Formation Of Copper Oxide Research Articles

Distinctive Effects of Surface Roughness and Ions Release on the Bacterial Adhesion and Inactivation of Textured Copper Oxide Surfaces

In this manuscript, we studied the effect of additive manufacturing pretreatment on bacterial adhesion and inactivation on copper-based interfaces. Sandblasting, mirror polishing and Surface Mechanical Attrition Treatment (SMAT) at high or low energies have been employed to modify the substrate’s (316L stainless steel) roughness. The pretreated substrates were coated with thin copper films using magnetron sputtering. The thin copper films’ composition and antibacterial activities were first optimized by being deposited on an Si wafer. We showed that the surface roughness profile influenced bacterial adhesion in the dark. Bacterial inactivation was monitored under indoor light. Stereomicroscopy imaging showed live/dead bacterial cells on the coated substrates. Scanning electron microscopy (SEM) showed homogeneous coating growths of copper with a columnar texture. The chemical composition of the deposited Cu thin films was carried out by Energy Dispersive X-ray Spectroscopy (EDX) and showed a uniform distribution of copper and oxygen, revealing the formation of copper oxides (CuxO). The oxygen content of the sputtered films varied from 7.8 to 25%, justifying the semi-conductor behavior of the thin films under indoor light. The crystallographic structure of the sputtered thin films was investigated using X-ray diffraction (XRD), showing the cubic Cu peaks and characteristic peaks of Cu2O. The Cu peaks at 2θ values of 43.28°, 50.40° and 74.81° were attributed to the (111), (200) and (220) planes, respectively. The use of genetically modified bacteria (without porins) allowed the rationalization of the predominant effect of the extracellular bacterial inactivation compared to that of intracellular bacterial inactivation through ion release and diffusion.

Synthesis of CuO thin films by a direct current reactive sputtering process for CO gas sensing application

A direct current magnetron reactive sputtering, one of the well-known physical vapour deposition (PVD) techniques, was employed for the preparation of CuO thin films at room temperature for CO gas sensing application. The effect of the O2 gas flow ratio on the phase formation of copper oxide was studied by varying the O2 flow rate in the total flow of Ar/O2 gas mixture. Cu2O phase was found to form at a low O2 flow ratio of 10% and gradually converted into stable CuO phase with an increase in O2 flow ratio through the intermediate phase of Cu4O3. The films exhibited a granular morphology, and the average grain size increased with an increase in the O2 partial flow. Single-phase CuO thin film has been obtained with 40% of O2 gas flow ratio. The evolution of the copper oxide phases with increasing O2 partial flow was also confirmed using the Cu 2p and O 1s core-levels of X-ray photoelectron spectroscopy. The CO gas sensing characteristics of the CuO thin film were examined by varying the operating temperature in the range of 200 °C–400 °C. An optimized CO sensing response of 127% has been obtained at 375 °C towards 91 ppm concentration with a response/recovery time of 161 s/99 s.

Dissociative reactions of [Au25(SR)18]- at copper oxide nanoparticles and formation of aggregated nanostructures.

Reactions between nanoclusters (NCs) have been studied widely in the recent past, but such processes between NCs and metal-oxide nanoparticles (NPs), belonging to two different size ranges, have not been explored earlier. For the first time, we demonstrate the spontaneous reactions between an atomically precise NC, [Au25(PET)18]- (PET = 2-phenylethanethiolate), and polydispersed copper oxide nanoparticles with an average diameter of 50 nm under ambient conditions. These interparticle reactions result in the formation of alloy NCs and copper-doped NC fragments, which assemble to form nanospheres at the end of the reaction. High-resolution electrospray ionization mass spectrometry (ESI MS), transmission electron microscopy (HR-TEM), electron tomography, and X-ray photoelectron spectroscopy (XPS) studies were performed to understand the structures formed. The results from our study show that interparticle reactions can be extended to a range of chemical systems, leading to diverse alloy NCs and self-assembled colloidal superstructures.

