Project Title:
SFB1615 – Subproject B02: In situ diagnostics and control of electrowetting of carbon nanotube catalysts for application in multiphase reactors

Related Publication:
G. Gizer, H. M. Zeeshan, H. Appala, K. C. Bharatula, B. Wollak, O. Korup, F. Igoa, P. Glaevecke, A. Dippel, M. Schmidt, R. Horn,
"Iso-Potential Operando X-Ray Diffraction (IPO-XRD) – A Novel Approach for Monitoring Catalyst Dynamics in Reactors at Synchrotron and Laboratory Sources",
Hamburg University of Technology (TUHH), 2026.

Abstract of the publication:
Understanding catalyst structure under realistic reaction conditions remains a major challenge in heterogeneous catalysis, particularly in the presence of strong spatial gradients in industrial reactors. Here, we introduce Iso-Potential Operando X-ray Diffraction (IPO-XRD), a novel methodology that decouples reactor operation from diffraction measurements while preserving local reaction conditions. By combining a Compact Profile Reactor with a standard XRD transmission capillary through iso-potential coupling, IPO-XRD enables the direct correlation of gas composition, temperature, and crystalline phase evolution along catalytic beds. The approach is demonstrated for the oxidative dehydrogenation of ethane over a 30 wt% MoO3/γ-Al2O3 catalyst, a system exhibiting pronounced and reversible structural dynamics. IPO-XRD captures the spatial transition from oxidized molybdenum phases (Al2(MoO4)3 and Mo-suboxides) to reduced MoO2, directly linked to the depletion of gas-phase oxygen. Excellent agreement between iso-potential measurements and direct reactor measurements at a synchrotron confirrms the validity of the concept, while additional experiments on a laboratory diffractometer demonstrate its broader applicability. By providing spatially resolved, operando structural information under true reaction conditions, IPO-XRD represents a powerful and versatile tool for investigating catalyst dynamics. The method enables effcient use of synchrotron beamtime and opens new avenues for catalyst characterization across laboratory and industrially relevant environments.

Principal Investigator:
Horn, Raimund
Affiliation:
Email: horn@tuhh.de
ORCID: 0000-0001-8457-3161

Data Creators:
Gizer, Goekhan
Affiliation: Institute for Chemical Reaction Engineering at TUHH Hamburg
Email: goekhan.gizer@tuhh.de
ORCID: 0000-0002-1268-8610

Hafiz Muhammad, Zeeshan
Affiliation: Institute for Chemical Reaction Engineering at TUHH Hamburg
Email: hafiz.zeeshan@tuhh.de
ORCID: 0000-0002-3187-4494

Funding Acknowledgement:
This data set was generated as part of the DFG-funded project CRC 1615: SMART Reactors for Future Process Engineering (DFG Project Number: 503850735).

1. General Information

Data set Title:
XRD and GC data for oxidative dehydrogenation of ethane (IPO-XRD study)


Short Description:
This dataset contains XRD and GC data for the oxidative dehydrogenation of ethane over a 30 wt. percent MoO3/γ-Al2O3 catalyst. The system exhibits pronounced and reversible structural dynamics. 
The IPO-XRD method enables spatially resolved monitoring of phase transitions from oxidized molybdenum species (Al2(MoO4)3 and Mo suboxides) to reduced MoO2, directly linked to the depletion of gas-phase oxygen. 
Iso potential idea can be explained as following: 
-The gas is feeded to CPR using dedicated mass flow controllers. Small amount of reaction mixture at the position of sampling orifice is transferred into a spectroscopic cell containing a tiny amount (few mg) of the same catalyst as inside the reactor, just enough to measure the desired spectroscopic information but as little as possible to minimize conversion in the spectroscopic cell. Once the reaction fluid is separated from the catalyst in the reactor, the chemical composition denoted by a mole fraction vector x is fixed. The pressure drop in the transfer system is kept very small (less than 100 mbar) such that the pressure p in the spectroscopic cell is the same as locally in the reactor. The temperature T of the catalyst in the spectroscopic cell is set to the same value as measured locally in the reactor. In this way, the catalyst in the spectroscopic cell is exposed to the same chemical potential as the catalyst locally in the reactor μ(T, p, x)reactor = μ(T, p, x)spec. cell ⇒ iso potential and should display the same adsorbates, oxidation state and crystalline phases. By scanning the profile reactor from inlet to outlet, the catalyst in the spectroscopic cell goes in good approximation through the same chemical history as the catalyst in the reactor, and spatial profiles of the respective spectroscopic information can be measured.
Data were collected from both synchrotron and laboratory sources to demonstrate the method’s validity and broader applicability. 
The dataset includes raw and processed data as well as figures (.png), and all raw data are additionally provided as .csv for vendor-independent use.

