This study investigates the surface area, optical characteristics, adsorption behavior, and photocatalytic performance
of graphite (G), copper oxide (CuO), iron oxide (Fe₂O3), and CuO/Fe₂O3 nanoparticles (NPs), as well as
their modified nanocomposites (NCs): CuO/G (denoted as Cu/G), Fe₂O3/G (Fe/G), and CuO/Fe₂O3/G (CuFe/G).
The co-precipitation method was used for NPs synthesis, whereas NPs/G are synthesized via the hydrothermal
method. The samples are characterized using XRD, SEM, and BET analyzers, and tested using optical, adsorption,
and photocatalytic measurements. The structural analysis confirmed hexagonal, monoclinic, and rhombohedral
structures for G and NPs along with mixed phases for NCs. Graphite (G) exhibits the highest porosity (PS) among
all tested materials, while incorporating G enhanced the PS of the NCs. The G structure was confirmed by wellstacked
graphene sheets. The NPs adopted a regular or irregular spherical shape, whereas the NCs formed larger
aggregates consisting of multiple NPs. The G exhibited the highest surface area (SA) at all, whereas the NPs
exhibited the lower values. However, incorporating G into NPs enhanced the SA, with the highest value for Cu/G
among NCs. Notably, pure NPs exhibited two distinct electronic transitions and corresponding energy gaps (Eg1
and Eg2), whereas the other samples displayed only a single transition with a unique Eg. Regardless of the Eg2
for NPs, the Eg is 2.2 eV for G, whereas the NPs and NCs generally demonstrated reduced Eg, spanning
1.45–2.45 eV. Graphite demonstrated the highest photocatalytic efficiency (η) of 68.78 % after 300 min, but it
decreased to 41.90 and 39.67 % for NPs and then increased for all NCs, with Cu/G reaching 61.02 %. The CuFe/G
NCs showed the highest removal efficiency of 53.69 % after 420 min, followed by Cu/G NCs (51.87 %), which
are better than those of G and NPs. The proper model for CuFe/G NCs is pseudo-2nd-order, but it changed to
pseudo-1nd-order for the other samples. These outcomes collectively demonstrate that graphite modification
provides a versatile approach to engineering composite materials with simultaneously enhanced properties
convenient for optoelectronic and water treatment applications.