The role of growth directors in controlling the morphology of hematite nanorods

DOI: 10.1186/s11671-020-03387-w

Authors: Christopher J. Allender (CMD Ltd) , Jenna L. Bowen (CMD Ltd; Cardiff University) , Veronica Celorrio (Diamond Light Source) , Josh A. Davies-jones (Cardiff University) , Philip R. Davies (Cardiff University) , Shaoliang Guan (Cardiff University) , Padraic O’reilly (Molecular Vista) , Meenakshisundaram Sankar (Cardiff University)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Nanoscale Research Letters , VOL 15

State: Published (Approved)
Published: August 2020
Diamond Proposal Number(s): 15151

Abstract: The control of the growth of hematite nanoparticles from iron chloride solutions under hydrothermal conditions in the presence of two different structure promoters has been studied using a range of both structural and spectroscopic techniques including the first report of photo induced force microscopy (PiFM) to map the topographic distribution of the structure-directing agents on the developing nanoparticles. We show that the shape of the nanoparticles can be controlled using the concentration of phosphate ions up to a limit determined to be ~6 × 10−3 mol. Akaganéite (β-FeOOH) is a major component of the nanoparticles formed in the absence of structure directors but only present in the very early stages (< 8 h) of particle growth when phosphate is present. The PiFM data suggest a correlation between the areas in which phosphate ions are adsorbed and areas where akaganéite persists on the surface. In contrast, goethite (α-FeOOH) is a directly observed precursor of the hematite nanorods when 1,2-diamino propane is present. The PiFM data shows goethite in the center of the developing particles consistent with a mechanism in which the iron hydroxide re-dissolves and precipitates at the nanorod ends as hematite.

Subject Areas: Chemistry


Instruments: B18-Core EXAFS

Documents:
s11671-020-03387-w.pdf