Correlating activities and defects in (photo)electrocatalysts using in-situ multi-modal microscopic imaging.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 38724495.
- Also identified by DOI 10.1038/s41467-024-47870-9 and PMC identifier 11082147.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Photo(electro)catalysts use sunlight to drive chemical reactions such as water splitting. A major factor limiting photocatalyst development is physicochemical heterogeneity which leads to spatially dependent reactivity. To link structure and function in such systems, simultaneous probing of the electrochemical environment at microscopic length scales and a broad range of timescales (ns to s) is required. Here, we address this challenge by developing and applying in-situ (optical) microscopies to map and correlate local electrochemical activity, with hole lifetimes, oxygen vacancy concentrations and photoelectrode crystal structure. Using this multi-modal approach, we study prototypical hematite (α-Fe<sub>2</sub>O<sub>3</sub>) photoelectrodes. We demonstrate that regions of α-Fe<sub>2</sub>O<sub>3</sub>, adjacent to microstructural cracks have a better photoelectrochemical response and reduced back electron recombination due to an optimal oxygen vacancy concentration, with the film thickness and extended light exposure also influencing local activity. Our work highlights the importance of microscopic mapping to understand activity, in even seemingly homogeneous photoelectrodes.