Search

Exsolution is an effective method for synthesizing robust nanostructured metal‐based functional materials. However, no studies have investigated the exsolution of metal nanoparticles into metal nitride substrates. In this study, a versatile nitridation‐driven exsolution method is developed for embedding catalytically active metal nanoparticles in conductive metal nitride substrates via the ammonolysis of multimetallic oxides. Using this approach, Ti1−xRuxO2 nanowires are phase‐transformed into holey TiN nanotubes embedded with exsolved Ru nanoparticles. These Ru‐exsolved holey TiN nanotubes exhibit outstanding electrocatalytic activity for the hydrogen evolution reaction with excellent durability, which is significantly higher than that of Ru‐deposited TiN nanotubes. The enhanced stability of the Ru‐exsolved TiN nanotubes can be attributed to the Ru nanoparticles embedded in the robust metal nitride matrix and the formation of interfacial Ti3+─N─Ru4+ bonds. Density functional theory calculations reveal that the exsolved Ru nanoparticles have a lower d‐band center position and optimized hydrogen affinity than deposited Ru nanoparticles, indicating the superior electrocatalyst performance of the former. In situ Raman spectroscopic analysis reveals that the electron transfer from TiN to Ru nanoparticles is enhanced during the electrocatalytic process. The proposed approach opens a new avenue for stabilizing diverse metal nanostructures in many conductive matrices like metal phosphides and chalcogenides. [ABSTRACT FROM AUTHOR]

The hybridization of conductive nanospecies has garnered significant research interest because of its high efficacy in improving the diverse functionalities of nanostructured materials. In this study, a novel synthetic strategy is developed to optimize the defect structure, structural ordering, and energy‐related functionality of nanostructured‐materials by employing a multilayer multicomponent two‐dimenstional (2D) graphene/metal oxide/graphene nanosheet (NS) as a versatile hybridization matrix. The hybridization of the robust trilayer, polydiallyldiammonium (PDDA)‐anchored reduced‐graphene oxide (prGO)/metal oxide/prGO NS effectively enhance the structural ordering and porosity of the hybridized MoS2/MnO2 NS through suppression of defect formation and tight stacking. In comparison with monolayer rGO/RuO2 NS‐based homologs, the 2D superlattice trilayer prGO/RuO2/prGO NS hybrids deliver better functionalities as a hydrogen evolution electrocatalyst and as a supercapacitor electrode, demonstrating the merits of hybridization with multilayer NSs. The advantages of using multilayer multicomponent conductive NSs as hybridization matrices arise from the enhancement of charge and mass transport through the layer flattening or defect suppression of the hybridized NSs and the increase in porosity, as evidenced by density functional theory calculations. Finally, the universal utility of multilayer NSs is confirmed by investigating the strong effect of the stacking order on the electrocatalytic functionality of MoS2/rGO/RuO2 films fabricated through layer‐by‐layer deposition. [ABSTRACT FROM AUTHOR]

A defect engineering of inorganic solids garners great deal of research activities because of its high efficacy to optimize diverse energy‐related functionalities of nanostructured materials. In this study, a novel in situ defect engineering route to maximize electrocatalytic redox activity of inorganic nanosheet is developed by using holey nanostructured substrate with strong interfacial electronic coupling. Density functional theory calculations and in situ spectroscopic analyses confirm that efficient interfacial charge transfer takes place between holey TiN and Ni−Fe‐layered double hydroxide (LDH), leading to the feedback formation of nitrogen vacancies and a maximization of cation redox activity. The holey TiN−LDH nanohybrid is found to exhibit a superior functionality as an oxygen electrocatalyst and electrode for Li−O2 batteries compared to its non‐holey homologues. The great impact of hybridization‐driven vacancy introduction on the electrochemical performance originates from an efficient electrochemical activation of both Fe and Ni ions during electrocatalytic process, a reinforcement of interfacial electronic coupling, an increase in electrochemical active sites, and an improvement in electrocatalysis/charge‐transfer kinetics. [ABSTRACT FROM AUTHOR]