An overview into advantages and applications of conventional and unconventional hydro(solvo)thermal approaches for novel advanced materials design

The hydro(solvo)thermal approaches due to their simplicity and relatively low cost have attracted great attention to novel advanced materials processing with controlled particle sizes and well-defined morphologies, including the desirable obtaining of diverse metastable phases. Furthermore, in this case, such advanced materials obtained by this strategy generally have a high crystallinity structure as the main characteristic, which is interesting for a wide range of technological applications of high performance. This critical review presents the recent progress and challenges in conventional and unconventional hydro(solvo)thermal synthesis of novel advanced materials with desirable functionality and outstanding physicochemical properties designed using such methods. We intend to highlight the preparation of different hierarchical structures, such as: (i) hollow spheres and porous structures; (ii) one-dimensional (1D) materials (such as tubes, wires, and rods); (iii) two-dimensional (2D) materials; and (iv) heterostructured materials (such as decorated, Janus-like, core–shell, and yolk–shell). The choice of these nano/microstructures is based on their promising properties for many emerging applications ranging from optoelectronics to the photo-electro-chemical catalytic field. New chemical insights on the rational design of new advanced materials can also be achieved through detailed knowledge of the effect of processing parameters and how they will affect the structure-composition-morphology of prepared materials. Finally, in this perspective, we believe that this detailed knowledge of the effect of processing parameters and as they will affect the prepared materials structure-composition-morphology is a key step to providing new chemical insights for the rational advanced materials design.