High-index faceted noble metal nanostructures drive renewable energy electrocatalysis

Noble metallic nanocrystals are used in a wide variety of applications,such as catalysis,batteries,and bio-and chemical sensors.Most of the previous studies focus on the preparation of thermodynamically stable nanocrystals enclosed by low-index facets and discuss their corresponding catalytic properties.Recently,researchers have found that the nanocrystals with high-index facets(HIFs)are of more interest for electrocatalysis.Herein,we review recent key progress in the synthesis of noble metallic nanoparticles enclosed with HIFs and their facetdependent electrocatalytic behaviors.First,we introduce the concept of HIFs,and establish the correlation between their surface structure and catalytic activity.Then,we discuss various synthetic approaches for controlling the shapes and composition of the nanocrystals enclosed by HIFs.Afterwards,we showcase the enhanced electrocatalytic performance realized by HIF-based nanostructures.Finally,we provide guidance on how to improve the electrocatalysis by engineering HIFs on noble metallic nanocrystals.

Study on the Agricultural Financial Development of South Korea

From the perspective of economic history,this paper explored the evolution process of agricultural financial support launched by the South Korean government. Firstly,it introduced the development process of rural financial policies in South Korea. Secondly,it analyzed the inherent logic of the evolution of rural financial policies in South Korea. Finally,it summarized the experience and implications of rural financial development in South Korea for China.

Interface modulation of twinned Pt Fe nanoplates branched 3D architecture for oxygen reduction catalysis

Highly-branched dendritic Pt-based nanocrystals possess great potential in catalyzing the oxygen reduction reaction(ORR),but encounter performance ceiling due to their poor thermal and electrochemical stability.Here,we present a novel Pt Fe nanodendrites(NDs)branched with two-dimensional(2 D)twinned nanoplates rather than conventional 1 D nanowires,which breaks the ORR performance ceiling of dendritic catalysts by inducing the unique Pt-skin configuration via rationally thermal treatment.By further hybridizing the Pt-skin Pt Fe NDs/C with amino-functionalized ionic liquids(ILs),we achieve an unprecedented mass activity of 3.15 A/mgPtat 0.9 V versus reversible hydrogen electrode(RHE)in the Pt Fe-based ORR electrocatalytic system.They also show excellent electrocatalytic durability for ORR with negligible activity decay and no apparent structural change after 20,000 cycles,in sharp contrast to the nanowires branched Pt Fe NDs counterpart.The remarkable catalytic performance is attributed to a combination of several structural features,including 2 D morphology,twin boundary,partially ordered phase and strong coordination with amino group.This work highlights the significance of stabilizing electrocatalytic structures via morphology tuning,which thus enables further surface and interface modification for performance breakthrough in ORR electrocatalysis.

WARFARE COMMAND STRATAGEM ANALYSIS FOR WINNING BASED ON LANCHESTER ATTRITION MODELS

Lanchester equations and their extensions are widely used to calculate attrition in warfare models. The current paper addresses the warfare command decision-making problem for winning when the total combats capability of the attacking side is not superior to that of the defending side. For this problem, the corresponding warfare command stratagems, which can transform the battlefield situation, are proposed and analyzed quantitatively by considering the influence of the warfare information factor. The application examples in military conflicts show the feasibility and effectiveness of the proposed model and the warfare command stratagems for winning. The research results may provide a theoretical reference for warfare command decision making.

Rh-doped PdAg nanoparticles as efficient methanol tolerance electrocatalytic materials for oxygen reduction

Direct methanol fuel cells(DMFCs)have received extensive attention on their high efficiency,high reliability,and no carbon emission.Unfortunately,the poor methanol tolerance and sluggish oxygen reduction reaction(ORR)at cathode have seriously hindered their further development.Herein we report the synthesis of a new class of Rh-doped PdAg alloy nanoparticles(NPs)for boosting ORR activity with high methanol tolerance capacity concurrently.The ORR mass activity of typical Rh_4Pd_(40)Ag_(56)NPs is 4.2 times higher than that of commercial Pt catalyst.Moreover,it shows a great methanol tolerance capability by maintaining 92.4%in ORR mass activity in alkaline solution with 0.1 mol L^(à1)methanol,against a big decrease of almost 100%for commercial Pt.Even after 30,000 potential cycles with 1.0 mol L^(à1)methanol,Rh_4Pd_(40)Ag_(56)NPs still retain ORR mass activity of up to 68.3%.DFT calculations reveal that excellent ORR performance with excellent methanol tolerance originates the active d-band-pinning engineering for an efficient site-independent electron-transfer.A generalized d-band mediated fine electron-transfer tuning path has blueprinted for effectively minimizing intrinsic ORR barriers with high current density.The present work highlights the key role of Rh doping in enhancing the ORR activity and methanol tolerance ability of PdAg NPs for future high-performance DMFCs.

MOF derived Co3O4/N-doped carbon nanotubes hybrids as efficient catalysts for sensitive detection of H2O2 and glucose

Developing enzyme-free sensors with high sensitivity and selectivity for H2O2 and glucose is highly desirable for biological science.Especially,it is attractive to exploit noble-metal-free nanomaterials with large surface area and good conductivity as highly active and selective catalysts for molecular detection in enzyme-free sensors.Herein,we successfully fabricate hollow frameworks of Co3O4/N-doped carbon nanotubes(Co3O4/NCNTs)hybrids by the pyrolysis of metal-organic frameworks followed by calcination in the air.The as-prepared novel hollow Co3O4/NCNTs hybrids exhibit excellent electrochemical performance for H2O2 reduction in neutral solutions and glucose oxidation in alkaline solutions.As sensor electrode,the Co3O4/NCNTs show excellent non-enzymatic sensing ability towards H2O2 response with a sensitivity of 87.40μA(mmol/L)^-1 cm^-2,a linear range of 5.00μmol/L-11.00 mmol/L,and a detection limitation of 1μmol/L in H2O2 detection,and a good glucose detection performance with 5μmol/L.These excellent electrochemical performances endow the hollow Co3O4/NCNTs as promising alternative to enzymes in the biological applications.