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Lithium–sulfur (Li–S) batteries are regarded as promising candidates for next‐generation energy storage systems. However, the slow kinetics and shuttle effects of polysulfides hinder their practical applications. Designing high‐efficiency catalysts to enhance the kinetics and suppress shuttling is one major task for the building of durable Li–S batteries. Here, a Co/CoSe junction is reported to catalyzepolysulfide conversion efficiently because the junction has metallic electron mobility and field‐enhanced catalytic activity. The mechanistic investigation reveals that the difference in the work functions of Co and CoSe rearranges the charge distribution in the junction and strengthens the interaction between polysulfides and CoSe, thereby yielding high catalytic activity. In addition, the relative stability of CoSe, as compared to Co, renders the junction durable upon cycling; therefore, demonstrating long‐term catalytic activity. Such a junction makes full use of metal‐like conductivity and field‐enhanced catalysis and provides an alternative approach to enhancing the catalytic conversion of polysulfides. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Recent progress in colloidal synthesis has realized the preparations of uniform nanocrystal (NC) model catalysts with rich and well‐controlled morphologies that were employed to explore structure‐activity relationships of powder catalysts, similar to single‐crystal‐based model catalysts under ultrahigh vacuum conditions but can work at the same conditions as powder catalysts without the "materials gap" and "pressure gap". In this perspective, the CeO2‐based NC model catalysts with various morphologies are included and their relevant progresses are critically reviewed. The detailed descriptions of morphology‐controlled synthesis and characterizations of uniform CeO2 NCs, and morphology‐dependent catalysis of CeO2‐based NC model catalysts containing pure CeO2 NCs, CeO2‐supported oxide catalysts, and CeO2‐supported metal catalysts, provide us a comprehensive cognition in CeO2‐involved catalytic reactions and also open up a new approach for the fundamental studies of complex heterogeneous catalysis. Finally, a concept of oxide‐based NC model catalysts and outlook of oxide NCs acting not only as model catalysts for the fundamental study but also as the support in tailoring structures and optimizing performance of oxide‐involved catalysts are discussed. [ABSTRACT FROM AUTHOR]