Investigation of the characteristics of CU2O particles obtained by a plasma-liquid process

PurposeThis paper aims to develop a simple and efficient plasma technology for the production of copper (I) oxide with the ability to control the morphology and size of Cu2O particles. To achieve this goal, the phase composition of the precipitate formed was estimated, the composition and size of the obtained particles were determined and Pourbaix diagrams were constructed.Design/methodology/approachAn integrated approach combining thermodynamic calculations and experimental research methods is used. The constructed Pourbaix diagram makes it possible to suggest the phase composition of the sediment. The use of cyclic voltammetry made it possible to establish the mechanism of deposit formation on the cathode during the treatment of the solution with contact nonequilibrium low-temperature plasma. The resulting product was examined using X-ray phase analysis and scanning electron microscopy.FindingsThe article presents the results of theoretical and experimental studies on the synthesis of copper (II) oxide. The influence of the parameters of plasma-chemical synthesis on the shape and phase composition of the deposits formed has been studied.Originality/valueA plasma-chemical technology for obtaining copper oxide in the form of single crystals of a regular faceted shape is proposed. The mechanism of formation of copper oxide has been established by cyclic voltammetry. The constructed Pourbaix diagrams show the area of existence of the product.

Evaluation of graphene transparent coating on copper for color and oxidation control at low temperatures

In this paper, the ability to preserve copper color was investigated by using graphene thin film coating against oxidation at 200 °C. For this purpose, graphene nano-coating was applied to the copper substrate by using chemical vapor deposition (CVD) process. Raman spectroscopy was used for the detection of the coatings. Structural investigation of the coating was performed before and after oxidation tests using optical and scanning electron microscopes. Color changes due to the formation of copper oxides were calculated using the CIE–L*a*b* color space defined by the Commission Internationale de l'Éclairage (CIE). Furthermore, the reflectance was evaluated in the UV–visible spectrum range. The results revealed that the graphene coated copper had a higher L* than the untreated copper due to the removal of oxide layer during graphene synthesis. The color change (∆E) caused by oxidation at 200 °C, in the graphene coated copper was negligible (∆E = 2.88) after 2 h, and its value was below 5 after 4 h. However, the color change on the bare copper surface was significant (∆E = 26.87) after 15 min of oxidation. The results of the present research show that the graphene coating is effective in protecting copper color. Moreover, since graphene oxidation extends from defects and grain boundaries, synthesis technique plays an important role in protecting copper against oxidation and thus preserving its color.

Laser-based, direct formation of thin copper–nickel alloy films with low thermal coefficient of resistivity

The growing market of printed electronics requires the development of new materials and processing technologies that enable the design of smart wearables, integrated sensors, and next-generation electronics. Against the backdrop of increasing material scarcity, these approaches must be resource-conserving and, at the same time, competitive with conventional technologies. As an alternative to nanoparticle-based inks currently used in printed electronics, another technology has been emerging in the last years that utilizes metal organic decomposition (MOD) inks, which are easy to fabricate and have a long shelf life. In this study, a method is presented that allows the direct formation of thin copper-nickel alloy films from a MOD ink. These alloys are preferably used for sensors like strain gauges as they exhibit a low thermal coefficient of resistivity (TCR). 250 nm thin alloy films are coated on glass substrates and thermally functionalized. In a conventional hot plate heat treatment under a nitrogen atmosphere, 10.2% bulk conductivity for a Cu55Ni45 alloy with a TCR of 8.3 × 10−5 K−1 is reached. X-ray diffraction analysis indicates the formation of a mixed crystal composed of nickel and copper atoms. A laser-based functionalization process is developed that allows the processing of Cu55Ni45 alloy films under ambient conditions without the formation of copper or nickel oxides. Laser-functionalized films exhibit 5.3% of the conductivity of bulk material. This study shows that metal alloy films can be fabricated directly from amine-based MOD inks.

Polyamide powder coating of copper substrates: Impact of process parameters on the surface properties, the adhesion strength and the interface microstructure

The aim of this work was to assess the impact of coating process parameters on the quality of biopolyamide coating on copper substrates obtained by conventional hot dipping fluidized bed coating process (CHDFB). The experiments carried out in this study allowed to understand the decohesion mechanism of virgin biopolyamide 11 before having assessed coating properties by chemical, mechanical and microstructural characterizations. The investigations showed that a higher thickness and better surface finishing were obtained for high preheating temperatures and intermediate immersion times mainly thanks to a higher heat energy stored by the metal support whereas long immersion times compromised the aspect. A laboratory-developed mechanical test was also carried out to determine the adhesion strength. This allowed to overcome the variability linked to the analyzed surface preparation or the local radius of curvature of pull-off and peel conventional adhesion tests respectively that could influence the adhesion strength data. It was concluded that, even if more severe metal preheating conditions improved the coating physical properties, they led to a worse adherence. Surface morphology and spectrometry analyses of the coating side facing the interface correlated to the mechanical test results allowed to highlight the growing formation of copper oxide and copper hydroxide compromising the coating adhesion. From all the results, the optimal process parameters were determined.

