Publications by authors named "Kahyun Ham"

Nickel-iron (oxy)hydroxide (NiFeOH) stands as a cutting-edge nonprecious electrocatalyst for the oxygen evolution reaction (OER). However, the intrinsic thermodynamic instability of nickel and iron as anode materials in pure water-fed electrolyzers poses a significant durability challenge. In this study, an anion exchange ionomer coating was applied to NiFeOH to modify the local pH between a membrane and an electrode.

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Compared to hydrogen oxidation reaction, oxygen reduction reaction (ORR) is a sluggish reaction in the proton exchange membrane fuel cell. Many studies have focused on the development of complex synthesis methods for new catalysts. In this study, we introduce a simple catalyst layer preparation method using an additive based on physical mixing for facile ORR in acid media.

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NiFe-based oxides are one of the best-known active oxygen evolution electrocatalysts. Unfortunately, they rapidly lost performance in Fe-purified KOH during the reaction. Herein, tetraphenylporphyrin (TPP) was loaded on a catalyst/electrolyte interface to alleviate the destabilization of NiFe (oxy)hydroxide.

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Invited for this month's cover is the group of Jaeyoung Lee at the Gwangju Institute of Science and Technology (GIST). The cover image shows how the lone-pair electrons on N atoms could play a role in both uniform nucleation of Pt nanoparticles and facile oxygen reduction reaction (ORR). Strong Pt-N interaction based on π-backdonation improves not only the activity of the ORR but also the durability in the polymer exchange membrane fuel cells.

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An N-doped carbon with various N concentrations was prepared by using a scalable ball-milling method. The importance of the lone pair of electrons on the N species for the stability of Pt nanoparticles and their activity toward the oxygen reduction reaction was investigated. X-ray spectroscopic analysis was used to investigate the interaction between Pt and the pyridinic N.

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There is a growing need for widespread deployment of hydrogen and fuel cell technology for the realization of a sustainable energy landscape. However, due to the high price of platinum (Pt) catalysts, it is necessary to develop highly active and stable non-Pt oxygen reduction reaction (ORR) catalysts. Here, we describe a rational design of nonnoble metal-embedding and nitrogen-containing carbon nanofiber (M-CNF) catalysts.

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