Periodic Reporting for period 4 - Cu4Energy (Biomimetic Copper Complexes for Energy Conversion Reactions)
Período documentado: 2019-11-01 hasta 2020-04-30
Many of the molecular catalysts that were explored during the initial stages of the project resulted therefore in formation of deposits on the electrode, even despite some of these were claimed to be molecular catalysts in literature reports previously.
We have unraveled the mechanism of oxygen reduction at various stable, mononuclear and homogeneous copper sites. In these reactions hydrogen peroxide is an obligatory intermediate. On one hand this opens up the possibility to produce hydrogen peroxide electrochemically in a sustainable process. On the other hand this limits potential efforts to push the onset of oxygen reduction above that of the equilibrium potential of hydrogen peroxide oxidation. Minimal yields of peroxide were obtained in case of trinuclear copper sites.
Copper based water oxidation catalysts more easily allow for adjustment of its onset potential. Similar to ruthenium complexes electron donating and/or electron withdrawing ligands at the ligand periphery have a massive effect on the electronics of the catalyst.
From the oxygen evolution part of the overall project we have been able to draw clear relationships between the catalyst structure, electronic effects at the catalytic site, and the reaction conditions. This allows us to pinpoint clear design principles for further catalysts development.