Enhance methanol-sensing properties based on Ag functionalized monolayer LDH nanosheet: A combined experimental and theoretical calculation investigation

Abstract

Layered double hydroxides has been greatly explored for gas sensor applications due to their highly tunable chemical composition and unique layer structure. In this work, an investigation combined experimental and theoretical on Ag functionalized monolayer ZnAl-LDH (Ag/LDH) is performed for excellent methanol sensing performance. The monolayer ZnAl-LDH nanosheets was firstly prepared via an inverse-microemulsion method to reduce the stacking of LDHs. Then Ag nanoparticles (NPs) were successfully introduced on the surface of monolayer LDH by glucose reduction method. The Ag/LDH nanocomposite shows Ag NPs uniformly attached on the monolayer LDH nanosheet with large specific surface area. Benefiting from the unique microstructure of monolayer LDH and Ag functionalization, the Ag/LDH gas sensor exhibits about 23-fold enhancement in response value to 25 ppm methanol at room temperature compared with multilayer LDHs sensor. Meanwhile, the as-prepared sensor can detect 500 ppb methanol and exhibits extremely fast response-recovery characteristics upon 10–200 ppm methanol. Further gas adsorption calculations based on first principles were performed to clarify the key contribution of Ag NPs to methanol adsorption and the corresponding gas mechanism is also proposed. Above all, the present work indicates that the functionalization of Ag NPs is highly potential for enhancing the response LDH towards methanol vapor. • Combination of experiment and first-principles calculations. • Monolayer LDH nanosheets with uniformly attached Ag NPs were prepared. • The Ag/LDH sensor shows rapid response and recovery characteristic to methanol at room temperature. • The as-fabricated gas sensor could detect as low as 500 ppb methanol with a response of 3.35% at room temperature.