Chapter 5
Covalent Assemblies of Metal
Nanoparticles—Strategies for Synthesis
and Catalytic Applications
Yuanyuan Min, M. Rosa Axet, and Philippe Serp
Abstract Metal nanoparticles’ (NP) covalent assemblies exhibit interesting structural, electronic, and photonic features of interest for applications in catalysis. In these
structures, the ligands play a fundamental role on constructing the NP network and
defining their chemical environment. Two types of strategies to produce NP assemblies are discussed in this chapter: (i) the direct cross-linking method, which is simple
and well-controlled, and involves a chemical reaction between the metal nanoparticle
surface and the ligand; and (ii) the indirect cross-linking method in which the chemical reaction necessary for network building does not directly involve the surface of
the metallic nanoparticle. Additionally, the formation of reversible covalent networks
is also discussed, which allows switching between a covalent network of NP and
isolated NP by applying diverse stimuli. Generally, there is a lack of attention paid
on the catalytic application of metal NP covalent assemblies, and this despite of the
interesting properties of such assemblies for catalysis, for instance: (i) a confined
environment, (ii) the possibility to finely tune the metal/ligand interaction, and (iii)
the potential robustness of the structure. Various reactions catalyzed by NP networks
have been investigated such as reduction, oxidation, or water-splitting, most of them
focusing on Au NP, and also few other metals (Ag, Pd, Pt, Ru). As illustrated in some
cases, the organized networks show better catalytic performances than dispersed or
aggregated NP due to stability or confinement effect.
Keywords Metallic nanoparticles · Covalent assemblies · Ditopic ligand · Gold ·
Catalysis
5.1 Introduction
Metal nanoparticles (NP) have attracted the interest of the catalysis community,
as it has been shown that their inherent properties, such as size, shape, crystallographic structure, in addition to surface modifiers (ligands and/or supports) have a
Y. Min · M. R. Axet · P. Serp (B)
LCC-CNRS, Université de Toulouse, INPT, UPS, 205 Route de Narbonne, 31077 Toulouse
CEDEX 4, France
e-mail: philippe.serp@ensiacet.fr
© Springer Nature Switzerland AG 2020
P. W. N. M. van Leeuwen and C. Claver (eds.), Recent Advances in Nanoparticle Catalysis,
Molecular Catalysis 1, https://doi.org/10.1007/978-3-030-45823-2_5
129
Covalent Assemblies of Metal
Nanoparticles—Strategies for Synthesis
and Catalytic Applications
Yuanyuan Min, M. Rosa Axet, and Philippe Serp
Abstract Metal nanoparticles’ (NP) covalent assemblies exhibit interesting structural, electronic, and photonic features of interest for applications in catalysis. In these
structures, the ligands play a fundamental role on constructing the NP network and
defining their chemical environment. Two types of strategies to produce NP assemblies are discussed in this chapter: (i) the direct cross-linking method, which is simple
and well-controlled, and involves a chemical reaction between the metal nanoparticle
surface and the ligand; and (ii) the indirect cross-linking method in which the chemical reaction necessary for network building does not directly involve the surface of
the metallic nanoparticle. Additionally, the formation of reversible covalent networks
is also discussed, which allows switching between a covalent network of NP and
isolated NP by applying diverse stimuli. Generally, there is a lack of attention paid
on the catalytic application of metal NP covalent assemblies, and this despite of the
interesting properties of such assemblies for catalysis, for instance: (i) a confined
environment, (ii) the possibility to finely tune the metal/ligand interaction, and (iii)
the potential robustness of the structure. Various reactions catalyzed by NP networks
have been investigated such as reduction, oxidation, or water-splitting, most of them
focusing on Au NP, and also few other metals (Ag, Pd, Pt, Ru). As illustrated in some
cases, the organized networks show better catalytic performances than dispersed or
aggregated NP due to stability or confinement effect.
Keywords Metallic nanoparticles · Covalent assemblies · Ditopic ligand · Gold ·
Catalysis
5.1 Introduction
Metal nanoparticles (NP) have attracted the interest of the catalysis community,
as it has been shown that their inherent properties, such as size, shape, crystallographic structure, in addition to surface modifiers (ligands and/or supports) have a
Y. Min · M. R. Axet · P. Serp (B)
LCC-CNRS, Université de Toulouse, INPT, UPS, 205 Route de Narbonne, 31077 Toulouse
CEDEX 4, France
e-mail: philippe.serp@ensiacet.fr
© Springer Nature Switzerland AG 2020
P. W. N. M. van Leeuwen and C. Claver (eds.), Recent Advances in Nanoparticle Catalysis,
Molecular Catalysis 1, https://doi.org/10.1007/978-3-030-45823-2_5
129