双金属等离子体催化剂中的热载流子产生理论

Atomistic simulations of the structures of Pd-Pt bimetallic nanoparticles and nanowires

Bimetallic nanoalloys such as nanoparticles and nanowires are attracting significant attention due to their vast potential applications such as in catalysis and nanoelectronics. Notably, Pd-Pt nanoparticles/nanowires are being widely recognized as catalysts and hydrogen sensors. Compared to unary systems, alloys present more structural complexity with various compositional configurations. Therefore, it is important to understand energetically preferred atomic structures of bimetallic nanoalloys. In this study, we performed a series of simulated annealing Monte Carlo simulations to predict the …

铁和钴双金属簇的结构用于优化化学气相沉积生长单壁碳纳米管

Structures of iron and cobalt bimetallic clusters for optimized chemical vapor deposition growth of single-walled carbon nanotubes

研究通过铁钴双金属簇优化化学气相沉积生长单壁碳纳米管，发现Fe0.75Co0.25合金在高温下促进大直径纳米管生长。

Gas-induced segregation in Pt-Rh alloy nanoparticles observed by in-situ Bragg coherent diffraction imaging

Bimetallic catalysts can undergo segregation or redistribution of the metals driven by oxidizing and reducing environments. Bragg coherent diffraction imaging (BCDI) was used to relate displacement fields to compositional distributions in crystalline Pt-Rh alloy nanoparticles. 3D images of internal composition showed that the radial distribution of compositions reverses partially between the surface shell and the core when gas flow changes between O2 and H2. Our observation suggests that the elemental segregation of nanoparticle catalysts should be highly active during heterogeneous catalysis …

Plasmonic enhancement of molecular hydrogen dissociation on metallic magnesium nanoclusters

Light-driven plasmonic enhancement of chemical reactions on metal catalysts is a promising strategy to achieve highly selective and efficient chemical transformations. The study of plasmonic catalyst materials has traditionally focused on late transition metals such as Au, Ag, and Cu. In recent years, there has been increasing interest in the plasmonic properties of a set of earth-abundant elements such as Mg, which exhibit interesting hydrogenation chemistry with potential applications in hydrogen storage. This work explores the optical, electronic, and catalytic properties of a set of metall…

Kinetic Expression for Optimal Catalyst Electronic Configuration: The Case of Ammonia Decomposition

A new steady-state kinetic model of ammonia decomposition is presented and analyzed regarding the electronic properties of metal catalysts. The model is based on the classical Temkin-Ertl mechanism and modified in accordance with Wolkenstein electronic theory by implementing participation of free electrons of the catalyst to change the chemical nature of adsorbed species. Wolkenstein original theory only applied to semiconductors but by including the d-band model, the electronic theory can be extended to metals. For both simplified and full reaction mechanisms, including electronic steps, we p…

Single-atom dopants in plasmonic nanocatalysts

Bimetallic nanostructures combining plasmonic and catalytic metals are promising for tailoring and enhancing plasmonic hot-carrier generation utilized in plasmonic catalysis. In this work, we study the plasmonic hot-carrier generation in noble metal nanoparticles (Ag, Au, Cu) with single-atom dopants (Ag, Au, Cu, Pd, Pt) with first-principles time-dependent density-functional theory calculations. Our results show that the local hot-carrier generation at the dopant atom is significantly altered by the dopant element while the plasmonic response of the nanoparticle as a whole is not significantl…

用于催化反应的Pd/Cu单原子合金：从单晶到纳米结构模型系统以实现高选择性丁醇脱氢

Pd/Cu single atom alloys for catalysis: from single crystalline to nanostructured model systems for highly selective butanol dehydrogenation

本研究开发了一种Pd原子级分散于Cu纳米颗粒的Pd/Cu单原子合金催化剂，结合多种表面敏感技术与DFT计算进行表征，发现其在丁醇脱氢制丁醛反应中实现100%选择性，优于单晶模型体系，为相关催化材料的合理设计奠定了基础。

Design-controlled Synthesis of IrO$_2$ sub-monolayers on Au Nanodendrites: Marrying Plasmonic and Electrocatalytic Properties

We develop herein plasmonic-catalytic Au-IrO$_2$ nanostructures with a morphology optimized for efficient light harvesting and catalytic surface area; the nanoparticles have a dendritic morphology, with closely spaced Au branches all partially covered by an ultrathin (1 nm) IrO$_2$ shell. This nanoparticle architecture optimizes optical features due to the interactions of closely spaced plasmonic branches forming electromagnetic hot spots, and the ultra-thin IrO$_2$ layer maximizes efficient use of this expensive catalyst. This concept was evaluated towards the enhancement of the electrocataly…

Multidimensional thermally-induced transformation of nest-structured complex Au-Fe nanoalloys towards equilibrium

Bimetallic nanoparticles are often superior candidates for a wide range of technological and biomedical applications, thanks to their enhanced catalytic, optical, and magnetic properties, which are often better than their monometallic counterparts. Most of their properties strongly depend on their chemical composition, crystallographic structure, and phase distribution. However, little is known of how their crystal structure, on the nanoscale, transforms over time at elevated temperatures, even though this knowledge is highly relevant in case nanoparticles are used in, e.g., high-temperature c…

Colloidal Synthesis of Crystalline Aluminum Nanoparticles for UV Plasmonics

Numerous applications of nanotechnologies rely on the wide availability of high-quality crystalline nanoparticles (NPs). Although the chemical synthesis of noble metal nanoparticles (gold and silver) is well mastered, pushing the optical response of metallic nanoparticles towards the ultraviolet requires other materials, such as aluminum. Although a few demonstrations of chemical synthesis of Al nanoparticles have been reported so far, an elaboration path allowing for a wide range of NP size that is compatible with mass production has yet to be demonstrated. In this article, we report on the p…

Particle Shape Control via Etching of Core-Shell Nanocrystals

The application of nanocrystals as heterogeneous catalysts and plasmonic nanoparticles requires fine control of their shape and chemical composition. A promising idea to achieve synergistic effects is to combine two distinct chemical and/or physical functionalities in bi-metallic core-shell nanocrystals. Although techniques for the synthesis of single-component nanocrystals with spherical or anisotropic shape are well established, new methods are sought to tailor multicomponent nanocrystals. Here, we probe etching in a controlled redox environment as a synthesis technique for multi-component n…