Green fabrication of 3-dimensional flower-shaped zinc glycerolate and ZnO microstructures for p-nitrophenol sensing

The solvent or reaction medium always plays a lead role in synthesis chemistry. Glycerol has been studied as a green solvent for different organic transformations and is also expected to give interesting control in material synthesis. In this study, we use aqueous glycerol to synthesize zinc glycerolate and the corresponding ZnO micro-flower structures with an intention to encourage the utilization of glycerol as a green reaction medium in material synthesis. A zinc ammonium complex is used as a source of zinc, which converts to zinc glycerolate in the presence of glycerol. Glycerol plays a dual role as a reactant to form zinc glycerolate and as a solvent to control the morphology. The unreacted glycerol is recovered after the reaction and reused further. The flower-structured zinc glycerolate and ZnO are then used for the first time to modify a glassy carbon electrode to make a binder-free non-enzymatic amperometric chemical sensor for p-nitrophenol that is a brutal environmental pollutant. The modified electrode is found to be an excellent alternative for the purpose with respect to sensitivity, selectivity and stability.