Understanding the Catalytic Deactivation upon Hydrothermal Aging at 850 °C of WO3/Fe-Cu-ZSM-5 Catalyst for Selective Catalytic Reduction of NO by NH3

A WO3/Fe-Cu-ZSM-5 catalyst was prepared using the solid state ion exchange method (SSIE) and its performance for the Selective Catalytic Reduction of NO with NH3 (NH3-SCR of NO) was investigated. The study shows that the tungsten addition can slightly improve the high temperature catalytic activity of Fe-Cu-ZSM-5. The influence of hydrothermal aging at 850 °C for 5 h on the structural and textural properties of WO3/Fe-Cu-ZSM-5 was also studied in this paper. The XRD and FE-SEM measurements did not indicate a breakdown of the zeolite structure upon steam treatment for both aged catalysts. The aged W-base catalyst demonstrates a lower deactivation and better catalytic activity for NO reduction than the bimetallic catalyst after hydrothermal aging despite the lower acidic properties as shown by FTIR-Pyr spectroscopy owing to the presence of tungsten oxide crystallites. The “severe” stage of aging occurring in the absence of W led to the formation of copper oxide agglomerates detected using STEM and H2-TPR techniques being responsible for the deterioration of SCR activity of the aged Fe-Cu-ZSM-5.

Fabrication of polyhedral Cu–Zn oxide nanoparticles by dealloying and anodic oxidation of German silver alloy for photoelectrochemical water splitting

A significant effort has been dedicated to the synthesis of Cu–Zn oxide nanoparticles as a robust photocathode material for photoelectrochemical water splitting. Cu–Zn oxide nanoparticles were formed by controlled anodization of German silver (Cu–Zn–Ni) alloy in an aqueous electrolyte. Scanning electron microscopy (SEM) demonstrates the dependence of the obtained nanostructures on the anodization time. The X-ray diffraction (XRD) patterns showed the formation of copper oxide (CuO) and zinc oxide (ZnO) nanoparticles with good stability. This was also confirmed by the compositional X-ray photoelectron spectroscopy (XPS) analysis. The obtained polyhedral nanoparticles showed high optical activity with adequate bandgap energy. These optimized nanoparticles achieved boosted photocurrent of − 0.55 mA/cm2 at − 0.6 V vs. SCE under AM 1.5 illumination, confirming the role of the optimized dealloying and thermal treatment in tuning the photoelectrochemical performance of the material.

Investigating the Efficacy of Hafnium Dioxide Barrier Layers to Halt Copper Oxide Formation in Redistribution Layers for Three-Dimensional (3D) Packaging

HfO2 is investigated for its suitability to act as an oxygen and moisture barrier to prevent Cu oxidation in redistribution layers (RDLs) in 3D packaging technologies. HfO2 barriers of varying thicknesses were deposited via atomic layer deposition (ALD) on Cu surfaces and then stressed by (i) high temperature stress and (ii) humidity and thermal stress for 1000 h to ascertain the optimal thickness to prevent oxidation of the Cu. The thickness of the ALD HfO2 film was monitored by ellipsometry, while the extent of Cu oxidation was monitored by focus ion beam prepared SEM cross sections. It is found that ∼9 nm of HfO2 is sufficient to prevent Cu oxidation.

High-precision and high-efficiency copper removal by femtosecond laser in mixed hydrochloric acid‑oxygen atmosphere

Low-defect, high-efficiency, and high-precision copper (Cu) removal is critical for the development of high-density 3D-integration technology for integrated circuits (ICs). Herein, a hydrochloric acid (HCL)‑oxygen (O2) assisted femtosecond (fs) laser removal process was proposed for Cu removal in ICs. In the process, while fs-laser ablates Cu, the heat generated by fs-laser promotes the reaction between O2 and Cu to form copper oxide, and then HCL dissolves copper oxide. Based on the synergistic corrosion effect of the HCL and O2, Cu removal with high efficiency and high precision is realized by the HCL-O2 assisted fs-laser removal process. Compared with those in air atmosphere, the surface quality and removal efficiency of the Cu film processed by fs-laser in HCL-O2 atmosphere are improved by 41 % and 50 % respectively, indicating the application potential of HCL-O2 assisted fs-laser ablation process in Cu removal for ICs. Furthermore, the strategy of introducing chemical reaction into laser processing provides a way to develop new laser processing technology.

