"Self-Limited Formation of Nanoporous Nickel Heterostructure Catalyst for Electrochemical Hydrogen Production"

Abstract: Nickel has risen as a viable and cost-effective substitute to noble metal catalysts in electrochemical hydrogen production, yet developing air-stable and highly efficient nanostructured nickel-based catalysts remains a significant challenge. Here we report a facile method for creating nanoporous Ni/NiO heterostructure catalysts for electrocatalytic hydrogen production. The protocol employs chemical dealloying to establish a three-dimensional bicontinuous nanoporous structure, followed by a controlled oxidation process to in situ generate uniform NiO surface layers atop the metallic nickel matrix in a self-limiting manner. This approach not only yields highly ......

https://onlinelibrary.wiley.com/doi/10.1002/adfm.202402286

"Mechanically Robust Self-Organized Crack-Free Nanocellular Graphene with Outstanding Electrochemical Properties in Sodium Ion Battery"

Abstract: Crack-free nanocellular graphenes are attractive materials with extraordinary mechanical and electrochemical properties, but their homogeneous synthesis on the centimeter scale is challenging. Here, we report a strong nanocellular graphene film achieved by the self-organization of carbon atoms using liquid metal dealloying and employing a defect-free amorphous precursor. This study demonstrates that a Bi melt strongly catalyzes the self-structuring of graphene layers at low processing temperatures. The robust nanoarchitectured ......

https://onlinelibrary.wiley.com/doi/10.1002/adma.202311792
This research was carried out in close collaboration with Prof. Soo-Hyun Joo from Dankook University and Prof. Hidemi Kato from Tohoku University .

"Ultrafine Nanoporous Intermetallic Catalysts by High-Temperature Liquid Metal Dealloying for Electrochemical Hydrogen Production"

Abstract: Intermetallic compounds formed from non-precious transition metals are promising cost-effective and robust catalysts for electrochemical hydrogen production. However, the development of monolithic nanoporous intermetallics, with ample active sites and sufficient electrocatalytic activity, remains a challenge. Here we report the fabrication of nanoporous Co7Mo6 and Fe7Mo6 intermetallic compounds via liquid metal dealloying. Along with the development of three-dimensional bicontinuous open porosity, high-temperature dealloying overcomes ......

https://www.nature.com/articles/s41467-022-32768-1

This research was carried out in close collaboration with Prof. Hidemi Kato from Tohoku University and Prof. Mingwei Chen from Johns Hopkins University.

"Bulk Diffusion Regulated Nanopore Formation during Vapor Phase Dealloying of a Zn-Cu Alloy"

Abstract: Dealloying is a robust method for fabricating 3D bicontinuous porous materials with open porosity and large specific surface areas. The formation of nanopores usually results from two kinetically competing processes at dealloying fronts: desertion of sacrificed elements and self-assembly of lingered elements by diffusion. Since surface and interface diffusivities are usually much higher than bulk, dealloying is typically fulfilled by the fast processes while the slow bulk alloy diffusion in precursor alloys is not commonly involved into the formation of open porosity during a dealloying process. Here we report that open pore formation in a Cu12Zn88 alloy is regulated by the bulk alloy ......

https://www.sciencedirect.com/science/article/abs/pii/S1359645422005912

"3D Continuously Porous Graphene for Energy Applications"

Abstract: Constructing bulk graphene materials with well-reserved 2D properties is essential for device and engineering applications of atomically thick graphene. In this article, the recent progress in the fabrications and applications of sterically continuous porous graphene with designable microstructures, chemistries, and properties for energy storage and conversion are reviewed. Both template-based and template-free methods have been developed to synthesize the 3D continuously porous graphene, which typically has the microstructure reminiscent of pseudo-periodic minimal surfaces. The 3D graphene can well preserve the properties of 2D graphene of being highly conductive, surface abundant, and mechanically robust, together with unique 2D electronic behaviors. Additionally, the bicontinuous porosity and large curvature offer new functionalities, such as rapid mass transport, ample open ......

https://onlinelibrary.wiley.com/doi/abs/10.1002/adma.202108750

"Effect of Local Atomic Structure on Sodium Ion Storage in Hard Amorphous Carbon"

Abstract: The fundamental understanding of sodium storage mechanisms in amorphous carbon is essential to develop high-performance anode materials for sodium-ion batteries. However, the intrinsic relation between the structure of amorphous carbon and Na⁺ storage remains to be debated due to the difficulty in controlling and characterizing the local atomic configurations of amorphous carbon. Here we report quantitative measurements of Na⁺ storage in a low-temperature dealloyed hard carbon with a tunable local structure from completely disordered micropores to gradually increased graphitic order domains. The structure-capacity-potential correlation not only verifies the disputing “adsorption–intercalation” mechanisms, i.e., Na⁺ intercalation into local graphitic domains for the low-voltage plateaus and adsorption in fully disordered carbon for the sloping voltage profiles, but also unveils a new mechanism of Na⁺ adsorption on defective sites of graphitic carbon in the medium-potential sloping region. The quantitative investigations provide essential insights into the reaction mechanisms of Na⁺ with amorphous carbon for designing advanced sodium-ion battery anodes.

https://pubs.acs.org/doi/full/10.1021/acs.nanolett.1c01595