# Hydrocarbon Formation from Syngas with In-Operando Monitoring of Cobalt- and Manganese-Based (pre)Catalysts Using X-ray Diffraction

## TL;DR

This study explores how different metal oxides act as precatalysts in converting syngas into hydrocarbons, with a focus on cobalt and manganese-based materials.

## Contribution

The paper introduces a novel in-operando X-ray diffraction method to monitor catalyst transformations during syngas conversion.

## Key findings

- LiCoO2 precatalyst produced higher hydrocarbon conversions with low olefin-to-paraffin ratios.
- Cobalt-doped birnessite showed lower conversions but a high olefin-to-paraffin ratio of over 20:1.
- In situ XRD revealed phase changes in precatalysts during syngas reactions.

## Abstract

Two-layered metal oxides (LiCoO2 and cobalt-doped
KnMnO2, n <
1) were explored as precatalysts for nanoconfined cobalt-based Fischer–Tropsch
catalysts for conversion of syngas (CO and H2) to hydrocarbons.
Ex situ, in situ, and PDF XRD analyses are presented. Based on in
situ XRD analysis, LiCoO2 underwent reduction to predominantly
cubic and hexagonal phases of cobalt metal. Reaction with syngas resulted
in the generation of carbon, cobalt carbide, and lithium carbonate,
in addition to the metallic cobalt phases. In the case of cobalt-doped
birnessite, catalyst activation converted the birnessite phase to
manganite and the cobalt to elemental cobalt, along with similar lithium
and carbon phases. Conversion of syngas to C1 through C7 products was observed. The best conversions were observed
for the LiCoO2 precursor catalyst, with generally a low
olefin-to-paraffin ratio. While the conversions for the cobalt-doped
birnessite precatalyst were generally lower, with lower chain lengths
(up to C5), these catalysts gave a strikingly high olefin-to-paraffin
ratio: in the best case, greater than 20:1.