A Comparison Study of the Catalytic Properties of Au-Based Nanocages, Nanoboxes, and Nanoparticles

Abstract

We have evaluated the catalytic properties of Au-based nanostructures (including nanocages, nanoboxes, and solid nanoparticles) using a model reaction based on the reduction of p-nitrophenol by NaBH(4). From the average reaction rate constants at three different temperatures, we determined the activation energy, the entropy of activation, and the pre-exponential factor for each type of Au nanostructure. The kinetic data indicate that the Au-based nanocages are catalytically more active than both the nanoboxes and nanoparticles probably due to their extremely thin but electrically continuous walls, the high content of Au, and the accessibility of both inner and outer surfaces through the pores in the walls. In addition, a compensation effect was observed in this Au-based catalytic system, which can be primarily interpreted by a model based on kinetic regime switching.

Probing the surface oxidation of chemically synthesised gold nanospheres and nanorods

“…1. However, numerous studies have shown that gold is not as inert as its d 10 configuration suggests which accounts for its pronounced catalytic and electrocatalytic activity [6,[17][18][19][20][21][22][23][24]. This has been attributed to active sites on the surface that consists of atoms or clusters of atoms that have low co-ordination number and have the ability to partake in electrocatalytic reactions [21,22,25,26].…”

Bottom-Up Synthesis of Gold Octahedra with Tailorable Hollow Features

“…(1,2) The ability to control the dimensions of the hollow cavities within such noble metal nanoparticles allows for tailorable control of these unique plasmonic, catalytic, and electronic properties. (3)(4)(5)(6)(7)(8)(9) Consequently, hollow nanostructures have been used in numerous applications, functioning as nanoscale reactors for chemical reactions, (6)(7)(8) capsules for material containment, (10) substrates for generating surface-enhanced Raman scattering, (11)(12)(13) and for a variety of biomedical applications. (14)(15)(16)(17) While there are many methods for generating nanostructures with hollow interiors, (1,2) the vast majority of these procedures require a synthetic step where a sacrificial material is removed to generate the hollow features, as is the case for reactions based on galvanic replacements (18) and selective etchings.…”

Engineering of Au/Ag Nanostructures for Enhanced Electrochemical Performance

“…24 In addition, smaller Au NPs can be more prone to particle aggregation, which can directly influence the available electroactive surface area. This is an issue that can be addressed by changing the capping agent of the particles or by the incorporation of a conducting carbon matrix support to help disperse the NPs.…”

“…23 Other studies support the fact that smaller nanoparticles show higher catalytic activities due to their higher surface-tovolume ratios, however, just smaller Au nanoparticles (NPs) might still not be the optimum candidates for the electrochemical monitoring of different types of redox reactions. 24 A rational behind this z E-mail: anna.samia@case.edu argument is that as the Au NPs become smaller in size, the electron transfer process becomes more dependent on good electrical connections between particles, specifically in situations where the reduction and oxidation sites occur on different particles. 24 In addition, smaller Au NPs can be more prone to particle aggregation, which can directly influence the available electroactive surface area.…”

“…24 A rational behind this z E-mail: anna.samia@case.edu argument is that as the Au NPs become smaller in size, the electron transfer process becomes more dependent on good electrical connections between particles, specifically in situations where the reduction and oxidation sites occur on different particles. 24 In addition, smaller Au NPs can be more prone to particle aggregation, which can directly influence the available electroactive surface area. This is an issue that can be addressed by changing the capping agent of the particles or by the incorporation of a conducting carbon matrix support to help disperse the NPs.…”