Thomas Schmidt

Last Name

Schmidt

First Name

Thomas

ORCID

0000-0002-1636-367X

Organisational unit

03910 - Schmidt, Thomas J. / Schmidt, Thomas J.

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Publications 1 - 10 of 316

Design and Synthesis of Ir/Ru Pyrochlore Catalysts for the Oxygen Evolution Reaction Based on Their Bulk Thermodynamic Properties
Abbott, Daniel F.; Pittkowski, Rebecca K.; Macounová, Kateřina; et al. (2019)
ACS Applied Materials & Interfaces
On the water transport mechanism through the microporous layers of operando polymer electrolyte fuel cells probed directly by X-ray tomographic microscopy
Chen, Yen-Chun; Dörenkamp, Tim; Csoklich, Christoph; et al. (2023)
Energy Advances
Product water transport via the microporous layer (MPL) and gas diffusion layer (GDL) substrate during polymer electrolyte fuel cell (PEFC) operation was directly and quantitatively observed by X-ray tomographic microscopy (XTM). The liquid water distribution in two types of MPLs with different pore size distributions (PSDs) was characterized as a function of the inlet gas relative humidity (RH) and current density under humid operating conditions at 45(degrees)C. During the first minute of PEFC operation, liquid water mainly accumulated at the catalyst layer (CL)/MPL interface and in the GDL substrate close to the flow fields. Furthermore, under all tested conditions, saturation in the MPL was low (<25%), whereas under the rib, the saturation in the GDL was up to ca. 70%. Based on these XTM results, it is confirmed that in the high porosity MPLs, vapor transport was non-negligible even at high humidity conditions. Therefore, on top of the widely discussed MPL pore size and its distribution, it is proposed that the lower thermal conductivity from the high porosity of MPLs can also be a main cause of promoted vapor transport, reducing water saturation near the CL.
Bimetallic Aerogels: High-Performance Electrocatalysts for the Oxygen Reduction Reaction
Liu, W.; Rodriguez, P.; Borchardt, L.; et al. (2013)
Angewandte Chemie. International Edition
Impacts of digitalization and societal changes on energy transition: a novel socio-techno-economic energy system model
Stermieri, Lidia; Kober, Tom; McKenna, Russell; et al. (2023)
Energy Strategy Reviews
The increased diffusion of information and communication technologies (ICTs) impacts daily life and economic growth. It introduces new social practices for households and business models for companies that influence society and energy infrastructure development. A framework capable of quantifying and analyzing the impact of digitalization on achieving energy and climate targets, with a focus on behavioral changes induced by ICT, is currently lacking. In this paper, a new framework is developed that is technology-rich and captures the preferences and behaviors of households and firms in the energy system to assess sustainable energy system configurations that are technically and socially feasible. The framework is designed and demonstrated for Switzerland. We find, for example, that teleworking in Switzerland reduces commuting demand by 10%, and the savings in transport expenses can favor the investment in efficient and clean residential technologies to compensate for the increased residential energy demand due to working at home. This manuscript contributes to the growing literature of suitable frameworks and case studies to account for the co-evolution of society and energy systems in achieving the transition to low-carbon economies.
Direct evidence of cobalt oxyhydroxide formation on a La0.2Sr0.8CoO3 perovskite water splitting catalyst
Boucly, Anthony; Artiglia, Luca; Fabbri, Emiliana; et al. (2022)
Journal of Materials Chemistry A
Understanding the mechanism of the oxygen evolution reaction (OER) on perovskite materials is of great interest for the development of more active catalysts. Despite a lot of literature reports, the complexity of catalytic systems and scarce in situ and operando surface sensitive spectroscopic tools render the detection of active sites and the understanding of reaction mechanisms challenging. Here, we carried out and compared in situ and ex situ ambient pressure X-ray photoelectron spectroscopy experiments on a La0.2Sr0.8CoO3-delta perovskite OER catalyst. The experimental results show that segregated surface strontium, which is present in the as prepared sample, is leached into the electrolyte after immersion, leading to surface cobalt active site enrichment. Such a cobalt-enriched oxide surface evolves into a new phase, whose spectral feature is detected in situ and after the OER. With the help of theoretical simulations, such a species is assigned to cobalt oxyhydroxide, providing direct evidence of its formation and surface segregation during the oxygen evolution reaction.
