Insights into structure of metal nanomaterials in reactive environments

Abstract

Metal nanomaterials are of great importance in the field of heterogeneous catalysis. In general, the catalytic performances of metal nanomaterials are determined by the structures. However, far from being static, dynamic reconstruction of metal nanomaterials constantly occurs in reactive environments, resulting in different catalytic activities. This review summarizes the latest progress of theoretical understanding of the driving forces for the structural changes. In the first part, some typical ex situ and in situ experimental observations of catalysts in reactive environments are briefly introduced, including the changes of shape, size, and alloy composition of metal or bimetallic nanomaterials. Next, we review the state-of-the-art advancement of the theoretical calculations and simulation methods to understand these experimental observations, and categorize them according to the different driving forces, for example, the oxidation and reduction effects, adsorption-induced reconstruction. Moreover, this review provides many examples for the quantitative agreement between theoretical modeling and experimental observations, which indicates the potential applications for the rational design of high-performance metal nanocatalysts in real reactions.

Catalytic NO Reduction by NO Pre‐Adsorbed RhCeO2NO−Clusters

“…The metal‐reactant interactions [4a,5b,c] that commonly exist in heterogeneous catalysis have been highlighted to influence the morphology and reactivity of related catalysts. For instance, the mobile single‐atom active site (AuCO) [15] and the active single‐atom complex (IrCO) [16] caused by CO adsorption have been experimentally observed and theoretically substantiated to account for the extraordinary catalytic reactions under working conditions.…”

Theory of Anisotropic Metal Nanostructures

“…121 I omit the discussion of aggregative particle growth mechanisms and of the shapes of supported metal nanocrystals, as both have been the subjects of recent reviews. 122,123 In this review, I will discuss selected studies in which theory was used to gain insight into the thermodynamics and kinetics of nanocrystal shapes. As such, this review is not a "deep dive" into the theoretical methods themselves, but more what could be learned from these methods.…”

“…The focus of this review, on multiscale atomistic techniques based on quantum mechanics, distinguishes it from prior reviews of the theory of nanocrystal growth and shapes . I omit the discussion of aggregative particle growth mechanisms and of the shapes of supported metal nanocrystals, as both have been the subjects of recent reviews. , …”

Effects of CO and NO atmospheres on the morphology of Ag, Ni, and Ir nanoparticles

“…The high catalytic activity of metal nanoparticles is mainly attributed to the presence of highly active sites on their surface, which usually have a low coordination number [3]. Different size and shape [6][7][8][9][10]. Consequently, metal nanoparticles with special shapes were prepared to enhance their activity in the reaction.…”

“…Consequently, metal nanoparticles with special shapes were prepared to enhance their activity in the reaction. However, the prepared metal nanoparticles may undergo structural changes during the reaction [3,4,9,[11][12][13][14][15][16][17][18], which can lead to modifications in their catalytic properties [19][20][21][22]. For example, Frey et al conducted a study on the dynamic interaction of metal nanoparticles with oxide carriers under redox conditions.…”