Shuo Sun,Tong Yang,Yong Zheng Luo,Jian Gou,Yuli Huang,Chengding Gu,Zhirui Ma,Xu Lian,Sisheng Duan,Andrew T. S. Wee,Min Lai,Jia Lin Zhang,Yuan Ping Feng,Wei Chen
The degree of buckling of two-dimensional (2D) materials can have a dramatic impact on their corresponding electronic structures. Antimonene (β-phase), a new 2D material with air stability and promising electronic properties, has been engineered to adopt flat or two-heights-buckling geometries by employing different supporting substrates for epitaxial growth. However, studies of the antimonene monolayer with a more buckled configuration are still lacking. Here, we report the synthesis of an antimonene monolayer with a three-heights-buckling configuration overlaid on SbAg2 surface alloy-covered Ag(111) by molecular beam epitaxy, in which the underlying surface alloy provides interfacial interactions to modulate the structure of the antimonene monolayer. The atomic structure of the synthesized antimonene has been precisely identified through a combination of low-temperature scanning tunneling microscopy and density functional theory calculations. The successful fabrication of a buckled antimonene monolayer could provide a promising way to modulate the structures of 2D materials for future electronic and optoelectronic applications.
The application of electrochemical CO2 reduction reaction (CO2RR) to generate value-added products, including carbon monoxide (CO), represents a sustainable strategy for addressing the global carbon balance. Silver (Ag) has gained significant attention as an attractive and cost-effective electrocatalyst for CO2RR-to-CO due to high activity. Here, the porous Ag nanofoam catalysts with Ag(111)-dominant were prepared by in-situ electrolysis-deposition method in the ionic liquid (IL) electrolyte. The Ag nanofoam catalysts exhibited exceptional activity in converting CO2 to CO, with a high Faradaic efficiency (> 95%) in a wide range of -1.9 ~ -2.4 V vs. Ag/Ag+ in the 1-butyl-3-methylimidazolium tetrafluoroborate ([Bmim][BF4]) electrolyte. The maximum CO partial current density of -125.40 mA cm-2 was obtained on this Ag nanofoam catalyst, representing 62% improvement over Ag(110)-dominant Ag electrode (-77.35 mA cm-2) at -2.4 V vs Ag/Ag+ in the [Bmim][BF4] electrolyte. Density functional theory calculations demonstrate that the Ag(111) crystal facet formed by in-situ electrolysis-deposition method prefers to adsorb [Bmim][BF4] which can stabilize the reaction intermediate, thereby weakening the reaction free energy and promoting CO2 electroreduction.
Triangular silver nanoplates exhibit excellent optical and catalytic properties in many fields, such as catalysts, sensors and bio-medicine. In this paper, triangular nanoplates were generated just in the presence of sodium citrate through a light-induced ripening process, which were converted from spherical silver nanoparticles by reducing silver nitrate with sodium borohydride. By using UV–Vis spectroscopy, particle size analyzer, transmission electron microscopy (TEM) and Ag + concentration analysis, the effects of precursors during the preparation of triangular nanoplates were systematically investigated and the optimal experimental conditions were determined. Based on density functional theory (DFT), the adsorption energies of citrate ion, malate ion and tartronate ion on Ag (1 1 1), (1 1 0) and (1 0 0) were calculated. In addition, theoretical calculations coupled with experimental observations showed that citrate ion as capping agent could more preferentially bind to Ag (1 1 1) and thus blocked Ag (1 1 1) while only allowing extensive growth along the lateral direction. This well explains sodium citrate is an efficient agent in preparing triangular silver nanoplates.
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