(NH4)2S, a highly reactive molecular precursor for low temperature anion exchange reactions in nanoparticles

Haitao Zhang; Louis V Solomon; Don-Hyung Ha; Shreyas Honrao; Richard G Hennig; Richard D Robinson

doi:10.1039/c3dt50803j

(NH4)2S, a highly reactive molecular precursor for low temperature anion exchange reactions in nanoparticles

Dalton Trans. 2013 Sep 21;42(35):12596-9. doi: 10.1039/c3dt50803j.

Authors

Haitao Zhang¹, Louis V Solomon, Don-Hyung Ha, Shreyas Honrao, Richard G Hennig, Richard D Robinson

Affiliation

¹ Department of Materials Science and Engineering, Cornell University, Ithaca, NY 14853, USA.

PMID: 23779083
DOI: 10.1039/c3dt50803j

Abstract

Ammonium sulfide ((NH4)2S) exhibits high reactivity as a sulfide reagent in anion exchange reactions that transform CoO to cobalt sulfide nanoparticles (NPs). The faster diffusion of Co(2+) and O(2-) than the incoming S(2-) during the anion exchange causes a significant expansion of the NP voids. The low temperature (70 °C) anion exchange reaction produces amorphous cobalt sulfide NPs with Co : S ratio of ca. 3 : 4, which are converted into crystalline NPs with a major phase of cubic Co3S4 by annealing at high temperature in an organic solution.