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A part from the broad peak due to PVA, low intensity peaks at 2θ values 26.5 º and 43.8 º corresponds to (111), (220) lattice planes of cubic β CdS respectively (JCPDS card no.10-454) has been observed [9].
Ne=N∞1-e-t/τ (5) Where Ne is the number of electron being released from trap states and reaching conduction band, N∞the value for infinite time, τ is effective time constant for recombination of charge carrier.

According to previously published literature, the diffraction peaks from the data at the same 2Ɵ values coincide well with the standard data of the joint committee on powder diffraction standard (JCPDS), Card No: 00-006-0464 [12, 39, 40].
Acknowledgment This work was funded by the Researchers Supporting Project Number (RSPD2024R763) King Saud University, Riyadh, Saudi Arabia.

The sites and the intensity of the obtained diffraction peaks were agreeable with the values reported for bulk magnetite from the JCPDS card No. 89-0691.
Other occupants within this structure are tetrahedral Fe3+ and equal number of octahedral Fe2+ and Fe3+ cations, with the total ratio of 1:2.

The samples synthesized at 30°C has shown large number of additional peaks indicating high impurity nature of the powder, whereas the temperature 60°C has been resulted crystalline pure ZnO .
The spacing values and relative intensities of the peak coincide with the JCPDS Card No. 36-1451for ZnO powder.

Among the large number of semi-conductors catalysts, TiO2 catalyst has been experimented due to these advantages, such as stable chemical properties, low cost, non-toxicity and slight solubility [7].
At 450 oC, the product is the pure phase triclinic FeVO4, whose diffraction peak is consistent with the XRD physical phase Standard Card (JCPDS No.38-1372).

Using the lattice parameter of 8.384 Å in FeO·Fe2O3 (No. 28-664 according to the JCPDS card index) and in lithium spinel 8.367 Å, we obtain the equation: 8.384×С* + 8.367×(1-С) = 8.372, where C is the amount of formed Fe2+ ions.
To ensure a change in the valence of such a number of iron cations, ~ 5 % of oxygen atoms must evaporate.

XRD peaks in the angle of (2θ) 38.14°, 44.29°, 64.48°, 77.38° can be attributed to facets 111, 200, 220, 311 respectively of the face-centered cubic crystal structure that accorded with the standard silver card values (JCPDS No. 87-0720) [36].
The decline in the size of the metal nanoparticles contributes to the rise in the number of the coordinate atoms and enhances the adsorption of the reactants on the surface of the catalyst and thus leading to the increase in the reaction rate [39].

Furthermore, the diffraction pattern of the sample is in accordance with the standard diffraction pattern of ZnFe2O4 nanoparticles (JCPDS card No. 22-1012) with a cubic spinel structure.
As the contact time increases, the amount of adsorbate that interacts with the active sites of the adsorbent increases, while the number of active sites that can be filled by Pb2+ ions decreases.

A brief comparison with the standard card for graphite (JCPDS No. 41-1487) reveals a high degree of similarity, affirming the desired graphitic characteristics of the produced carbon material [15].
Acknowledgment This research is funded by Le Quy Don Technical University Research Fund under the grand number “2023.QHT.02”.

Graphene was used as a conductive matrix to support CuxS NPs for providing a faster electrons transfer rate and larger number of active sites for the electrolyte reduction.
All the obtained diffraction peaks in the pattern are well matched with the hexagonal covellite phase of cupric sulfide (JCPDS Card No. 00-006-0464).