Transition metal dichalcogenides (TMDCs), represented by MX₂ (where M = Mo, W and X = S, Se, and Te), and more recently, their moiré superlattices (i.e., formed by superimposing layers of TMDCs with different rotation angles) have attracted considerable interest due to their excellent physical properties and unique nanoscale functionalities. Compared to graphene, the literature indicates that TMDCs offer a competitive advantage in optoelectronic technologies, primarily owing to their compositionally controlled non-zero bandgap. These two-dimensional (2D) nanostructured single or multiple layers exhibit remarkable properties that differ from their bulk counterparts. Moreover, stacking different TMDC monolayers also forms heterostructures and introduces unique quantum effects and extraordinary electronic properties, which is particularly promising for next-generation optoelectronic devices and photo(electro)catalytic applications. Therefore, in this review, we also highlight the new possibilities in the formation of 2D/2D heterostructures of MX₂-based materials with moiré patterns and discuss the main critical challenges related to the synthesis and large-scale applications of layered MX₂ and MX₂-based composites to spur significant advances in emerging optoelectronic and photo(electro)catalytic applications.

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. 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.