There is life after coking for Ir nanocatalyst superlattices

Abstract

Achieving superior performance of nanoparticle systems is one of the biggest challenges in catalysis. Two major phenomena, occurring during the reactions, hinder the development of the full potential of nanoparticle catalysts: sintering and contamination with carbon containing species, sometimes called coking. Here, we demonstrate that Ir nanocrystals, arranged into periodic networks on hexagonal boron nitride (h-BN) supports, can be restored without sintering after contamination by persistent carbon. This restoration yields the complete removal of carbon from the nanocrystals, which keep their crystalline structure, allowing operation without degradation. These findings, together with the possibility of fine tuning the nanocrystals size, confer this nanoparticle system a great potential as a testbed to extract key information about catalysis-mediated oxidation reactions. For the case of the CO oxidation by O2, reaction of interest in environmental science and green energy production, the existence of chemical processes not observed before in other nanoparticle systems is demonstrated.