Back to basics: synthesis of metal oxides

Synthesis of metal oxides is typically the first step of any materials science research in a field or application involving oxides materials. However, the synthesis is rarely the prime focus in materials science, which usually describe properties and characterizations of said materials. Consequently, synthesis protocols are often given too little attention in the literature and hence poorly described. For scientists starting in the field, it becomes confusing to make the right choice of synthesis route and conditions to successfully prepare what will be the base of their research, which is a pure, single phase, complex oxide powder. With this tutorial article, we are giving basic knowledge on the underlying chemistry of oxide synthesis, and simple explanations on what motivates the need of various synthesis routes. Then, four main synthesis routes are described, namely the solid state reaction route, the Pechini route, the combustion route, and the precipitation route. For each routes, the approach is described, and the relevant parameters to be considered are developed. Finally, a step by step general protocol for each route is proposed, which can serve as a solid foundation for unexperienced researchers to become more confident when approaching metal oxide synthesis.