Jan P. Hofmann
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View article: Nanocrystalline Ordered Mesoporous Co(OH) <sub>2</sub> and Co <sub>3</sub> O <sub>4</sub> Thin Films: Oxygen Evolution Reaction Activity from a Structural Properties Perspective
Nanocrystalline Ordered Mesoporous Co(OH) <sub>2</sub> and Co <sub>3</sub> O <sub>4</sub> Thin Films: Oxygen Evolution Reaction Activity from a Structural Properties Perspective Open
Design of nanostructured electrocatalysts is essential to improve the efficiency for driving the oxygen evolution reaction (OER) at low overpotentials. Mesoporous cobalt‐based thin films are prepared by dip‐coating and soft‐templating usin…
View article: Sulfophenylated centimeter-sized graphene membrane in a direct methanol fuel cell
Sulfophenylated centimeter-sized graphene membrane in a direct methanol fuel cell Open
An ideal proton exchange membrane should only allow protons to pass and remain impermeable to fuels, as required in fuel cell applications. In methanol fuel cells, high proton conductivity enables high power density, whereas methanol cross…
View article: Redox Chemistry of LiCoO$_2$, LiNiO$_2$, and LiNi$_{1/3}$Mn$_{1/3}$Co$_{1/3}$O$_2$ Cathodes: Deduced via XPS, DFT+DMFT, and Charge Transfer Multiplet Simulations
Redox Chemistry of LiCoO$_2$, LiNiO$_2$, and LiNi$_{1/3}$Mn$_{1/3}$Co$_{1/3}$O$_2$ Cathodes: Deduced via XPS, DFT+DMFT, and Charge Transfer Multiplet Simulations Open
Understanding the evolution of the physicochemical bulk properties during the Li deintercalation (charging) process is critical for optimizing battery cathode materials. In this study, we combine X-ray photoelectron spectroscopy (XPS), den…
View article: Chemical Potential of Iron in Systems of Low Dimensionality
Chemical Potential of Iron in Systems of Low Dimensionality Open
The influence of particle size on heterogeneous equilibria is investigated using Fe clusters as an example. Considering a thermodynamic cycle, the change in free enthalpy for the transfer of an Fe atom from a dispersed system to the bulk i…
View article: High Pressure H2 treatment for deep cleaning of Fe single crystals
High Pressure H2 treatment for deep cleaning of Fe single crystals Open
Iron single crystals Fe(100), Fe(111) and Fe(110) were reduced with a high-pressure autoclave H2-treatment to obtain clean surfaces. By increasing the pressure, the reduction was finished after 3 hours with temperature T = 600 °C and press…
View article: The Role of Copper‐Oxide Species in Copper‐Catalyzed Electrochemical CO<sub>2</sub> Reduction
The Role of Copper‐Oxide Species in Copper‐Catalyzed Electrochemical CO<sub>2</sub> Reduction Open
Copper catalyzes the electrochemical reduction of CO 2 (CO 2 RR) to valuable chemicals using renewable electricity. Although oxide‐derived copper (OD‐Cu) demonstrates improved CO 2 RR performance, particularly for C 2+ products, its origin…
View article: DFT-Guided Operando Raman Characterization of Ni-Based Phases Relevant to Electrochemical Systems
DFT-Guided Operando Raman Characterization of Ni-Based Phases Relevant to Electrochemical Systems Open
We present a phase-resolved investigation of Ni-based oxides and hydroxides relevant to the oxygen evolution reaction (OER), combining ground-state DFT+U calculations with operando and in situ Raman spectroscopy, supported by high-resoluti…
View article: Activation of NiFe oxide-based OER catalysts: Iron determines the growth of the catalytically active phase in NiO
Activation of NiFe oxide-based OER catalysts: Iron determines the growth of the catalytically active phase in NiO Open
Mixed nickel iron hydr-/oxides are nowadays the best performing alkaline O2 evolution electrocatalysts. It has been assumed that the activity of these catalysts is determined by surface species but that a conditioning of the bulk is necess…
View article: Enhancing Photocurrent of Bismuth Manganate Photoanodes with Nanoislands of Bismuth Oxide
Enhancing Photocurrent of Bismuth Manganate Photoanodes with Nanoislands of Bismuth Oxide Open
Photoelectrochemical (PEC) water splitting is a promising method for the energy transition. However, it is still hampered because the performance of the electrodes is too low. Herein, bismuth manganate (BMO) is investigated as a photoanode…
View article: Alloyed single-atom catalysts for electro- and photo- catalytic water splitting
