Title: A greener approach to the solution combustion synthesis of mixed oxides: Role of the chemical precursors

Abstract

Nowadays, advanced materials production needs to rely on sustainable synthesis procedures. In order to be sustainable, a synthesis procedure should be (I) efficient (cost-saving, energy saving, time-saving), (II) eco-friendly, (III) scalable, (IV) reproducible and (v) beneficial for environment, society and economy. Solution combustion synthesis (SCS) is a well known chemical methodology for the powerful and versatile preparation of mixed oxides, based on the self-sustaining redox reaction between fuel and oxidant in the presence of metal precursors. SCS satisfies most of the sustainability requirements cited above, although not all of them. In fact, a greener approach is necessary in order to call this methodology as sustainable. This mini-plenary presentation highlights the steps towards a greener approach to SCS, from the chemical precursors to the materials application. The first step is the use of waste-derived resources for fuels or metal precursors. A further step is an improvement in efficiency, scalability and reproducibility of SCS, which is possible only through a profound knowledge of the relationships between synthesis parameters and final properties of the obtained materials. In this respect, the chemical composition of the material plays an important role and it should be taken into account during optimization of the synthesis parameters. The use of several complementary characterization tools is highly recommended, for a deeper understanding of all the effects caused by the synthesis parameters. Finally, the applicability of the material for the benefit of the environment (I.e. pollution control; waste re-use), society (i.e.: clean water, clean air or clean energy production/accumulation) and economy (i.e.: circular economy; higher efficiency of the industrial synthesis processes) fulfills the last requirement. All these considerations refer to SCS, although most of them can be easily extended to other chemical methodologies for the preparation of mixed oxides.