The CRC/TRR 247 aims at bringing heterogeneous oxidation catalysis in the liquid phase to a level of fundamental understanding that is comparable to metal catalysis in the gas phase, i.e. to unravel the nature of the catalytically active sites and the reaction mechanisms. The research programme is built on three working hypotheses:
(1) The structural prerequisites relevant for efficient oxidation catalysts (active site precursor motifs) can be identified by experimental correlations of structural features beyond the ideal crystal structure with catalytic activity.
(2) Theory together with thorough in situ and operando analysis of these features will enable to clarify the nature and evolution of the working active sites.
(3) A systematic comparison of the same catalyst in a selection of different oxidation reactions of hierarchical complexity and using thermal, electro-, and photocatalysis will deliver trends, from which the generic catalytic functions and – in close collaboration between theory and experiment – the relevant elementary steps and the full reaction mechanism can be deduced.
The central collaborative element of the CRC/TRR 247 will be a Comparative Study that is designed to verify these hypotheses. The materials basis is comprised of mixed cobalt-iron oxides of the spinel and perovskite type, which are active and suitable prototype materials for the elaboration of composition- and structure-activity correlations. The reactions under study are selective oxidations of alcohols, saturated hydrocarbons, olefins and the redox chemistry of dioxygen.
The first funding period will be devoted to the establishment of experimental structure–activity correlations and theoretical modelling of the active site candidates. In the second funding period, we will converge theory and experiment and address the reaction mechanisms. Additionally, we will start to generalize the results to other oxide catalysts. In the third funding period, the generated knowledge will be employed for the rational design of superior new metal oxide catalysts for innovative liquid-phase catalytic processes.