Report
Teaser, summary, work performed and final results
Periodic Reporting for period 1 - SEARCh (SurfacE structure-Activity-Relationship in atomically-defined, ultrathin film perovskite Catalysts)
Teaser
Due to the intermittency of renewable electricity, conversion to chemical fuel is a necessity for the success of the transition to sustainable energy. A simple and attractive candidate for climate-neutral fuel is hydrogen, which can be produced directly through water splitting...
Summary
Due to the intermittency of renewable electricity, conversion to chemical fuel is a necessity for the success of the transition to sustainable energy. A simple and attractive candidate for climate-neutral fuel is hydrogen, which can be produced directly through water splitting (so-called electrolysis). But substantial market penetration by commercial electrolysers (devices that perform water splitting using electricity) has not been achieved because it is not economically attractive yet. The reason for this lies in the need of expensive catalysts, which are necessary for the reaction. Today\'s catalysts are not stable enough, not efficient enough, and often used expensive and rare elements. To develop and exploit earth-abundant highly active catalyst materials, a detailed understanding of the underlying relationships between catalytic activity and atomic-level surface structure is required.
Therefore, we investigate Ni-Fe-based perovskite thin film catalysts that can be create with atomic precision to achieve the following objectives:
- Revalidate or replace activity trends found for less well-defined surfaces
- Derive an atomistic understanding of the catalysis reaction and degradation mechanisms
- Deduce design rules for beyond-state-of-the-art electrocatalyst materials and communicate them to the catalyst research and production communities for exploitation in “real-world†catalyst materials
The results of SEARCh will thus contribute to the goals of development and deployment of low-carbon technologies in line with the EU’s Strategic Energy Technology Plan.
Work performed
1) We so far investigated the effect of surface composition of the electrocatalyst. We find that exposing the transition-metal site in perovskite oxide catalysts leads to enhanced catalytic activity and demonstrated how such termination-control can be achieved in epitaxial growth
2) We showed that air exposure leads to alteration of the catalyst surface and a decrease in catalytic activity. Therefore, we developed an air-free transfer system to study the inherent activity of the electrocatalysts (quasi in situ electrochemical testing)
3) we showed that doping with Fe or Co leads to enhancement of the electocatalytic activity of LaNiO3 electrocatalysts.
Final results
The importance of the surface composition of electrocatalysts for water electrolysis has not been recognized before. We therefore expect a paradigm shift in the derivation of so-called descriptors, i.e. materials properties that directly correlate with the catalytic activity. So far, they were mainly based on the bulk electronic structure of the catalyst. Our work shows that the surface properties may be dissimilar from the bulk properties, but that the surface is decisive for the catalytic activity. So derivation of descriptors based on surface properties will be more appropriate.
This realization will lead to general improvement in the optimization of electrocatalysts to make a transition to a hydrogen-based, sustainable industry and society more attainable.
We expect that by the end of the project, we will contribute to an in-depth understanding of the effect of doping in electrocatalysts.
Website & more info
More info: http://www.epicatalysts.rwth-aachen.de.