Formation Of Metal Oxides Research Articles

(Invited) CrOx-Mediated Stability and Performance Enhancement of Ni/NiO-Mg:SrTiO3 in Photocatalytic Water Splitting

In the field of photocatalytic water splitting to produce sustainable hydrogen, significant breakthrough in Apparent Quantum Efficiency (AQE) has been obtained by modification of SrTiO3-based semiconductors. Combining doping with aliovalent Al(III) and functionalization with CrOx-promoted Rh nanoparticles, AQEs of close to 100% have been reported upon UV excitation. In this study it is demonstrated that economically more viable Ni-based nanoparticles allow Mg-doped SrTiO3-based semiconductors to provide for AQEs >25%. A key and novel finding is that photodeposited CrOx not only promotes the performance of the Ni particles (AQY increases from ~10% to 26%), but also enhances the stability, allowing sustained cyclic operation (day-night cycles). In situ elemental analysis shows that CrOx significantly reduces dissolution of Ni from Ni/NiO-Mg:SrTiO3 by formation of a Ni-Cr mixed metal oxide. This is confirmed by state-of-the-art electron microscopy, which furthermore demonstrates that upon preparation, CrOx is photodeposited in the vicinity of several, but not all, Ni/NiO particles. Inhomogeneities in the interfacial contact between the Ni/NiO particles and the Mg:SrTiO3 substrate likely affect the probability of reduction of Cr(VI)-species during photodeposition, explaining the inhomogeneity. In addition it is revealed that the dopant Mg is essential in providing favorable interfacial contact with several NiO/Ni particles and effective promotion of these particles by CrOx. In general this presentation provides synthesis protocols that allow for intensification of interfacial contacts of Ni/NiO and (doped) SrTiO3, and stability enhancement by photodeposition of CrOx.

Amine‐functionalized metal–organic frameworks/epoxy nanocomposites: Structure‐properties relationships

AbstractAmine‐functionalized MIL‐101(Cr)‐NH2 metal–organic frameworks (MOF‐N)/epoxy nanocomposites with Excellent cure label and high thermal stability were developed. Structure–property relationship was discussed by comparison of the cure state, thermal and viscoelastic behavior of epoxy nanocomposites containing pristine MOF or MOF‐N applying differential scanning calorimetry (DSC), thermogravimetric analysis, and dynamic mechanical analysis. Epoxy containing 0.3 wt% MOF‐N exhibited high glass transition temperature (Tg) of 96°C compared with 85°C observed for epoxy/MOF system. Thus, MOF‐N played the role of catalyst in epoxy/amine curing reaction. Correspondingly, a lower activation energy was obtained based on cure kinetics modeling based on DSC measurements. Besides, incorporation of low amount (0.5 wt%) MOF‐N induced an early‐state resistance against decomposition, featured by 11°C rise in decomposition temperature at 5% weight loss. This was ascribed to the formation of porous metallic oxides during thermal decomposition of MOF‐N in the epoxy system acting as a heat barrier, which increased the activation energy of decomposition. Amine‐functionalization considerably prevented from further oxidation of the inner part of the matrix.

Efficient catalytic application of Cu-Fe bimetallic nanoparticles towards the preparation of bio-medically important polymer based Schiff bases

A Cu and Fe based bimetallic nanoparticle (BMNP) was prepared by chemical reduction method through the formation of CuO and Fe2O3 nanocomposites. The Cu-Fe BMNP was characterized by FT-IR, UV–visible, fluorescence emission spectra, XRD, XPS, HR-TEM, SEM, EDX and VSM like instruments. The FT-IR spectrum showed a metal-oxide stretching peak around 600 cm-1 associating with the Fe-O and Cu-O composites. The formation of metal oxides was confirmed by XRD. The Janus nanoparticle formation between Fe and Cu was confirmed by HR-TEM. The surface catalytic activity of Cu-Fe BMNP was tested towards the Schiff base (SB) formation between alcohol and amine in an air atmosphere. The amount of SB formation was determined by using the 1H NMR spectrum. Among the systems, the PVA based SB yielded 20% via ketone formation.

