Gas-Solution interfacial synthesis of porous zinc layered hydroxide film and in-situ silver intercalation for enhanced photocatalytic activity

The work focuses on developing eco-friendly “soft” chemistry techniques. Thus, perforated nanosheets can be prepared at room temperature by interfacial interactions. A reaction between ethylenediamine (EDA) vapor and zinc cations in zinc salt aqueous solution produced a thin solid film of zinc-layered hydroxide salts (ZnLHS) on the solution surface. The composition, crystalline structure and morphology of the film were controlled by hydrochemical equilibrium in aqueous solution and depended on the precursor salt. The conditions were identified under which ZnLHS hierarchical porous films were formed at the solution-gas interface. Pores of about 50 nm in size occurred due to dissolution of an intermediate compound. Decomposition caused by heat treatment resulted in the formation of voids up to 10 μm in size. The layered structure of the synthesized film had an interlayer spacing of 2 nm allowing intercalation of silver ions. ZnAg0LHS composite film was obtained which contained Ag nanoparticles of 2–3 nm in size and demonstrated high photocatalytic activity in the decomposition reaction of the methylene blue aqueous solution. This facile synthesis method of hierarchical-porous films is promising for the design of new materials for sensors, biomedicine, and environmental applications.