Complex Model Electrocatalysts for the Selective Transformation of Renewable Fuels

• Applicant: Dr. Olaf Brummel
• Subject Area: Physical Chemistry of Solids and Surfaces, Material Characterisation
• Term: from 2019 to 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 431733372

This project aims at the development of complex electrocatalysts for the selective oxidation of ethanol in alkaline electrochemical environments. The applicants envision a model approach to build complex, yet atomically defined model systems, by combining the specific functionalities required for efficient ethanol conversion. Particularly, three functionalities have to be coupled at the nanoscale: i) strong anchoring of ethanol, ii) C-C bond cleavage, and iii) oxidation of ethanol derivatives. The contribution from each of the specific functionalities and their synergistic interaction will be investigated on materials with different degrees of structural and chemical complexity. Our strategy comprises three types of model systems: (i) well-ordered oxide films (reducible oxides), (ii) oxide nanoparticles supported on well-ordered metal substrates (inverse catalysts), and (iii) noble metal nanoparticles supported on well-ordered oxide films (model catalysts). At the highest level of complexity, model systems will be built which comprise bimetallic nanoalloys on reducible oxides. For each type of model, we will maintain full atomic-level control. This will be achieved by assembling the models in ultrahigh vacuum followed by transfer into the electrochemical environment under well-defined conditions. The stability of the model systems will be investigated in alkaline environment as a function of pH and electrode potential. The structure and chemical state of the model systems will be investigated by in-situ and ex-situ methods, in order to identify the conditions under which the model interfaces are stable during reaction in the liquid electrochemical environment. Using these models, we will explore individual functionalities and, subsequently, couple these at the nanoscale, both in UHV and under electrochemical conditions. A unique combination of in-situ methods will be employed to monitor the structure, chemical composition, reactive sites, and product spectrum during ethanol oxidation. The activity and selectivity of the model catalysts will be tuned via parameters such as oxide stoichiometry, oxide structure, particle size, particle shape, nanoalloy stoichiometry, ligand effects, and electronic metal-support interaction. Our proposed model approach will be an important step towards a knowledge-based strategy for the development of complex, multifunctional electrocatalysts. It will be possible to apply similar research strategies to the electrocatalytic conversion of other complex fuels and chemicals from renewable sources, with the aim to increase the efficiency, selectivity, and stability of the corresponding electrocatalytic conversion processes.

• DFG Programme: Research Grants
• International Connection: Czech Republic
• Partner Organisation: Czech Science Foundation
• Cooperation Partner: Dr. Josef Myslivecek
• Co-Investigators: Professor Dr. Jörg Libuda; Dr. Yaroslava Lykhach