Facet-controlled growth and soft-chemical exfoliation of two-dimensional titanium dioxide nanosheets

Abstract

TiO2 remains as one of the most popular materials used in catalysts, photovoltaics, coatings, and electronics due to its abundance, chemical stability, and excellent catalytic properties. The tailoring of TiO2 structure into two-dimensional nanosheets prompted the success of isolation of graphene and MXenes. In this review, facet-controlled TiO2 and monolayer titanate are outlined, covering their synthesis route and formation mechanism. The reactive facet of TiO2 is usually controlled by capping agent. In contrast, the monolayer titanate is achieved by ion-exchange and delamination of layered titanates. Each route leads to 2D structures with unique physical and chemical properties, which expands its utilisation into several niche applications. We elaborate the detailed outlook for future use of, and research into, facet-controlled TiO2 and monolayer titanates. The advantages and disadvantages of both structures are provided along with suggested applications for each type of 2D TiO2 nanosheets.