Alloys on the nanoscale

Abstract

An overview is provided of nanostructured alloy materials as both isolated particles with nanoscale diameter (nanoalloys) and nanoalloy bulk materials with nanoscale structure. The methods for preparing and characterizing these systems from both experimental and theoretical modeling points of view are presented, and the basic knowledge on their structural, catalytic, mechanical, optical, and magnetic properties is reviewed. It is shown that, due to the increased freedom associated with composition and chemical ordering, new physical phenomena appear in metal multicomponent nanosystems, as well as novel or profoundly modified properties: For example, new structural motifs can arise depending on the structural and energetic characteristics of the metal components, and metal component the size of the system. Hence, the catalytic activity, mechanical strength, plasmonic and nonlinear optical, as well as magnetic responses exhibit features in multicomponent nanostructured systems which are different and can in principle be finely tuned nanostructured system with respect to their pure counterparts. The challenges associated with full exploitation of these possibilities are outlined. The chapter starts by defining some concepts and principles specific to the field of nanoalloys which are then used in the next sections (Sect. 11.1). A brief overview of the methods for preparing (Sect. 11.2) and characterizing (Sect. 11.3) nanostructured alloys then follows. The core of the chapter (Sect. 11.4) presents a discussion of the properties of these nanostructured alloy materials, distinguished into: structural, catalytic, optical, and magnetic. Section 11.5 is devoted to nanostructured bulk alloys. A brief section on applications (Sect. 11.6) and an outlook (Sect. 11.7) conclude the chapter.