Large-scale aqueous synthesis of layered double hydroxide single-layer nanosheets

Inorganic layered double hydroxide (LDH) single-layer nanosheets (SLNSs) are traditionally synthesized with the assistance of organic chemicals or in organic solvents, resulting in organic-coated SLNSs or organic dispersions of SLNSs, which may limit their potential applications. Herein, we report, for the first time, a simple aqueous synthetic route to naked (uncoated) LDH SLNSs; this route, which is termed the PWD route for simplicity, includes three steps: aqueous coprecipitation, water-washing, and redispersion in water. The obtained LDH SLNSs were characterized using TEM, AFM, XRD, and dynamic light scattering techniques, and the stability of the LDH SLNS dispersions was determined. Moreover, the co-assemblies of the LDH SLNSs with negatively charged guests, sodium cholate and graphene oxide, were investigated. Results showed that the SLNSs can remain stable (i.e., without layer-by-layer stacking) for a period of time, depending on temperature, and can be directly used as building blocks for functional materials. This new route has many advantages including its simple operation, environmental friendliness, low cost, and ease of large-scale application. (c) 2016 Elsevier B.V. All rights reserved.