Date of Data Collection:
23.05.2022–19.11.2025

Geographical Coverage:
Institute for Chemical Reaction Engineering at TUHH Hamburg

Keywords:
IPO-XRD, X-ray diffraction, GC data, catalyst dynamics, MoO3/γ-Al2O3, oxidative dehydrogenation, synchrotron, laboratory, multiphase reactors, SMART reactors

2. Methodological Information

Data Collection and Processing:
XRD data were collected using both synchrotron and laboratory diffractometers. GC data were recorded simultaneously to monitor gas-phase composition. Data were processed using Origin 2025b, with raw tables exported to .csv for compatibility.

Experimental Design / Study Context:
The study investigates structural dynamics of a 30 wt. % MoO3/γ-Al2O3 catalyst during oxidative dehydrogenation of ethane. Measurements include temperature, reactor position, and gas-phase oxygen concentration. The IPO-XRD method allows correlating phase changes with reactor conditions.

Data Validation and Quality Assurance:
Data accuracy and consistency were checked by comparison between iso-potential measurements and direct reactor measurements at synchrotron sources, as well as repeated experiments in the laboratory.

3. Data and File Overview

List of Files and Structure:
File / Folder	Description	Format	Size
XRD_data/	Raw and processed XRD measurements	.asc, .opju, .csv	12.2 MB
GC_data/	Raw and processed gas chromatography data	.xlsx, .opju, .csv	459 KB
Figures/	Illustrative figures of catalyst dynamics	.pptx, .png	33.5 MB
README.txt	This file – usage instructions and metadata	.txt	8 KB

File Naming Convention:
Example filename: 20251119_CRC1615_B02_Lab_XRD_position_10mm.asc
- YYYYMMDD: Date of creation
- CRC1615: Research project
- B02: Subproject identifier
- Lab_XRD: Measurement method
- position_10mm: Position of the catalyst in the reactor

Number of Records:
XRD_data: 47 files; GC_data: 6 files

4. Access and Licensing Information

Repository and Persistent Identifier:
Published via TORE, DOI: https://doi.org/10.15480/882.15279

License for Use:
- Raw data files (.asc, .opju, .xlsx, .csv): Public Domain Mark (PDM)
- Figures (.png): CC BY 4.0

Access Restrictions:
Open access

Text for Citation:

For raw data (Public Domain):
G. Gizer, H. M. Zeeshan,
"IPO-XRD Data for Oxidative Dehydrogenation of Ethane over MoO3/γ-Al2O3",
Hamburg University of Technology (TUHH), 2026,
DOI: https://doi.org/10.15480/882.15279

For figures (CC BY 4.0):
G. Gizer, H. M. Zeeshan, et al.,
"Iso-Potential Operando X-Ray Diffraction (IPO-XRD) – Figures Illustrating Catalyst Dynamics",
Hamburg University of Technology (TUHH), 2026,
DOI: https://doi.org/10.15480/882.15279

5. Reproducibility and Software Dependencies

Software Required:
- Origin 2025b (.opju files)
- Microsoft Excel or compatible software (.xlsx files)
- Any text editor or spreadsheet software for .csv files
- Image viewer for .png files

Scripts and Workflow:
Data processing scripts are included in .opju files. Analyses can be reproduced using .csv files with standard spreadsheet or analysis software.

Reproducibility Notes:
Key results from the related publication can be reproduced by comparing XRD phase transitions with gas-phase composition data under the reported experimental conditions.

6. Ethical and Legal Aspects
Data Protection:
No personal or sensitive data included; not applicable.

Consent Statement:
Not applicable

7. Versioning and Updates
Version Number:
v1.0

Date of Release:
2026-04-08

Change Log:
Initial release

8. Contact Information
Corresponding Author:
Name: Raimund Horn
Institution: Hamburg University of Technology (TUHH)
Email: horn@tuhh.de
ORCID: 0000-0001-8457-3161
Project Website: https://www.tuhh.de/sfb1615/