Table of Contents
Journal of Theoretical Chemistry
Volume 2014 (2014), Article ID 312921, 7 pages
http://dx.doi.org/10.1155/2014/312921
Research Article

Ab Initio Studies on Hematite Surface and the Adsorption of Phosphate

1Raman Centre for Applied and Interdisciplinary Sciences, 16A Jheel Road, Kolkata, West Bengal 700075, India
2Department of Agricultural Chemistry and Soil Science, University of Calcutta, 35 BC Road, Kolkata, West Bengal 700019, India

Received 4 March 2014; Accepted 7 September 2014; Published 28 September 2014

Academic Editor: Jorge M. Seminario

Copyright © 2014 Swati Chaudhury et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

This investigation explores the ab initio DFT method for understanding surface structure of hematite and the nature and energetics of phosphate adsorption. Using the full potential linearized plane wave method (FP-LAPW), we derived the structure and energies of various magnetic forms of hematite. The antiferromagnetic (AFM) form was observed to be the most stable. Hematite surfaces with Fe-termination, O-termination, or OH-termination were studied. The OH-terminated surface was the most stable. Stability of hematite surfaces follows the order OH-termination > Fe-termination > O-termination. Thus, surface reaction with hematite would occur with the OH at the surface and not with Fe atoms. The structure of phosphate adsorbed on hematite was derived. Bonding is through the H atom of the OH at the surface. An alternative mechanism of phosphate adsorption on hematite has been derived. Adsorption energy is high and suggests chemisorption rather than physisorption of phosphate on hematite.