Lead citrate precursor route to synthesize nanostructural lead oxide from spent lead acid battery paste

Nanostructural lead oxides were prepared by the decomposition of a new type of lead citrate precursor (Pb3(C6H5O7)2·3H2O), which was synthesized through leaching of spent lead acid battery paste in citrate salt aqueous system and more economical compared with former precursor (Pb(C6H6O7)·H2O). The products were characterized by thermogravimetric–differential thermal analysis, scanning electron microscopy and X-ray diffraction. The results show that when lead citrate of columnar-shape crystals are calcined in N2 gas, orthorhombic β-PbO is the main product containing small amount of Pb and C. On combusting the citrate in air, a mixture of orthorhombic β-PbO, tetragonal α-PbO and Pb with the particle size of 100–200 nm is obtained, with β-PbO as the major product. And the cyclic voltammetry measurements of lead oxides present different electrochemical redox potentials because of the different structure of lead oxide obtained from Pb3(C6H5O7)2·3H2O.