Abstract

The development of new and the improvement of existing chemical processes are major priorities in the realm of sustainability. Most of these processes are inconceivable without the use of catalysts. In particular, heterogeneous catalysis is involved in 80-90% of known industrial catalytic processes. The development of new catalysts can lead to the emergence of more efficient and sustainable processes. However, the application of the classical iterative approach is becoming increasingly complicated due to the rapid increase in the number of known catalytic systems.

The implementation of modern techniques for the characterization of materials can significantly enhance our understanding of their formation, interactions, stability, and evolution, thereby increasing the probability of improvements or even the synthesis of entirely new libraries of materials. This is particularly true for heterogeneous catalysts; comprehensive characterization of the catalytic systems throughout the investigation can improve our understanding and reproducibility of processes related to synthesis, interactions with reactive gases, and deactivation.

During this thesis work, we focused on X-ray Photoelectron Spectroscopy (XPS) as the primary technique for investigating heterogeneous catalysts in various reactions. XPS provides invaluable information about the chemical composition and electronic states of the catalyst surface—the interface where the catalytic process occurs. Furthermore, we explored the full potential of the technique by implementing a Near Ambient Pressure X-ray Photoelectron Spectrometer (NAP-XPS), specifically the EnviroESCA model from SPECS GmbH, for the investigation of catalysts during reduction and the Dry Reforming of Methane (DRM) reaction.

Challenges related to sample charging and instrument limitations arose due to the implementation of a new NAP-XPS setup during the investigation of the deactivation of NiMn/ZrO2 catalysts in DRM process, which led to modifications of the equipment and the development of a procedure for further studies.

Finally, the protocol developed for in situ XPS investigation of heterogeneous catalysts was successfully implemented during the reduction studies of PdZn/ZrO2, a catalyst designed for CO2 reduction to methanol, and BaCoCe, employed for the decomposition of ammonia.