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This work focuses on the synthesis of Bi2Fe4O9/Ag3PO4composites with different Bi2Fe4O9contents to remove the Rhodamine B (RhB) dye pollutant. The obtained composites were characterized by scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, Photoluminescence and UV–Vis spectrophotometry. The 5Bi2Fe4O9/Ag3PO4catalyst with 5% Bi2Fe4O9loading exhibited the high photocatalytic performance with degradation efficiency of 97.91% after 12 min under visible light irradiation. Photoluminescence and UV–Vis analysis showed that 5Bi2Fe4O9/Ag3PO4has the best separation of photogenerated e−/h+pairs and light absorption. The catalyst exhibited a good selectivity toward tartrazine and methylene blue. The cycling experiment revealed that 5Bi2Fe4O9/Ag3PO4catalyst has a good stability after 4 runs. The results of trapping radical experiments indicated that h+charge carriers were the main species involved in the RhB photodegradation process which was supported by a Z-scheme electron transfer mechanism.

The electrodeposition of Ni–Co–TiO2composite coatings on XC70 mild steel was investigated using the chronoamperometry method. This technique allowed the co-electrodeposition of titanium dioxide (TiO2) nanoparticles with the Ni–Co alloy, from stirred solutions containing very low TiO2concentrations. To determine the range of deposition potential, linear sweep voltammetry and chronopotentiometry experiments were carried out. The effect of TiO2nanoparticles on the surface properties was evaluated from the point of view of their morphology, composition, structure, wettability, and corrosion resistance. The deposited coatings were analyzed using Focused Ion Beam (FIB) coupled with scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), atomic force microscope (AFM), contact angle measurements, and microhardness tests. The corrosion behavior of the pure Ni–Co alloy and Ni–Co–TiO2nanocomposites was assessed by weight loss method, potentiodynamic polarization tests and electrochemical impedance spectroscopy (EIS) in 3.5 % NaCl solution. The corrosion performance of the composite coatings improved with increasing TiO₂ concentration, reaching a maximum at 0.64 %. Ni–Co–TiO2coatings exhibited more positive Ecorrvalues and lower icorrthan the pure Ni–Co alloy. The addition of 0.64 % TiO₂ increased the microhardness of the pure Ni–Co deposit by 170 HV0.05and raised the surface roughness from 170 nm to 428 nm. Furthermore, the contact angle increased from 80° to 125°, corresponding to a more hydrophobic surface and hence a better durability in corrosive environments.