Superior Bifunctional Electrocatalytic Activity of Ba0.5Sr0.5Co0.8Fe0.2O3-/Carbon Composite Electrodes: Insight into the Local Electronic Structure
Fabbri, Emiliana; Nachtegaal, Maarten; Cheng, Xi; et al. (2015)
Advanced Energy Materials
Unsupported Pt3Ni Aerogels as Corrosion Resistant PEFC Anode Catalysts under Gross Fuel Starvation Conditions
Henning, Sebastian; Shimizu, Ryo; Herranz, Juan; et al. (2018)
Journal of the Electrochemical Society
Mitigating catalyst corrosion is crucial for the commercial success of polymer electrolyte fuel cells (PEFCs). Novel catalysts that can withstand the harsh conditions in case of gross fuel (i.e. H2) starvation events at the PEFC anode are needed to increase the fuel cell stack's service life and to meet the durability targets set for automotive applications. To make progress in this respect, we have tested an unsupported, bimetallic Pt3Ni alloy (aerogel) catalyst at the PEFC anode and subjected it to a stress test that mimics the high potentials (≥ 1.5 V vs. the reversible hydrogen electrode) encountered upon fuel starvation. In contrast to commercial carbon-supported platinum catalysts (Pt/C), the Pt3Ni aerogel displays excellent durability and performance retention in end-of-life fuel cell polarization curves. Additionally, the aerogel catalyst shows ≈35% higher surface-specific activity for the hydrogen oxidation/evolution reaction than Pt/C. These results highlight the great potential of using novel unsupported catalysts at the anode of PEFCs.
Potentiostatic lithium plating as a fast method for electrolyte evaluation in lithium metal batteries
Winter, Eric; Schmidt, Thomas; Trabesinger, Sigita (2023)
Electrochimica Acta
One of the most crucial factors to enable metallic lithium anodes is having an electrolyte that allows stable and safe battery cycling, however, the commonly used carbonate electrolytes typically perform poorly, highlighting the need for the development of new electrolyte compositions. Evaluating potential electrolyte candidates is typically a lengthy procedure that does need time-consuming long-term cycling experiments. To speed this process up, we have investigated potentiostatic lithium plating, inspired from hydrogen-pumping performed for fuel cell performance evaluation, as a potential method for fast electrolyte suitability investigation. First, scanning electron microscopy was used to establish a link between lithium surface coverage and measured current response in a model carbonate electrolyte. Afterwards, a selection of carbonate and ether electrolytes was used for validation of our testing procedure, showing that individual, characteristic patterns can be distinguished. Apart from giving an insight into Li transport in each electrolyte, a correlation to physical electrolyte properties can be found. Consequently, our findings may be a first step towards using potentiostatic plating as a fast, easy and high-throughput method to investigate suitability of new electrolyte formulations for lithium metal batteries and beyond.
Boosting Pt oxygen reduction reaction activity by tuning the tin oxide support
Fabbri, Emiliana; Rabis, Annett; Chino, Yuji; et al. (2017)
Electrochemistry Communications
Oxygen evolution reaction activity and underlying mechanism of perovskite electrocatalysts at different pH
Kim, Bae-Jung; Fabbri, Emiliana; Borlaf, Mario; et al. (2021)
Materials Advances
The members of the perovskite oxide family have been vastly explored for their potential as active electrocatalysts for an efficient anodic reaction (i.e. the oxygen evolution reaction, OER) of the water splitting process. Therefore, restless effort has been invested in the development of perovskite oxides as efficient OER catalysts, while the OER mechanism is still in veil. The rational development of perovskite catalysts for practical water electrolysis is left on hold until the full comprehension of the underlying mechanism is established under real operation conditions. Up to date, primarily two different OER mechanisms - conventional and lattice oxygen evolution - have been conjectured where the former follows a reversible route while the latter leads to irreversible changes. In this present study, we present evidence which suggests that perovskite catalysts follow both mechanisms concomitantly while one is preferentially selected based on their thermodynamic and kinetic natures dependent on pH.

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