Influence of sodium aluminate concentration and process duration on microstructure, mechanical and electrochemical behavior of PEO coatings formed on CP-Ti

Abstract Mixed titanium-aluminum oxide coatings were successfully grown on grade-2 commercially pure titanium substrates by using plasma electrolytic oxidation technique. The mechanical features and the resistance against corrosion were attributed to microstructural, morphological and surface changes resulting from different preparation conditions. The formation of bulk metal oxides consisting of a dominant TiAl2O5/Ti2Al6O13 structure together with α-Al2O3 and γ-Al2O3 phases in the coatings accompanied by fully oxidized metal atoms on top of the surface showed a maximum 24.5 GPa hardness and 45 N adhesive critical load, respectively. Best corrosion performance of the coatings in 3.5% NaCl was found to be two orders of magnitude higher when compared to uncoated Ti.

Selective Oxidation of Methane to Methanol over Ceria‐Zirconia Supported Mono and Bimetallic Transition Metal Oxide Catalysts

AbstractSeveral ceria‐zirconia supported mono and bi‐metallic transition metal oxide clusters containing Fe, Cu, and Ni are synthesized by dry impregnation. Through XRD, H2‐TPR, NH3‐TPD, pyridine adsorption followed by FTIR spectroscopy and XAS, the well‐dispersed nature of the transition metal oxide clusters is revealed, and the Lewis acidity of the catalysts is assessed. In‐situ FTIR spectroscopy is used to monitor the methane activation on catalyst surfaces. All catalysts activate methane at 250 °C forming methyl, alkyl, and methoxy species on the catalyst surface. By co‐feeding steam and oxygen together with methane, continuous direct oxidation of methane to methanol can be achieved, with the complete oxidation to CO2 as the other reaction path. Methoxy species are found to be a key intermediate for methanol production. Lowering the methane conversion improves the methanol selectivity. By extrapolation, it is estimated that methanol selectivity close to unity can be achieved below a threshold of methane conversion at about 0.002 %. The formation of CuO and NiO mixed metal oxides produces stronger Lewis acid sites and yields higher methanol selectivity.

Effect of Powder Particle Concentration and Tool Electrode Material amid Zinc Powder-Mixed µEDM of Biocompatible Mg Alloy AZ91D

Magnesium (Mg) alloys exhibit high strength and biocompatibility, coupled with a unique characteristic that is the ability to degrade over time. These characteristics of Mg alloys led to the development of several biodegradable medical implants such as screw, pin, and plate. Powder-mixed micro-electric discharge machining (PM-μEDM) was found to substantially improve the surface and metallurgical properties of biodegradable alloys and therefore, it was used in this study to investigate the machinability of Mg alloy AZ91D. PM-μEDM was performed at varying zinc (Zn) powder particle concentrations (0 to 8 g/l) using copper and brass tool electrodes. The effect of these input control variables on the machining time, dimensional deviation, and characteristics of the machined surface was experimentally examined. The machined surfaces were primarily analyzed by field-emission scanning electron microscope, energy-dispersive spectrometry, and x-ray diffraction (XRD). The findings showed a significant reduction in the machining time and dimensional deviation during PM-μEDM at 4 g/l powder particle concentration using the copper tool electrode. Moreover, the presence of resolidified debris, powder particles, and formed metal oxides and carbides in the recast layer, produced with the aid of the copper tool electrode at 4 g/l powder particle concentration, exhibited a considerable surface modification.

Promoting hydrocarbon production from fatty acid pyrolysis using transition metal or phosphorus modified Al-MCM-41 catalyst

Oleaginous biomass conversion to liquid hydrocarbon biofuels has emerged as an effective solution to the energy crisis and environmental problems. In this process, the removal of oxygenated compounds will directly affect the effectiveness of subsequent biofuel applications. Herein, deoxygenation of oleic acid by catalytic cracking was conducted using five various elements (La, Ni, P, Zr and Ce) modified Al-MCM-41. The related characterizations were carried out for these catalysts, including N2 physisorption, XRD, XPS, pyridine-FTIR and NH3-TPD techniques. The results showed the mesoporous structure of Al-MCM-41 was maintained after different modifications, and these catalysts greatly improved the hydrocarbons content and physiochemical properties of biofuels. The modified catalysts tended to facilitate the decarbonylation pathway and showed high selectivity to alkane and aromatic hydrocarbons. Besides, La/Al-MCM-41 presented excellent anti-coking activity. Ni/Al-MCM-41 showed both high dehydrogenation and deoxygenation activities. The Zr modification and Ce modification had a promotion effect in the deoxidizing activity of the catalyst, owing to the formation of oxophilic metal oxides. Noteworthily, P/Al-MCM-41 displayed the best deoxidizing performance due to its high Brönsted acidity, which caused the highest hydrocarbons content (82.30 %) and the lowest fatty acids content (around 0 %) of the biofuel. Moreover, the resulting biofuel had not only low oxygen content (3.88 wt.%) and acid value (5.47 mgKOH g−1) but also a high calorific value (44.50 MJ kg−1), which could be processed into green diesel. Hence, the catalytic cracking of fatty acid over P/Al-MCM-41 has excellent potential to produce high-quality renewable fuels.

