Preparation of γ-Fe₂O₃/Ni₂O₃/FeCl₃(FeCl₂) Composite Nanoparticles by Hydrothermal Process Useful for Ferrofluids

Table 3

Binding energy data from XPS (eV) for the precursor (a) and the processed sample in 0.25 M (b), 0.50 M (c), and 1.00 M (d) FeCl₂ solution.

	Fe2p	Ni2p	O1s	Cl2p
(a)	711.15	855.81	530.75
FeO*O**H	711.40		*530.10; **531.20
Ni(OH)2		855.80	531.50
(b)	710.83	855.25	530.16	198.78
(c)	710.90	855.39	530.27	198.82
(d)	710.97	855.25	530.23	198.85
γ-Fe2O3	710.90		529.80
Ni2O3		855.60	531.80
FeCl3/FeCl2	711.10/710.40			198.80/198.60

Note: the standard data for FeO*O**H, Ni(OH)₂, γ-Fe₂O₃, Ni₂O₃ and FeCl₃ are taken from PHI 5300 ESCA Data Bank and the Handbook of X-ray Photoelectron Spectroscopy.