Phase diagrams guide synthesis of highly ordered intermetallic electrocatalysts: separating alloying and ordering stages.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 36496497.
- Also identified by DOI 10.1038/s41467-022-35457-1 and PMC identifier 9741640.
- 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
Supported platinum intermetallic compound catalysts have attracted considerable attention owing to their remarkable activities and durability for the oxygen reduction reaction in proton-exchange membrane fuel cells. However, the synthesis of highly ordered intermetallic compound catalysts remains a challenge owing to the limited understanding of their formation mechanism under high-temperature conditions. In this study, we perform in-situ high-temperature X-ray diffraction studies to investigate the structural evolution in the impregnation synthesis of carbon-supported intermetallic catalysts. We identify the phase-transition-temperature (TPT)-dependent evolution process that involve concurrent (for alloys with high TPT) or separate (for alloys with low TPT) alloying/ordering stages. Accordingly, we realize the synthesis of highly ordered intermetallic catalysts by adopting a separate annealing protocol with a high-temperature alloying stage and a low-temperature ordering stage, which display a high mass activity of 0.96 A mgPt-1 at 0.9 V in H2-O2 fuel cells and a remarkable durability.