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Oliver Kröcher

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Publications associées (73)

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Experimental and modeling-based analysis of reaction pathways on catalysts for natural gas engines under periodic lean/rich oscillations

Oliver Kröcher, Davide Ferri, Moyu Wang

Methane (CH4) has the prospective of becoming one of the major energy carriers for heavy-duty mobility, but its catalytic abatement remains a challenge. CH4 abatement reaction pathways were analyzed using targeted periodic lean/rich oscillations, which res ...

ELSEVIER SCIENCE SA2022

Mechanochemistry-assisted hydrolysis of softwood over stable sulfonated carbon catalysts in a semi-batch process

Oliver Kröcher, Frédéric Vogel, David Ferdinand Scholz

The hydrolysis of lignocellulose is the first step in saccharide based bio-refining. The recovery of homogeneous acid catalysts imposes great challenges to the feasibility of conventional hydrolysis processes. Herein, we report a strategy to overcome these ...

2019

Water Inhibition of Oxymethylene Dimethyl Ether Synthesis over Zeolite H-Beta: A Combined Kinetic and in Situ ATR-IR Study

Oliver Kröcher, Christophe Jean Baranowski, Thibault Xavier Florian Fovanna

The effect of water on the kinetics of oxymethylene dimethyl ether (OME) synthesis from dimethoxymethane (OME1) and trioxane (TRI) has been investigated in a combined kinetic and in situ infrared spectroscopy study. The kinetic study revealed that a water ...

AMER CHEMICAL SOC2020

Beware of beam damage under reaction conditions: X-ray induced photochemical reduction of supported VOx catalysts during in situ XAS experiments

Oliver Kröcher, Davide Ferri, Olga Safonova, Anna Zabilska

In situ X-ray absorption spectroscopy (XAS) is a powerful technique for the investigation of heterogeneous catalysts and electrocatalysts. The obtained XAS spectra are usually interpreted from the point of view of the investigated chemical processes, there ...

ROYAL SOC CHEMISTRY2022

Mechanistic implications of lanthanum-modification on gold-catalyzed formic acid decomposition under SCR-relevant conditions

Oliver Kröcher, Davide Ferri

The use of formate-based ammonia precursors as alternatives to urea in the selective catalytic reduction (SCR) process requires that formic acid released upon their thermolysis in the hot exhaust is rapidly decomposed to carbon dioxide. This work aims at t ...

ELSEVIER SCIENCE BV2019

Reduction of PdO/Al2O3 in Liquid Cyclohexane Followed In Situ by ATR-IR, High-Energy XRD, and XAS

Oliver Kröcher, Davide Ferri, Thibault Xavier Florian Fovanna

Supported Pd-based catalysts used in heterogeneously catalyzed liquid phase processes often undergo an activation step through reduction of the oxide phase or of the oxidic passivation layer prior to reaction. An oxidized Pd/Al2O3 catalyst was reduced by u ...

AMER CHEMICAL SOC2021

Investigation on the Role of Pd, Pt, Rh in Methane Abatement for Heavy Duty Applications

Oliver Kröcher, Davide Ferri, Moyu Wang

Methane abatement remains a challenge in aftertreatment systems of natural gas engines, currently under discussion in combination with synthetic methane. In this study, Pt/Rh and Pd/Rh-based three-way catalysts are investigated under various transient cond ...

MDPI2022

Grafting of Alkali Metals on Fumed Silica for the Catalytic Dehydrogenation of Methanol to Formaldehyde

Oliver Kröcher, Alimohammad Bahmanpour, Christophe Jean Baranowski

Water free, non-oxidative catalytic dehydrogenation of methanol to formaldehyde is an important process for the formation of anhydrous, molecular formaldehyde (FA). Sodium or sodium-containing salts were shown to catalyze the reaction, but their reaction m ...

Wiley-VCH Verlag2021

N2O Activation and NO Adsorption Control the Simultaneous Conversion of N2O and NO Using NH3 over Fe-ZSM-5

Oliver Kröcher, Filippo Buttignol

Fe-exchanged zeolites are heterogeneous catalysts that can potentially ensure simultaneous conversion of nitrous oxide (N2O) and nitric oxide (NO) using ammonia (NH3) as a selective reducing agent through their selective catalytic reduction reaction (N2O-N ...

AMER CHEMICAL SOC2025

Iron-catalysed cooperative redox mechanism for the simultaneous conversion of nitrous oxide and nitric oxide

Oliver Kröcher, Filippo Buttignol

Iron-exchanged zeolites are often deployed industrially to remediate nitric oxide (NO) and nitrous oxide (N2O) emissions. The nature of the active site and the reaction mechanism involved in the simultaneous removal of NO and N2O remain largely unknown, pr ...

