Temperature driven in-situ phase transformation of PbWO₄ nanobelts

Abstract

Monoclinic raspite PbWO₄ nanobelts were synthesized by a facile composite-salt-mediated method. By in situ heating to above 538 °C inside the chamber of a transmission electron microscope, the raspite nanobelts transformed irreversibly to tetragonal scheelite phase. By analyzing the experimental data, three possible topotactic transformation relationships between raspite and scheelite phases have been proposed. With further increasing the temperature up to 618 °C, part of the PbWO₄ nanobelts reduced to tetragonal WO₃ nanorods owing to the evaporation of Pb.