Alloyed single-atom catalysts for electro- and photo- catalytic water splitting Open
Water splitting by using renewable energy to produce hydrogen and oxygen can be regarded as one of the most promising approaches for sustainable energy conversion. Developing cost-effective and high-performance water splitting catalysts pl…
View article: Benchmarking the Stability of State-of-the-Art H<sub>2</sub>O<sub>2</sub> Electrocatalysts under Acidic Conditions
Benchmarking the Stability of State-of-the-Art H<sub>2</sub>O<sub>2</sub> Electrocatalysts under Acidic Conditions Open
Electrocatalytic hydrogen peroxide (H2O2) production presents a promising alternative to conventional synthesis methods, such as the anthraquinone process. It utilizes electrocatalysts to selectively reduce oxygen through a two-electron tr…
View article: p-Type Al-Doped MoS<sub>2</sub> Nanosheet Films: Electronic and Chemical Interface Properties with Gold for Electronic Device Integration
p-Type Al-Doped MoS<sub>2</sub> Nanosheet Films: Electronic and Chemical Interface Properties with Gold for Electronic Device Integration Open
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View article: Enhancing the hydrogen tolerance of La0.6Ca0.4Co0.2Fe0.8O3– oxygen transport membranes with the substitution of 10 % Mn at the B site for plasma assisted CO2 conversion
Enhancing the hydrogen tolerance of La0.6Ca0.4Co0.2Fe0.8O3– oxygen transport membranes with the substitution of 10 % Mn at the B site for plasma assisted CO2 conversion Open
The tendency of mixed ionic electronic conducting (MIEC) materials to be highly selective towards oxygen allows for their use as oxygen transport membranes (OTMs). To be used as OTMs in plasma assisted CO2 conversion and H2 utilisation app…
View article: Voltage-dependent charge compensation mechanism and cathode electrolyte interface stability of the lithium-ion battery cathode materials LiNi0.6Mn0.2Co0.2O2, LiNi0.8Mn0.1Co0.1O2 and LiNi0.80Co0.15Al0.05O2 studied by photoelectron spectroscopy
Voltage-dependent charge compensation mechanism and cathode electrolyte interface stability of the lithium-ion battery cathode materials LiNi0.6Mn0.2Co0.2O2, LiNi0.8Mn0.1Co0.1O2 and LiNi0.80Co0.15Al0.05O2 studied by photoelectron spectroscopy Open
The wide utilization of Ni-rich oxides as a cathode material in lithium-ion batteries (LIB) for high-energy applications remains a challenge due to their unstable behavior at high state-of-charge (SOC) increasing the risk of thermal runawa…
View article: Water Dissociation on NiOOH in Alkaline Water Electrolysis Improves with Increasing Alkali Metal Cation Size
Water Dissociation on NiOOH in Alkaline Water Electrolysis Improves with Increasing Alkali Metal Cation Size Open
The activity of nickel‐based electrocatalysts toward the oxygen evolution reaction (OER) is influenced by the presence of alkali metal cations in the electrolyte. Since the underlying mechanism is not fully resolved yet, a study combining …
View article: Direct Recycling of All‐Solid‐State Batteries with a Halide Solid Electrolyte via Water‐Based Separation: Interactions of Electrode Materials in Aqueous Li <sub>3</sub> InCl <sub>6</sub> Solutions
Direct Recycling of All‐Solid‐State Batteries with a Halide Solid Electrolyte via Water‐Based Separation: Interactions of Electrode Materials in Aqueous Li <sub>3</sub> InCl <sub>6</sub> Solutions Open
Despite extensive research in the field of all‐solid‐state batteries, there has been limited attention to their recycling, which is crucial for achieving long‐term sustainability. Different electrolyte and electrode combinations must be co…
View article: Direct Recycling of All-Solid-State Batteries with a Halide Solid Electrolyte via Water-based Separation: Interactions of Electrode Materials in Aqueous Li3InCl6 Solutions
Direct Recycling of All-Solid-State Batteries with a Halide Solid Electrolyte via Water-based Separation: Interactions of Electrode Materials in Aqueous Li3InCl6 Solutions Open
Despite extensive research in the field of all-solid-state batteries, there has been limited attention to their recycling, which is crucial for achieving long-term sustainability. Different electrolyte and electrode combinations must be co…
View article: Decoding systematic effects and mass transport in H2O2 production via Aux/C ORR electrocatalysis
Decoding systematic effects and mass transport in H2O2 production via Aux/C ORR electrocatalysis Open
