Nanomaterials Preparation by Thermolysis of Metal Chelates

Advances in the chemistry and technology of nanomaterials whose sizes are less than 100 nm in at least one dimension led to exponential development in many fields of science and industry [1–19].

The study of thermolysis of metal-containing compounds can be carried out in closed or open systems both under isothermal and non-isothermal conditions using external and internal heating sources. Depending on the tasks, different approaches allow controlling the degree of conversion and determining the choice of equipment for the experimental study of thermolysis of compounds. Weight (thermogravimetry, TG) or volumetric (volumetry) methods are the most common. Although the development of experimental facilities for the study of thermolysis kinetics began in the first quarter of the twentieth century, the current state of TA can be characterized as diverse and dynamic. In particular, improved tools, methods, and applications are constantly appearing on the market and in scientific research. It should be noted that practically any compound in a solid, semi-solid, or liquid state can be analyzed and characterized by thermal analysis (TA) methods. In recent years, integrated (synchronous) devices have begun to appear that combine several methods for analyzing the conversion of matter with automation and using the capabilities of modern computers in a single approach. In this chapter, we will consider the features of the basic methods used to study the kinetics of thermolysis of metal-containing compounds.

Knowledge of the effect of the chemical structure of SSP and the nature of its constituent ions on the efficiency of NP formation provides the possibility of a purposeful change in the functional characteristics of the nanomaterials prepared. At the present time, the problem of the influence of the nature of the chelating ligand on the physicochemical properties and architecture of nanomaterials is being actively studied with a view to predicting possible directions for their application. This problem, like many other problems in the nanomaterial chemistry, it is advisable to investigate based on individual classes of SSPs. In this chapter, we discuss using well-defined and unambiguously characterized metal chelates as SSPs for the preparation of nanomaterials by thermolysis. We are not attempting to give an exhaustive analysis of the entire array of experimental data to date. The main attention will be paid to the specifics of preparing nanomaterials by thermolysis of metal chelates with the most typical and in detail studied ligands.

Solid-state thermolysis of various metal chelates is a simple and rational way of synthesizing new nanostructured materials characterized by a narrow size distribution, low crystal defects, and controlled forms.

A common drawback of practically all methods for obtaining metal–polymer nanocomposite materials with “core–shell” structure is the multistage of process, on the one hand, and the formation of polydispersed systems with a wide distribution of particle size, on the other hand. Traditional approaches are rather laborious and include the stage of formation of macromolecular complexes, metal ions reduction reaction to form nano-sized particles, separation of the phase of chemically unbound components.

In recent years, nanostructured materials (nanocomposites), consisting of a polymer matrix (thermoplastic, thermosets, or elastomers), filled with small amounts of metal or metal oxide NPs, have attracted the considerable attention of researchers. Organic matrix, i.e., polymer, forms the basis of such nanocomposites, while NPs are dispersed in the polymer matrix and have a significant and unique influence on its macroscopic properties and are also able to interact with the polymer matrix at the molecular level. It is known that the combination of the advantages of simple processing and structural flexibility of polymers with optical properties and stability provided by inorganic material has strong synergistic effects.

Nanomaterials obtained by thermolysis of metal chelates are widely used in many promising areas: from catalysis and sensing to energy storage [1–42]. This is achieved by easy fabrication of NPs obtained from metal chelates and other properties, including a large active surface area, optimized porosity, size selectivity, and controlled texture and composition, as well as high photocatalytic activity, high adsorption capacity, good electrocatalytic activity, and outstanding electrochemical performance.