Versatile inorganic-organic hybrid WOx-ethylenediamine nanowires: Synthesis, mechanism and application in heavy metal ion adsorption and catalysis

Inorganic-organic hybrid WOx-ethylenediamine (WOx-EDA) nanowires have been produced by a simple, low-cost and high-yield solvothermal method. These WOx-EDA hybrid nanowires have unique lamellar mesostructures with an alternate stacking of an interconnected [WO6] octahedral layer and a monolayer of ethylenediamine molecules. This hybrid structure integrated the functionality of ethylenediamine with the stability of the WOx frameworks. In situ synchrotronradiation X-ray diffraction is used to elucidate a possible formation mechanism of the hybrid WOx-EDA. The nanowire morphology, lamellar structure and abundant functional amino groups endow them with versatile abilities. For example, in heavy metal ion adsorption the WOx-EDA nanowires display exceptional adsorption capabilities of 925 mg·g-1 for Pb2+ and 610 mg·g-1 for UO22+. The nanowires also show outstanding stability and activity as a heterogeneous base catalyst in the Knoevenagel condensation reaction at room temperature. The catalyst can be recycled and reused for 20 cycles with nearly 100% yields. This study provides a new strategy to design inorganic-organic hybrid materials, and offers a multifunctional material that is a highly efficient adsorbent and sustainable catalyst.