Traditionally, evaluating a catalyst's activity has focused on its intrinsic properties. However, the observed catalytic behavior can be significantly influenced by both systematic parameters and mesoscopic mass transport limitations. Alth…
View article: Wafer-scale robust graphene electronics under industrial processing conditions
Wafer-scale robust graphene electronics under industrial processing conditions Open
For commercial grade electronic devices, stable structures are required to ensure a long device life span. When such devices contain nanomaterials like graphene, it is crucial that these materials resist industrial processes and harsh envi…
View article: Printed CsMg–ZnO ETLs achieve over 9 % efficiency in PbS quantum dot solar cells
Printed CsMg–ZnO ETLs achieve over 9 % efficiency in PbS quantum dot solar cells Open
Zinc oxide (ZnO) is a key electron transport layer (ETL) material in next-generation lead sulfide (PbS) colloidal quantum dot solar cells (CQDSCs) due to its high transparency, strong exciton binding energy, and good electron mobility. Her…
View article: Pre-synthetic redox control of structure and properties in copper TTFtt coordination polymers
Pre-synthetic redox control of structure and properties in copper TTFtt coordination polymers Open
Conductive coordination polymers (CPs) with sulfur-based ligands offer strong metal–ligand interactions and redox tunability, making them promising candidates for electronic applications.
View article: Thin Nickel Coatings on Stainless Steel for Enhanced Oxygen Evolution and Reduced Iron Leaching in Alkaline Water Electrolysis
Thin Nickel Coatings on Stainless Steel for Enhanced Oxygen Evolution and Reduced Iron Leaching in Alkaline Water Electrolysis Open
One of the most mature technologies for green hydrogen production is alkaline water electrolysis. However, this process is kinetically limited by the sluggish oxygen evolution reaction (OER). Improving the OER kinetics requires electrocata…
View article: Water dissociation on NiOOH in alkaline water electrolysis improves with increasing alkali metal cation size
Water dissociation on NiOOH in alkaline water electrolysis improves with increasing alkali metal cation size Open
The activity of nickel-based electrocatalysts towards the oxygen evolution reaction (OER) is influenced by the presence of alkali metal cations in the electrolyte. Since the underlying mechanism is not fully resolved yet, we conducted a st…
View article: On the Description of Electrode Materials in Lithium Ion Batteries Based on the Quantification of Work Functions
On the Description of Electrode Materials in Lithium Ion Batteries Based on the Quantification of Work Functions Open
During charging of a lithium ion battery, electrons are transferred from the cathode material to the outer circuit and lithium ions are transferred into the electrolyte. Here, the energy required to take electrons and lithium ions out of t…
View article: Evaluating the effect of oxygen vacancies on the OER activity of LaNiO3
Evaluating the effect of oxygen vacancies on the OER activity of LaNiO3 Open
In this work, we have investigated the effect of oxygen vacancies on the surface composition, electronic structure and OER performance of LaNiO3. The results show that the OER performance of LaNiO3 can be improved both by lowering the oxyg…
View article: Kinetic analysis of the self-discharge of the NiOOH OER active phase in KOH electrolyte: insights from in-situ Raman and UV–Vis reflectance spectroscopies
Kinetic analysis of the self-discharge of the NiOOH OER active phase in KOH electrolyte: insights from in-situ Raman and UV–Vis reflectance spectroscopies Open
NiOOH has been established as the active phase of NiO-based electrocatalysts in the alkaline Oxygen Evolution Reaction (OER). Here, we investigate the self-discharge behavior of NiOOH electrodes under open circuit potential (OCP) condition…
View article: Evaluating the electronic structure and stability of epitaxially grown Sr-doped LaFeO<sub>3</sub> perovskite alkaline O<sub>2</sub> evolution model electrocatalysts
Evaluating the electronic structure and stability of epitaxially grown Sr-doped LaFeO<sub>3</sub> perovskite alkaline O<sub>2</sub> evolution model electrocatalysts Open
O 2 evolution activity of La 1− x Sr x FeO 3 depends on the presence of hole states below the conduction-band-minimum, whose stability is compromised by Sr-leaching.