Synthesis of CuO nanoparticles stabilized with gelatin for potential use in food packaging applications

In the present study, a method for the synthesis of gelatin-stabilized copper oxide nanoparticles was developed. Synthesis was carried out by direct chemical precipitation. Copper sulfate, chloride, and acetate were used as precursors for the copper oxide synthesis. Gelatin was used as a stabilizer. It was found that the formation of monophase copper oxide II only occurred when copper acetate was used as a precursor. Our results showed that particles of the smallest diameter are formed in an aqueous medium (18 ± 6 nm), and those of th largest diameter—in an isobutanol medium (370 ± 131 nm). According to the photon correlation spectroscopy data, copper oxide nanoparticles synthesized in an aqueous medium were highly stable and had a monomodal size distribution with an average hydrodynamic radius of 61 nm. The study of the pH effect on the colloidal stability of copper oxide nanoparticles showed that the sample was stable in the pH range of 6.8 to 11.98. A possible mechanism for the pH influence on the stability of copper oxide nanoparticles is described. The effect of the ionic strength of the solution on the stability of the CuO nanoparticles sol was also studied, and the results showed that Ca2+ ions had the greatest effect on the sample stability. IR spectroscopy showed that the interaction of CuO nanoparticles with gelatin occurred through the hydroxyl group. It was found that CuO nanoparticles stabilized with gelatin have a fungicidal activity at concentration equivalent 2.5 · 10−3 mol/L and as a material for food nanopackaging can provide an increase in the shelf life of products on the example of strawberries and tomatoes. We investigated the possibility of using methylcellulose films modified with CuO nanoparticles for packaging and storage of hard cheese “Holland”. The distribution of CuO nanoparticles in the methylcellulose film was uniform. We found that methylcellulose films modified with CuO nanoparticles inhibited the growth and development of QMAFAM, coliforms, yeast and mold in experimental cheese sa mples. Our research has shown that during the cheese storage in thermostat at 35 ± 1 °C for 7 days, CuO nanoparticles migrated to the product from the film. Nevertheless, it is worth noting that the maximum change in the concentration of copper in the experimental samples was only 0.12 µg/mg, which is not a toxic concentration. In general, the small value of migration of CuO nanoparticles confirms the high stability of the developed preparation. Our results indicated that the CuO nanoparticles stabilized with gelatin have a high potential for use in food packaging – both as an independent nanofilm and as part of other packaging materials.

CoCu-hydroxyquinoline loaded on copper foam as effective pre-catalytic electrode for oxygen evolution

• An effective pre-catalytic electrode composed of CoCu hydroxyquinoline salts was prepared. • The pre-catalytic electrode will be activated during the electrochemical process. • The in situ formed CuO/COOOH would act as the catalytic active phase. • The optimized electrode can afford 20 mA cm −2 with overpotential of 282 mV in 1 M KOH. • The optimized electrode shows excellent stability. Cobalt-copper bimetal hydroxyquinoline salts grown on copper foam substrate are successfully synthesized. The copper foam supported cobalt-copper bimetal hydroxyquinoline salts can act as pre-catalysts for oxygen evolution. The as-obtained electrode presents prominent catalytic performance and stability, showing an overpotential of 282 mV for 20 mA cm −2 in 1 M KOH. Furthermore, the optimized catalytic electrode can maintain the current density of 96.7% after 36 h of catalysis operation at 80 mA cm −2 . The prominent catalytic performance can be attributed to the in situ generated catalytic active species derived from the hydroxyquinoline salt pre-catalysts. Characterizations of the used catalyst after catalysis confirm the formation of cobalt oxyhydroxide and copper oxide, acting as the actual active species for the catalytic process. This convenient but low-cost fabrication method and the favorable catalytic activity make this optimized catalytic electrode a hopeful candidate for electrochemical water splitting.