Synthesis of Nano Ag-La-Co Composite Metal Oxide for Degradation of RB 5 Dye Using Catalytic Ozonation Process

ABSTRACT Nanoscale composite metal oxide of Ag-La-Co was prepared by co-precipitation method for the treatment of Reactive Black 5 using catalytic ozonation process. Further, the catalyst was characterized by transmission electron microscope, X-ray powder diffraction (XRD), scanning electron microscope - energy dispersive X-ray (SEM-EDX) and Brunauer–Emmett–Teller (BET) surface area analyzer for clarity of the phenomenon. The factors such as amount of catalyst (0.2–1.2 g/L), solution pH (2, 7, and 12), initial dye concentration (100–1,000 mg/L), and ozone flow rate (30–60 LPH) were found to influence the process. The characterization results confirm the formation of the composite metal oxide of Ag-La-Co. The degradation efficiency of catalytic ozonation was 63% compared to 32% and 4% in ozonation without catalyst and adsorption on the catalyst, respectively. Furthermore, it was observed that a pseudo-first-order kinetics model fits well with the experimental data. In addition, the effect of tert-butyl alcohol, a hydroxyl radical scavenger, has been studied. Lastly, the repetitive use of the synthesized catalyst showed that even after three consecutive runs, the catalytic activity is not much degraded, and therefore, the degradation efficiency of the synthesized catalyst was comparatively high; about 95% of Total Organic Carbon (TOC) removal was achieved at solution pH 7, amount of catalyst 1 g/L, reaction time 80 min, and ozone flow rate 30 LPH, indicating an economically viable option for industrial wastewater treatment.

Syntheses and identification of cefotaxime-non-transition metal complexes

The coordination chemistry of the biologically active cefotaxime sodium and, in particular, the mode of its interaction with some metal ions of electronic configuration d0 (alkaline earth) and others, Zn(II), Pb(II), and Ce ions with the electronic configuration d10 has been investigated. Seven complexes were synthesized, isolated in the solid-state, and characterized by elemental analyses, conductivity measurements, IR and UV/VIS spectra, as well as thermal analyses. Based on the obtained experimental data and literature, the structural formulae to these complexes were suggested and formulated as [Mg(cef)2].2H2O (1), [Ca(cef)2].2H2O (2) [Sr(cef)2].2H2O (3), [Ba(cef)2].2H2O (4), [Zn(cef)2(H2O)2] (5), [Pb(cef)2(H2O)2].4H2O (6) and [Ce(cef)2(H2O)2].3H2O (7). The data obtained show that cefotaxime interacted with metal in a molar ratio of 2:1, respectively. Cefotaxime bonded to metal ions in the anionic form as a bidentate ligand through the lactam carbonyl (C=O) and the carboxylate group (COO-). Tetrahedral and octahedral shapes were proposed as the most likely geometries associated with a metal having such electronic configurations. The absorption bands observed in the electronic spectrum of free cefotaxime are also observed with some shifts in the spectra of its complexes, indicating their formation. The absorption bands of free cefotaxime and its complexes were assigned to electronic transitions. The thermal analyses date strongly support the structures proposed for the complexes and indicate the formation of the corresponding metal oxide as a final decomposition product.

Sputtering of Mo and Ag with xenon ions from a radio-frequency ion thruster.

The goal of this work is to set up an electric propulsion (EP) sputtering test section as a feasibility study for ground-based sputter testing of spacecraft materials with a radio-frequency ion thruster. Such experiments deliver valuable data, which are scarce but highly desired to model EP-based space missions, for example, with the Spacecraft Plasma Interaction System in order to predict the performance and lifetime of spacecraft components. This study assessed if sufficient testing conditions can be met to produce reliable experimental material data in the future. Therefore, the thruster was operated at ion energies of 1.5 and 1.8 keV, and a quartz crystal microbalance (QCM) was installed to detect sputter deposition rates. Molybdenum (Mo) and silver (Ag) were chosen as sputter targets. Wafer substrates served as a passive sampling method to characterize the composition of sputtered material by Rutherford backscattering spectrometry. Additionally, sputtering simulations matching the experimental conditions were performed with the software SDTrimSP. We obtained comparable experimental and computational data, as measured sputter deposition rates lie within the simulated order of magnitude and to some extent show the predicted angular dependence. Analysis of the deposited sputter material revealed the formation of metal oxides, which requires a future adaption of the material specific QCM settings. Furthermore, the cooling system of the QCM sensor head was not sufficient, limiting the comparability of results.

