all 7 contributors for this article] (2019). Development of Metal Supported Cells Using BaZrO3-Based Proton Conducting Ceramics. Full text in Research Archive
• Dayaghi, Amir Masoud; Stange, Marit Synnøve Sæverud; Denonville, Christelle; Larring, Yngve; Rørvik, Per Martin & Haugsrud, Reidar [Show all 7 contributors for this article] (2019). Thin-film electrolyte with TEC optimized for metal-supported proton ceramic electrochemical cell. Full text in Research Archive
• Stange, Marit Synnøve Sæverud; Dayaghi, Amir Masoud; Denonville, Christelle; Rørvik, Per Martin; Larring, Yngve & Norby, Truls Eivind (2018). Fabrication of Metal Supported Protonic Ceramic Electrolyser Cells (PCEC). Full text in Research Archive
• Dayaghi, Amir Masoud; Stange, Marit Synnøve Sæverud; Denonville, Christelle; Larring, Yngve; Rørvik, Per Martin & Norby, Truls Eivind (2018). Key challenges in fabrication of metal-supported proton conducting electrolyser cells. Full text in Research Archive
• Chen, Henry; Norby, Truls; Haugsrud, Reidar & Dayaghi, Amir Masoud (2022). Sintering Behavior and Conductivity of (Ba0.85Sr0.15)(Zr0.7Ce0.1Y0.2)O3-δ Doped with ZnO as Sintering Aid. Universitetet i Oslo. Full text in Research Archive

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