Hydrothermally formed copper oxide (CuO) thin films for resistive switching memory devices

This work presents the preliminary research on Metal-Insulator-Metal (MIM) structures containing copper oxide (CuO) layers for memory applications. Structural and optical investigations of fabricated materials have shown distinct differences in chemical compositions of ‘as grown’ and thermally annealed CuO, i.e., ‘HT + RTP’ film. Those differences strongly influence the electrical behavior of fabricated MIM structures. The examined electrical performance of fabricated devices revealed stability and repeatability of the HRS/LRS ratio over time. The presented results have demonstrated the possible application of CuO thin films in low-power and high-speed Resistive Random-Access Memory (RRAM) devices.

Effect of time, temperature and composition on the performance of conductive adhesives made of silver-coated copper powder

The effects of temperature and time (200, 250 and 300 °C for 15 h in total) on the electrical resistivity and phases of conductive adhesives were studied. Also, the effect of filler content (70 to 85 wt%) and graphite addition (2 to 15 wt%) on the performance of conductive adhesives in terms of electrical resistivity were investigated. These adhesives were prepared from Cu@Ag particles containing 20 and 50 wt% of silver. Two-point conductivity measurements, SEM, XRD, and TG/DSC analyses were used to evaluate the properties of the adhesives. The results showed that at a constant filler content, the electrical resistivity of adhesives prepared from powder containing 20 wt% silver increases with exposure time. However, the majority of the adhesives prepared from powder containing 50 wt% of silver under similar oxidation conditions had almost constant electrical resistivity. Moreover, the results of temperature change on the electrical resistivity showed that the electrical resistivity of adhesives prepared from powder containing 20 wt% of silver increases with temperature, although this increase was noticeable in some samples and negligible in the others. In contrast, an increase in temperature had very little effect on the electrical resistivity of most adhesives made from powders containing 50 wt% silver. The study of the effect of silver content in particles showed that adhesives prepared with filler containing 50 wt% of silver had significantly less electrical resistivity than adhesives prepared with filler containing 20 wt% of silver at all three temperatures. According to the XRD results, the formation of copper (II) oxide and its detrimental effect on electrical conductivity was the main reason of electrical conductivity reduction of adhesives. Graphite addition to an adhesive formula showed that the presence of graphite in appropriate amounts can prevent the oxidation of copper. Adhesives containing graphite after exposure at three temperatures in total for 15 h had electrical resistivities less than 0.028 Ω cm, while graphite-free adhesives under the same conditions had electrical resistivities of less than 0.072 Ω cm.

An internal-oxidation-based strategy induced high-density alumina in-situ nanoprecipitation and carbon nanotube interface optimization for co-reinforcing copper matrix composites

Achieving high strength and ductility for copper matrix composites reinforced by carbon nanofillers remains challenging due to secondary agglomeration, few intragranular distributions, and poor interfacial bonding in carbon/copper system. Here, we report an internal-oxidation-based fabrication strategy to simultaneously facilitate high-density in-situ nanoprecipitation into matrix grain interior as well as interfacial optimization between carbon nanotubes (CNTs) and copper matrix. Comprehensive experimental results show that in-situ generation of high-density coherent γ-Al2O3 nanoparticles with intragranular distribution and formation of amorphous copper oxides (CuxOy) between CNTs and Cu are attributed to oxygen diffusion and in-situ solid-reaction ascribing to thermodynamic driving force during internal oxidation. The co-strengthening effect of high-density γ-Al2O3 nanoparticles and interface optimized CNTs is corroborated to contribute to the high mechanical properties of the composite, which exhibits a high tensile strength of up to 510 MPa and excellent ductility of 20.2%. Mechanism analysis indicates that both high-density intragranular γ-Al2O3 nanoparticles and interface optimized CNTs co-render high strength of the hybrid composite with regard to Orowan strengthening and highly effective load transfer strengthening respectively, which greatly agrees with theoretical quantitative and experimental values of corresponding strength contributions. Meanwhile, cooperation of the dislocation accumulation caused by intragranular γ-Al2O3 nanoparticles and cracking resistance enhanced by interfacial bonding optimized CNTs collectively maintains tensile ductility. The present design concept may provide a promising strategy for achieving the remarkable co-strengthening effect of nanoscale dual-reinforcements, contributing to high strength and ductility in other carbon nanofillers reinforced metal matrix composites.