Growth of porous anodic TiO2 in silver nitrate solution without fluoride: Evidence against the field-assisted dissolution reactions of fluoride ions

Al, Ti, Zr and other metals can be anodized to form metal oxides with a porous structure or a nanotube structure. However, the mechanism of formation of oxide nanopores is still controversial. Anodic TiO2 nanotubes are usually obtained in an electrolyte containing fluoride ions, so a field-assisted dissolution reaction involving fluoride ions is considered to be the main reason for the formation of nanopores. In this paper, titanium was anodized at high current in a silver nitrate solution without fluoride, and a porous titanium oxide structure was obtained, which proves that a field-assisted dissolution reaction involving fluoride ions is not essential for the formation of nanopores. The electronic current leads to oxygen evolution, and the oxygen bubble mold effect is the real reason for the formation of nanopores. These interesting results show that the mechanism of formation of anodized TiO2 nanotubes is the same as that of porous oxide structures. Moreover, the growth rate of nanotubes in an aqueous solution of silver nitrate was much higher than that in a glycol solution of ammonium fluoride at the same voltage.

Development of Fe-5Al-1C alloys for grinding ball

Our object of research is to combine the properties of Mn and the advantages of Fe-Al-C to improve the performance of grinding ball materials. Three Fe-5Al-1C alloys with compositions of 15 wt% Mn (FAM15), 20 wt% Mn (FAM20), and 25 wt% Mn (FAM25) were investigated. Argon gas was used to assist the removal of dissolved oxygen and to control the formation of metal oxides during Fe-Al-Mn-C (FAMC) fabrication. Microstructure analysis was conducted using scanning electron microscopy, and the Vickers microhardness tester was used to evaluate hardness. To guarantee the Fe-5Al-1C-Mn alloy phase, X-ray diffraction (XRD) test was performed. The EDS test was carried out to show the composition at different points and to observe the presence of several phases in the FAMC alloy system. A pin-on-disc method was employed for a dry sliding wear test, and corrosion testing was performed using the three-electrode cell polarization method. With the addition of Mn, the Vickers hardness of the FAMC alloy raised from 194.4 VHN at 15 wt% to 265 VHN at 25 wt%. The tensile strength and fracture elongation values were 424.69 MPa, 27.16 % EI; 434.72 MPa, 33.6 % EI; and 485.71 MPa, 38.48 % EI for FAM15, FAM20, and FAM25, respectively. A crucial factor for increasing the performance of grinding ball is the wear mechanism. The wear rate results for FAM25 show a decline of more than 57 % compared to FAM15 due to an increase in the hard intermetallic area. The addition of Mn elements increased the corrosion resistance of the FAMC alloys; the lowest corrosion rate occurred at 25 wt% Mn content at up to 0.036 mm/yr. According to the experimental results, the FAM25 alloys have the highest mechanical and corrosion resistance of the three types of alloys. The FAMC alloy is a promising candidate for application as a material for grinding balls by optimizing the Mn content

Efficient overall water splitting in acid with anisotropic metal nanosheets

Water is the only available fossil-free source of hydrogen. Splitting water electrochemically is among the most used techniques, however, it accounts for only 4% of global hydrogen production. One of the reasons is the high cost and low performance of catalysts promoting the oxygen evolution reaction (OER). Here, we report a highly efficient catalyst in acid, that is, solid-solution Ru‒Ir nanosized-coral (RuIr-NC) consisting of 3 nm-thick sheets with only 6 at.% Ir. Among OER catalysts, RuIr-NC shows the highest intrinsic activity and stability. A home-made overall water splitting cell using RuIr-NC as both electrodes can reach 10 mA cm−2geo at 1.485 V for 120 h without noticeable degradation, which outperforms known cells. Operando spectroscopy and atomic-resolution electron microscopy indicate that the high-performance results from the ability of the preferentially exposed {0001} facets to resist the formation of dissolvable metal oxides and to transform ephemeral Ru into a long-lived catalyst.

