New developments in the nonaqueous and/or non-hydrolytic sol–gel synthesis of inorganic nanoparticles

The development of nonaqueous and surfactant-free sol–gel routes to metal oxides has become a very active area within the broad field of nanoparticle research, opening up great opportunities to access a wide variety of binary, ternary and doped metal oxide nanoparticles with high crystallinity and well-defined particle morphologies — important parameters towards their application in electrochemistry, (photo)catalysis or gas sensing. Extension to other classes of inorganic nanomaterials such as nitrides and sulfides and energy optimization of the processes by using dielectric heating represents two promising research directions. Remaining future challenges are not only the development of rational synthesis strategies, nanoparticle processing, assembly and patterning into functional and integrated structures, but also the optimization of the synthesis protocol with respect to energy efficiency and waste management. This review aims at giving both an overview of the current state of research as well as a discussion of the perspectives in the area of nonaqueous and/or non-hydrolytic sol–gel technology for the synthesis, processing and application of inorganic nanomaterials.