Facile preparation of Bi nanoparticles by novel cathodic dispersion of bulk bismuth electrodes

A novel electrochemical approach has been developed to prepare clean bismuth nanoparticles (NPs) with a bulk Bi electrode in a 0.5 mol dm−3 NaOH solution under highly cathodic polarization of −8 V versus a saturated mercurous sulfate electrode, requiring no any precursor ions and organic protective agents. The bulk Bi electrode can be facilely dispersed into Bi NPs at the condition of intensive hydrogen evolution. This cathodic dispersion of the bulk Bi electrode involves the formation and decomposition of unstable bismuth hydrides and the aggregation of atomic bismuth from the decomposition. Moreover, Bi2O3 NPs have also been achieved by heating the precursor Bi NPs. Field-emission scanning electron microscopy, transmission electron microscope and X-ray diffraction were used to characterize these NPs. The as-prepared Bi NPs mainly existed in rhombohedral phase.