Christoph Mahr

Dr. Christoph Mahr

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Research Focus & Metrics

Academic Career Length

12Years (2015-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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3 May 2023 in Chemical Reviews
Verified
Journal Article
Open access
GWGünther Wittstock
Günther Wittstock
MBMarcus Baumer
Marcus Baumer
WDWilke Dononelli
Wilke Dononelli
TKThorsten Klüner
Thorsten Klüner
LLLukas Lührs
Lukas Lührs
AWArne Wittstock
Arne Wittstock
Nanoporous gold (NPG) is characterized by a bicontinuous network of nanometer-sized metallic struts and interconnected pores formed spontaneously by oxidative dissolution of the less noble element from gold alloys. The resulting material exhibits decent catalytic activity for low-temperature, aerobic total as well as partial oxidation reactions, the oxidative coupling of methanol to methyl formate being the prototypical example. This review not only provides a critical discussion of ways to tune the morphology and composition of this material and its implication for catalysis and electrocatalysis, but will also exemplarily review the current mechanistic understanding of the partial oxidation of methanol using information from quantum chemical studies, model studies on single-crystal surfaces, gas phase catalysis, aerobic liquid phase oxidation, and electrocatalysis. In this respect, a particular focus will be on mechanistic aspects not well understood, yet. Apart from the mechanistic aspects of catalysis, best practice examples with respect to material preparation and characterization will be discussed. These can improve the reproducibility of the materials property such as the catalytic activity and selectivity as well as the scope of reactions being identified as the main challenges for a broader application of NPG in target-oriented organic synthesis.

1 November 2015 in Ultramicroscopy
Verified
Journal Article
Closed access
CMChristoph Mahr
Christoph Mahr
KMKnut Müller-Caspary
Knut Müller-Caspary
TGTim Grieb
Tim Grieb
MSMarco Schowalter
Marco Schowalter
TMThorsten Mehrtens
Thorsten Mehrtens
ARAndreas Rosenauer
Andreas Rosenauer

1 August 2017 in Journal of Catalysis
Verified
Journal Article
Closed access
CMChristoph Mahr
Christoph Mahr
PKParomita Kundu
Paromita Kundu
ALAnastasia Lackmann
Anastasia Lackmann
DZDaniele Zanaga
Daniele Zanaga
KTKarsten Thiel
Karsten Thiel
ARAndreas Rosenauer
Andreas Rosenauer

1 September 2017 in Journal of Catalysis
Verified
Journal Article
Closed access
ALAnastasia Lackmann
Anastasia Lackmann
CMChristoph Mahr
Christoph Mahr
MSMarco Schowalter
Marco Schowalter
LFLisa Fitzek
Lisa Fitzek
JWJörg Weissmüller
Jörg Weissmüller
AWArne Wittstock
Arne Wittstock

7 March 2017 in Physical Chemistry Chemical Physics
Verified
Journal Article
Closed access
PDF file
JSJ. Shi
J. Shi
CMChristoph Mahr
Christoph Mahr
MMM. M. Murshed
M. M. Murshed
TGThorsten M. Gesing
Thorsten M. Gesing
ARA. Rosenauer
A. Rosenauer
AWArne Wittstock
Arne Wittstock
Methanol as a green and renewable resource can be used to generate hydrogen by reforming, i.e., its catalytic oxidation with water. In combination with a fuel cell this hydrogen can be converted into electrical energy, a favorable concept, in particular for mobile applications. Its realization requires the development of novel types of structured catalysts, applicable in small scale reactor designs. Here, three different types of such catalysts were investigated for the steam reforming of methanol (SRM). Oxides such as TiO2 and CeO2 and mixtures thereof (Ce1Ti2Ox) were deposited inside a bulk nanoporous gold (npAu) material using wet chemical impregnation procedures. Transmission electron and scanning electron microscopy reveal oxide nanoparticles (1–2 nm in size) abundantly covering the strongly curved surface of the nanoporous gold host (ligaments and pores on the order of 40 nm in size). These catalysts were investigated in a laboratory scaled flow reactor. First conversion of methanol was detected at 200 °C. The measured turn over frequency at 300 °C of the CeOx/npAu catalyst was 0.06 s−1. Parallel investigation by in situ infrared spectroscopy (DRIFTS) reveals that the activation of water and the formation of OHads are the key to the activity/selectivity of the catalysts. While all catalysts generate sufficient OHads to prevent complete dehydrogenation of methanol to CO, only the most active catalysts (e.g., CeOx/npAu) show direct reaction with formic acid and its decomposition to CO2 and H2. The combination of flow reactor studies and in operando DRIFTS, thus, opens the door to further development of this type of catalyst.

1 February 2021 in Ultramicroscopy
Verified
Journal Article
Closed access
CMChristoph Mahr
Christoph Mahr
KMKnut Müller-Caspary
Knut Müller-Caspary
TGTim Grieb
Tim Grieb
FKFlorian F. Krause
Florian F. Krause
MSMarco Schowalter
Marco Schowalter
ARAndreas Rosenauer
Andreas Rosenauer