Behavior of sheet-like crystalline ammonium trivanadate hemihydrate (NH4V3O8×0.5H2O) as a novel ammonia sensing material

• A simple hydrothermal method for the fast synthesis of trivanadate hemihydrate (NH4V3O8×0.5H2O) is reported.
• Sheet particles could be obtained.
• A preliminary demonstration of the feasibility of using NH4V3O8×0.5H2O as a novel ammonia sensing material is presented.

This work reports the use of ammonium trivanadate hemihydrate (NH4V3O8×0.5H2O) as a novel sensing material for ammonia resistive sensors. It was prepared by a simple and fast hydrothermal method from V2O5 as a precursor and characterized by SEM, FT-IR, XRD and TG techniques. The as-synthesized material showed a sheet-like morphology and was found thermally stable up to 250–280 °C. It reacted promptly and irreversibly when exposed to ammonia at room temperature. A full reversibility was instead registered undergoing the formed ammonia adduct at a temperature higher than 200 °C.A NH4V3O8×0.5H2O-based resistive gas sensor was fabricated and its sensing properties were evaluated. Experimental results obtained have given a preliminary demonstration of the feasibility of using NH4V3O8×0.5H2O as a novel ammonia sensing material since it yields several advantages including easy synthesis of the sensing layer, good sensitivity and reproducibility and fast response.

Sheet-like morphology of the synthesized trivanadate hemihydrate (NH4V3O8×0.5H2O). Inset: Its electrical response to different ammonia concentrations in air.Figure optionsDownload as PowerPoint slide