Ultrathin ceramic coatings are of high interest as protective coatings from aviation to biomedical applications. Here, a generic approach of making scalable ultrathin transition metal-carbide/boride/nitride using immiscibility of two metals is demonstrated. Ultrathin tantalum carbide, nitride, and boride are grown using chemical vapor deposition by heating a tantalum-copper bilayer with corresponding precursor (C H , B powder, and NH ). The ultrathin crystals are found on the copper surface (opposite of the metal-metal junction). A detailed microscopy analysis followed by density functional theory based calculation demonstrates the migration mechanism, where Ta atoms prefer to stay in clusters in the Cu matrix. These ultrathin materials have good interface attachment with Cu, improving the scratch resistance and oxidation resistance of Cu. This metal-metal immiscibility system can be extended to other metals to synthesize metal carbide, boride, and nitride coatings.
The properties and, hence, the application
of materials are dependent
on the way their constituent atoms are arranged. Here, we report a
facile approach to produce body-centered cubic (bcc) and face-centered
cubic (fcc) phases of bimetallic FeCo crystalline nanoparticles embedded
into nitrogen-doped carbon nanotubes (NCNTs) with equal loading and
almost similar particle size for both crystalline phases by a rational
selection of precursors. The two electrocatalysts with similar composition
but different crystalline structures of the encapsulated nanoparticles
have allowed us, for the first time, to account for the effect of
crystal structure on the overall work function of electrocatalysts
and the concomitant correlation with the oxygen reduction reaction
(ORR). This study unveils that the electrocatalysts with lower work
function show lower activation energy to facilitate the ORR. Importantly,
the difference between the ORR activation energy on electrocatalysts
and their respective work functions are found to be identical (∼0.2
eV). A notable decrease in the ORR activity after acid treatment indicates
the significant role of encapsulated FeCo nanoparticles in influencing
the oxygen electrochemistry by modulating the material property of
overall electrocatalysts.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.