Fabrication of Zinc pyrovanadate (Zn3(OH)2V2O7·2H2O) nanosheet spheres as an ethanol gas sensor

It is necessary to conveniently and quickly detect the concentrations of ethanol in different environments. A new type of zinc pyrovanadate (Zn3(OH)2V2O7·2H2O) nanosheet spheres is obtained by a convenient single cation-exchange process using sodium vanadate (Na5V12O32) nanowires as precursor, without introducing any surfactant as a catalyst or structure-directing agent. During the exchange of Zn2+ and Na + ions, the Na5V12O32 nanowires gradually transfer to Zn3(OH)2V2O7·2H2O nanosheet spheres along with dissolution of the precursor and precipitation of new nanosheets. The synthetic mechanism of Zn3(OH)2V2O7·2H2O nanosheet spheres is studied by examining the changes of morphological properties of intermediate products at different times. Gas sensors based on these Zn3(OH)2V2O7·2H2O nanosheet spheres are tested. The sensor displays a response value of 1.68–100 ppm concentration of ethanol gas, and reveals a relatively high sensitivity at a relatively low optimal operating temperature of 300 °C, as well as relatively good stability.