Effect of oxidation on the thermal expansion of a refractory multicomponent alloy

ABSTRACT We employ first-principles calculations to examine the role of oxidation on the thermal expansion behaviour of a refractory multicomponent alloy. Our results reveal that the linear expansion and the coefficient of volumetric expansion over a range of temperatures have higher values for the oxidised alloy than the pure material. The enhanced expansion for the oxidised alloy is attributed to significant changes in the lattice parameter of the alloy upon surface oxidation. During oxidation, the diffusion of oxygen atoms to the subsurface layer of the alloy after complete surface coverage produces a displacement of the constituent elements that form metal oxides. This depletion creates vacancy sites in the lattice for enabling enhanced expansivity in the oxidised structure relative to the pure refractory alloy.

Electron Transfer through a Natural Oxide Layer on Real Metal Surfaces Occurring during Sliding with Polytetrafluoroethylene: Dependence on Heat of Formation of Metal Oxides

Electron emission (EE) from real metal surfaces occurring during sliding contact with a polytetrafluoroethylene (PTFE) rider has been investigated using the thermodynamic data of metal oxides and the X-ray photoelectron spectroscopy (XPS) intensity ratio of oxygen/metal on the surfaces. EE was termed triboelectron emission (TriboEE). Rolled metal sheets of 18 types were used. The metal‒oxygen bond energy calculated from the heat of the formation of metal oxide, (D(M–O)), was shown to be a key factor in dividing the EE into two routes, the so-called Schottky effect and the tunnel effect, due to the surface oxide layer. The metals in periodic groups 4 (Ti and Zr), 5 (V, Nb, and Ta), and 6 (Mo and W) maintained higher values of D(M–O), while, moving down the groups, the TriboEE intensity increased, being ascribed to the former route. In groups 10 (Ni, Pd, and Pt) and 11 (Cu, Ag, and Au), the D(M–O) values decreased moving down the groups, but the TriboEE intensity increased significantly, which can be attributed to the latter route. Furthermore, with the increase in the electrical conductivity of metals, the TriboEE intensity became remarkably high, while the D(M–O) value fell rapidly and became almost constant. The XPS results showed that the dependence of the D(M–O) and XPS metal core intensity on the O1s intensity and the XPS intensity ratio of the O1s/metal core was different between groups 10 and 11 and groups 4, 5, and 6. It was concluded that, under the electric field caused on the real metal surface by the friction with PTFE, the electron from metals with small D(M–O) values predominantly tunnels the surface oxide layer as a surface barrier, while with large D(M–O) values, the electron passes over the top of the barrier.

Oxide Formation during Transpassive Material Removal of Martensitic 42CrMo4 Steel by Electrochemical Machining.

The efficiency of material removal by electrochemical machining (ECM) and rim zone modifications is highly dependent on material composition, the chemical surface condition at the break through potential, the electrolyte, the machining parameters and the resulting current densities and local current density distribution at the surfaces. The ECM process is mechanistically determined by transpassive anodic metal dissolution and layer formation at high voltages and specific electrolytic compositions. The mechanisms of transpassive anodic metal dissolution and oxide formation are not fully understood yet for steels such as 42CrMo4. Therefore, martensitic 42CrMo4 was subjected to ECM in sodium nitrate solution with two different current densities and compared to the native oxide of ground 42CrMo4. The material removal rate as well as anodic dissolution and transpassive oxide formation were investigated by mass spectroscopic analysis (ICP-MS) and (angle-resolved) X-ray photoelectron spectroscopy ((AR)XPS) after ECM. The results revealed the formation of a Fe3−xO4 mixed oxide and a change of the oxidation state for iron, chromium and molybdenum, e.g., 25% Fe (II) was present in the oxide at 20.6 A/cm2 and was substituted by Fe (III) at 34.0 A/cm2 to an amount of 10% Fe (II). Furthermore, ECM processing of 42CrMo4 in sodium nitrate solution was strongly determined by a stationary process with two parallel running steps: 1. Transpassive Fe3−xO4 mixed oxide formation/repassivation; as well as 2. dissolution of the transpassive oxide at the metal surface.

