Ultrastable bimetallic Fe_(2)Mo for efficient oxygen reduction reaction in pH-universal applications

Iron-based nanostructures represent an emerging class of catalysts with high electroactivity for oxygen reduction reaction(ORR)in energy storage and conversion technologies.However,current practical applications have been limited by insufficient durability in both alkaline and acidic environments.In particular,limited attention has been paid to stabilizing iron-based catalysts by introducing additional metal by the alloying effect.Herein,we report bimetallic Fe_(2)Mo nanoparticles on N-doped carbon(Fe_(2)Mo/NC)as an efficient and ultra-stable ORR electrocatalyst for the first time.The Fe_(2)Mo/NC catalyst shows high selectivity for a four-electron pathway of ORR and remarkable electrocatalytic activity with high kinetics current density and half-wave potential as well as low Tafel slope in both acidic and alkaline medias.It demonstrates excellent long-term durability with no activity loss even after 10,000 potential cycles.Density functional theory(DFT)calculations have confirmed the modulated electronic structure of formed Fe_(2)Mo,which supports the electron-rich structure for the ORR process.Meanwhile,the mutual protection between Fe and Mo sites guarantees efficient electron transfer and long-term stability,especially under the alkaline environment.This work has supplied an effective strategy to solve the dilemma between high electroactivity and long-term durability for the Fe-based electrocatalysts,which opens a new direction of developing novel electrocatalyst systems for future research.

High-fidelity transfer of area-selective atomic layer deposition grown HfO_(2)through DNA origami-assisted nanolithography

DNA origami-assisted nanolithography(DOANL)for fabricating custom-designed nanomaterials through pattern transfer from DNA origami to different substrates materials are presented.However,the pattern's integrity and resolution face considerable challenges due to the uncontrollable growth of the nanomaterials during transformation and the unclear mechanism of DOANL.Herein,we report a DOANL combined with area-selective atomic layer deposition(ALD)strategy for fabricating custom shapes hafnium oxide(HfO2)with the high-fidelity and high-throughput.We find that the HfO_(2)selectively grows on DNA origami substrates in a hydroxyl-rich area instead of a methyl-rich protective layer.Combined with the merit of the area-selective ALD method,theHfO_(2)atom selectively coated on the DNA origami surface,thus,precisely modeling the shapes with high-precision in our study based on the surface groups difference of DNA origami and the naked hexamethyldisilane(HMDS)-treated substrates,which reveal the mechanical of high-fidelity pattern transfer based on DOANL.As a result,DNA origami structures can program the shape ofHfO_(2)nanostructures.The DOANL that is based on the principle of"bottom-up"precision assembly breaks through the shape complexity and high-throughput fabrication limitation of theHfO_(2)nanostructures,including two-and three-dimensional structures,plane and curved structures,monolithic and hollow structures.Based on the"top-down"accurate fabrication principle,the area-selective ALD on methyl-rich protective layer substrates improves the integrity and resolution of the pattern transfer process.Overall,this work provides a general technology for nanofabrication strategy.