Hydrothermal synthesis is a solution reaction based approach. In a broader sense, it can be defined as the method for making materials from room temperature to high-temperature solutions. To control the morphology of the materials to be prepared, either low pressure or high pressure conditions may be used depending on the vapor pressure of the main composition in the reaction. Many types of nanomaterials have been successfully synthesized by the use of this approach. There are significant advantages of hydrothermal synthesis method over others. Hydrothermal synthesis can generate nanomaterials which are not stable at elevated temperatures. Nanomaterials with high vapor pressures can be produced by the hydrothermal method with minimum loss of materials. The compositions of nanomaterials to be synthesized can be well controlled in hydrothermal synthesis through liquid phase or multiphase chemical reactions.

This special issue serves as a forum presenting the recent research results of hydrothermal synthesis of nanomaterials. Research and review papers on hydrothermal synthesis of nanoparticles, nanofibers/tubes/ribbons/wires, and nanoplatelets fall into the scope of this special issue. Research works on the low cost and scalable synthesis of new nanomaterials for energy and environmental sustainability challenge are particularly welcome.

Potential topics include but are not limited to the following:

• New nanomaterials growth by hydrothermal method
• Hydrothermal process control and simulation
• Hydrothermal precipitation of nanoparticles
• Hydrothermal spraying and injection thin films
• Hydrothermal synthesis under ambient conditions including sol-gel deposition
• Characterization of hydrothermal synthesized nanomaterials
• Morphology and structure analysis of hydrothermal synthesized nanomaterials
• Applications of hydrothermal synthesized nanomaterials for solving energy, environmental, and biomedical problems