SYNTHESIS AND CHARACTERIZATION OF COPPER OXIDE NANOPARTICLES USING DIFFERENT PRECURSOR

Nano copper oxide (CuO) was synthesized using different precursors of copper salts such as copper acetate [Cu(CH3COO)2.2H2O] and copper chloride(CuCl2..2H2O) with the same experimental condition. The nanoparticles were characterized by UV-Vis, FT-IR, XRD, EDX, TEM, SAED, DLS and DSC. The results indicated that the grains of copper oxide were aggregated to formed particle sizes of about 50-100nm, 14.14-17.54nm and 283-449nm from TEM, XRD and DLS, respectively. The DLS analysis of CuONPs was also carried out in the temperature interval from room temperature to 4000C. In the study, the particle size has different sizes, but all the characterization results showed the formation of copper oxide as CuO, which was in agreement with the previously synthesized and reported CuONPs. The method used in the study can be useful for synthesizing other nanoparticles with the desired nanostructure

Formation of copper oxide II in polymer solution-blow-spun fibers and the successful non-woven ceramic production

Copper oxide II is a p-type semiconductor that can be used in several applications. Focusing on producing such material using an easy and low-cost technique, we followed an acetate one-pot-like route for producing a polymer precursor solution with different acetates:PVP (polyvinylpyrrolidone) weight ratios. Then, composite nanofibers were produced using the solution blow spinning (SBS) technique. The ceramic CuO samples were obtained after a calcination process at 600 °C for 2 h, applying a heating rate of 0.5 °C/min. Non-woven fabric-like ceramic samples with average diameters lower than 300 nm were successfully obtained. SEM images show relatively smooth fibers with a granular morphology. XRD shows the formation of randomly oriented grains of CuO. In addition, FTIR and XRD analyses show the CuO formation before the heat treatment. Thus, a chemical reaction sequence was proposed to explain the results.

Boron Modified Bifunctional Cu/SiO2 Catalysts with Enhanced Metal Dispersion and Surface Acid Sites for Selective Hydrogenation of Dimethyl Oxalate to Ethylene Glycol and Ethanol.

Boron (B) promoter modified Cu/SiO2 bifunctional catalysts were synthesized by sol-gel method and used to produce ethylene glycol (EG) and ethanol (EtOH) through efficient hydrogenation of dimethyl oxalate (DMO). Experimental results showed that boron promoter could significantly improve the catalytic performance by improving the structural characteristics of the Cu/SiO2 catalysts. The optimized 2B-Cu/SiO2 catalyst exhibited excellent low temperature catalytic activity and long-term stability, maintaining the average EG selectivity (Sel.EG) of 95% at 190 °C, and maintaining the average EtOH selectivity (Sel.EtOH) of 88% at 260 °C, with no decrease even after reaction of 150 h, respectively. Characterization results revealed that doping with boron promoter could significantly increase the copper dispersion, enhance the metal-support interaction, maintain suitable Cu+/(Cu+ + Cu0) ratio, and diminish metallic copper particles during the hydrogenation of DMO. Thus, this work introduced a bifunctional boron promoter, which could not only improve the copper dispersion, reduce the formation of bulk copper oxide, but also properly enhance the acidity of the sample surface, so that the Cu/SiO2 sample could exhibit superior EG selectivity at low temperature, as well as improving the EtOH selectivity at high temperature.

TiO2 film on copper: Effects of the temperature and the intermediate layer of nickel on adhesion and photocatalytic activity

AbstractThe deposition of titanium dioxide (TiO2) on copper (Cu) substrate was performed by electrophoresis in an aqueous medium. The samples obtained were then calcined at temperatures ranging from 300°C to 550°C with a pitch of 50°C. After calcinations at 500°C and 550°C, the TiO2 film blackened and detached from the substrate. The XRD analyzes confirmed the formation of copper oxide at 350°C. The photocatalytic test carried out with amido black 10B (AB) under ultraviolet (UV) radiations showed that the percentage of discoloration decreases by increasing the calcination temperature. Moreover, the results obtained by the scratch test demonstrated that the samples exhibited poor adhesion. In order to improve the film adhesion and to avoid the formation of copper oxide, we introduced a nickel (Ni) layer. Afterward, the TiO2/Ni/Cu sample was calcined at 550°C, which allowed eliminating the forms of copper oxide, on the one hand, and improving the adhesion of the film, on the other hand. The rate of AB discoloration with TiO2/Ni/Cu sample was 25.54%, which is close to that of TiO2/Cu calcined at 450°C.