Insights into CO2 Hydrogenation: Tuning the Selectivity towards Alcohols by Investigating Ni-Fe Bimetallic Catalysts

• Applicant: Dr. Nina Sharmen Genz
• Subject Area: Physical Chemistry of Solids and Surfaces, Material Characterisation ; Analytical Chemistry
• Term: from 2020 to 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 452243354

Rising atmospheric CO2 concentration constitutes one of the most challenging problems of today’s society. In view of the proceeding climate change and increasing awareness of its associated consequences, CO2 conversion into fuels and chemicals became a highly relevant topic. Here, hydrogenation of CO2 over non-noble, abundant, and relatively inexpensive metal catalysts constitutes a major advance. One key to conversion of the greenhouse gas CO2 into value-added products is the design of efficient and selective catalysts.Yet, in catalysis research, seeking more efficient and selective catalysts is an ongoing challenge. Rational catalyst design requires a fundamental understanding of the currently applied catalysts and of the reaction mechanism. Such a fundamental understanding can only be deduced by combining various analysis methods, as each method only provides particular information. Additionally, the analysis methods should be applied in situ, under reaction conditions, and operando, by combining several in situ methods, to understand the catalysts under realistic working conditions.For CO2 conversion to methane, Ni-based catalysts are commonly desired due to their high activity and selectivity. However, for CO2 hydrogenation towards alcohols, including long-chain alcohols, the optimal catalyst material is not yet found. Long-chain alcohols are required for various applications in industry and daily life, like as fuels. One possibility to redirect the selectivity in CO2 hydrogenation towards long-chain alcohols over Ni-based catalysts is to combine Ni with another metal, e.g. Fe, by taking advantage of the activity of Ni and the selectivity of Fe in a combined fashion.The main objective of this project is to tune the selectivity in CO2 hydrogenation towards alcohols by applying Ni-Fe/SiO2 catalysts and to gain a fundamental understanding of structure-function correlations of these catalysts. A multifaceted approach will be applied for gaining insights into these bimetallic catalysts at different levels. By doing so, various analysis methods will synergistically corroborate each other. For achieving this, the project will be built up on four pillars: catalysts synthesis and evaluation, detailed structural characterization, light spectroscopy, and X-ray based spectroscopy. Only the combination of the expected results of all four pillars will allow to elucidate the whole picture of the complex Ni-Fe/SiO2 catalysts. This will comprise the successful catalysts synthesis and the understanding of resulted structures and their evolutions, the reaction mechanism, structure sensitive effects, and finally the parameters for tuning the selectivity towards alcohols. Eventually, this multifaceted approach will enable to deduce a general guideline to design next generation bimetallic catalysts for going one step forward in CO2 hydrogenation towards long-chain alcohols.

• DFG Programme: WBP Fellowship
• International Connection: Netherlands
• Host: Professor Dr. Bert Weckhuysen