Synthesis of TiO₂ Materials Using Ionic Liquids and Its Applications for Sustainable Energy and Environment

Titanium dioxide (TiO₂) has received significant attention because of the global climate change and the consumption of fossil fuel resources. Specifically, using TiO₂ in photocatalytic applications, such as the removal of organic pollutants and a hydrogen production has become an important issue. Thus, many researchers have attempted to prepare highly active TiO₂ materials using various synthetic approaches. Modifications of the conventional sol–gel method, such as the addition of surfactants, have been employed in synthetic procedures. Moreover, hydrothermal, solvothermal, sonochemical and microwave methods have also been used as alternative approaches. Recently, the use of ionic liquids represents a burgeoning direction in inorganicmaterial synthesis. Ionic liquids are exceptional solvents consisting of ions possessing low vapor pressure and tunable solvent properties. This article reviews the preparation of TiO₂ materials using ionic liquids with various synthetic approaches. Also, sustainable energy and environmental cleanup applications of TiO₂ materials, including the treatment of hazardous organic substances and hydrogen energy derived from electrochemical methods, are discussed.