NATURE PORTFOLIO2024

Deactivation and Regeneration of Sulfonated Carbon Catalysts in Hydrothermal Reaction Environments

Oliver Kröcher, Frédéric Vogel

The deactivation pathways of sulfonated carbon catalysts prepared from different carbons were studied during the aqueous‐phase hydrolysis of cellobiose under continuous‐flow conditions. The sulfonation of carbon materials with a low degree of graphitizatio ...

2018

Selective Catalytic Reduction of NOx

Oliver Kröcher

2018

Critical Aspects in the Catalytic Emission Control of Exhaust Gases Containing NH3, NOx and N2O

Oliver Kröcher, Davide Ferri

Ammonia (NH3) is a promising fuel for use in marine applications due to its favorable chemical properties. However, emissions of especially nitrous oxide (N2O), with a global warming potential (GWP) of 273, pose a significant barrier to the adoption of NH3 ...

Cardiff University Press2024

Selective Catalytic Reduction of NO with NH3 on Cu-SSZ-13: Deciphering the Low and High-temperature Rate-limiting Steps by Transient XAS Experiments

Oliver Kröcher, Davide Ferri, Rob Jeremiah G. Nuguid, Adrian Marberger, Patrick Simon Steiger

Cu-exchanged small-pore SSZ-13 catalysts have found wide use for the selective catalytic reduction (SCR) of nitrogen oxides from automotive exhaust gases. The transient working environment of the Cu-SSZ-13 catalyst during NH3-SCR requires studying the rate ...

Wiley-VCH Verlag2020

Monomeric Fe Species in Square Planar Geometry Active for Low Temperature NH3-SCR of NO

Oliver Kröcher, Davide Ferri

Monomeric Fe species in zeolites are considered to be the active sites for the low temperature activity toward ammonia-assisted selective catalytic reduction of nitrogen oxides (NH3-SCR) in exhaust gases. Herein, we report on a preparation method to synthe ...

AMER CHEMICAL SOC2022

Techno-Economic Evaluation of Biological and Fluidised-Bed Based Methanation Process Chains for Grid-Ready Biomethane Production

Oliver Kröcher, Tilman J. Schildhauer, Andreas Gantenbein

Three different power-to-methane process chains with grid injection in two scales (1 MWel and 6 MWel) were analysed regarding their investment and operation cost. The process chains were based on biological or catalytic bubbling fluidised bed methanation i ...

FRONTIERS MEDIA SA2022

HCN production from formaldehyde during the selective catalytic reduction of NOx with NH3 over V2O5/WO3-TiO2

Oliver Kröcher, Davide Ferri, Rob Jeremiah G. Nuguid

Raw exhaust gases may contain notable levels of formaldehyde that can negatively impact the efficiency of after -treatment systems. In the selective catalytic reduction (SCR) of NOx over V2O5/WO3-TiO2, formaldehyde was found to react with NH3 to produce HC ...

ELSEVIER2021

Design of Stable Palladium-Based Zeolite Catalysts for Complete Methane Oxidation by Postsynthesis Zeolite Modification

Oliver Kröcher, Davide Ferri

Catalytic methane oxidation is used in exhaust gas aftertreatment to reduce methane emissions from lean burn natural gas vehicles as well as in stationary combustion processes. Pd/zeolite catalysts provide high activity for this reaction, but they deactiva ...

AMER CHEMICAL SOC2019

Reversible Segregation of Ni in LaFe0.8Ni0.2O3 +/-delta During Coke Removal

Oliver Kröcher, Davide Ferri, Patrick Simon Steiger

The deactivation of supported nickel catalysts by coking is an important technological subject for many chemical processes, especially when high concentrations of unsaturated hydrocarbons are present in the feed gas. Here, the reversible segregation of Ni ...

Wiley-VCH Verlag2018

Recent progress in calcium looping integrated with chemical looping combustion (CaL-CLC) using bifunctional CaO/CuO composites for CO2 capture: A state-of-the-art review

Oliver Kröcher, Muhammad Awais Naeem

Calcium looping integrated with chemical looping combustion (CaL-CLC) process is an efficient and cost-effective CO2 capture technology. In this technique, the heat generated by chemical looping combustion of CuO is used insitu to calcine CaCO3, thus avoid ...

ELSEVIER SCI LTD2023