Nanostructured Ni and Ni/Fe (photo)electrocatalysts for efficient water oxidation

The replacement of fossil fuels by alternative clean energy sources is among the most urgent global challenges. In natural photosynthesis, plants collect sunlight to store energy in chemical bonds. Mimicking this process, sunlight can be stored as in solar fuels through artificial photosynthesis. Interest is focused on water splitting (2x H2O -> O2 + 2x H2). The bottleneck of the water splitting is the water oxidation half reaction (2x H2O -> O2 + 2x H+ + 2x e-), hence more efficient and affordable photocatalysts have to be developed. In this project, we introduce new a series of Ni-based nanostructured WOCs with different ligands: dodecanoic acid (Dod), trimesic acid (TM) and their combination, which generate three very distinct nanostructures (nanoparticles or/on coordination polymers). Upon functionalization with additional Fe centres, the resulting anodes behave as powerful water oxidation (photo)electrocatalysts at pH 14.

With the aim of unravelling the role of the Fe centres, the active species during catalysis and/or their stability, operando and exsitu XAS experiments are powerful techniques that can provide information regarding the oxidation state of the metal center or possible changes in the coordination sphere among others, before, during and after the catalytic process. Therefore, characterizing the electronic structure of the key intermediates that govern the catalytic process. These studies will not only shed light on the aspects that control the WO catalysis in Ni/Fe -based systems, but also will ultimately help to the design of future non-precious based water oxidation catalysts.