Hierarchically connected electrospun WO3 nanowires – An acetaldehyde sensor

Hierarchically connected low-dimensional metal oxide nanostructures have been preferred to fabricate gas-sensing elements owing to their enhanced sensing response. In this juncture, hierarchical architectures of WO3 nanowires were synthesized using electrospinning technique with polyvinyl alcohol and ammonium metatungstate hydrate as precursor. X-ray diffraction analysis revealed the polymer evaporation and metal oxide formation with phase transformation of WO3 nanowires from monoclinic to orthorhombic and back to monoclinic as an effect of calcination temperatures (673–973 K). The variation in the interconnected grain features of WO3 nanowires as a function of calcination temperature was observed using field emission scanning electron microscope and transmission electron microscope. The formation of higher oxidation states of tungsten (W6+) and increased oxygen vacancies were observed for the samples calcined at higher temperatures through X-ray photoelectron spectrometer. Electrical studies for 873 K sample showed the maximum mobility of electrons due to the highly interconnected nanowires with minimum grain boundary resistance. The gas sensing responses of WO3 nanostructures were investigated and WO3 sample calcined at 873 K with maximum mobility showed a selective response of 5537 towards 75 ppm of acetaldehyde at room temperature.

Synthesis, characterization and DFT investigation of new metal complexes of Ni(II), Mn(II) and VO(IV) containing N,O-donor Schiff base ligand

In this work, a bidentate Schiff base ligand (HL) containing N and O as donor heteroatoms has been used to synthesize series of new stable metal complexes of general composition of M(L)2 with M = Mn, Ni and VO. This ligand was obtained from condensation of 2-methoxybenzylamine on 2,3-dihydroxybenzaldehyde in methanolic solutions in which its complexes were obtained by mixing the corresponding metal acetate salt and the ligand in 1:2 molar ratio. The resulting three complexes have been characterized by different analytical techniques like FT-IR, UV-Vis, mass spectroscopy, thermogravimetry and cyclic voltammetry, to identify their molecular structures and redox/electrochemical properties. Moreover, the effect of the metal on the complexes electronic properties with their reactivity has also been studied by Density Functional Theory (DFT). The stable structures were optimized by using the hybrid B3LYP/6–31 G method. The spectroscopic data obtained suggest that the metal is bonded to the ligand through the phenolic-like oxygen and the imine-type nitrogen atoms. Electronic and vibrational absorption spectra of the nickel complex was found to be of square-planar geometry while square-pyramidal and octahedral geometries have been proposed for VO(IV) and Mn(II) complexes, respectively. The thermogravimetric analyses of these complexes confirmed the presence of water molecules in their structures and thermal decomposition led to the formation of metal oxides as the latest residues. The voltammogram of the Ni(II) complex suggests the existence of quasi-reversible redox system in DMSO solution.

Structural and thermal analysis of some imipramine complexes

imipramine interacts with transition metals to give different molar ratios (M:L), (1:1) with Mn(II), Zn(II), Cd(II) and Hg(II) and (1:2) with Cr(III), Fe(III), Co(II), Ni(II) and Cu(II) .All were characterized by elemental analysis, IR, electronic spectra and magnetic susceptibility. IR spectra indicated that imipramine behaves as a bidentate ligand through its heterocyclic nitrogen atom and the tertiary nitrogen atom of the side chain. The geometry around the metal atoms is octahedral in all complexes except for Zn has tetrahedral structure. It was indicated by TGA and DTA analysis that the thermal decomposition of most complexes ended with the formation of metal oxides and carbon residue as a final product. For this reaction, the kinetic parameters and the orders were estimated. The decomposition course and steps were also analyzed. Consequently, decomposition mechanisms were suggested.

Locust Bean Gum as Corrosion Inhibitors in NaCl Solution

In this research, the inhibitive performance of locust bean gum (LBG) on the corrosion behavior of AISI 304 stainless steel (AISI 304SS), E150 Al alloy and copper in 0.15 M NaCl containing various amounts (10–3, 10–2, 10–1, 1, 1.5 and 2 g L–1) of LBG were researched using potentiodynamic polarisation, electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM), energy dispersive X‑ray analysis (EDS) and inductively coupled plasma optical emmision spectrometry (ICP-OES) methods. Polarisation curves indicated that LBG was acting as mixed type inhibitor. All electrochemical measurements showed that inhibition efficiencies increased with increasing LBG concentration. It was determined that the increase of inhibitor efficiency by concentration resulted from the adsorption of LBG to metal surface, and the adsorption fitted to the Langmuir adsorption isotherm equation. The variation in inhibitive efficiency mainly depends on sugar units present in the LBG molecule. The best inhibition shows in 0.15 M NaCl + 2 g L–1 LBG solution. LBG reduced corrosion by slowing the rate of reactions formation without changing anodic and cathodic reactions. In addition, LBG adsorptioned on active sites caused the reduction of corrosion due to geometric block effect. SEM results show that metal surfaces are highly damaged in an inhibitor-free environment. The SEM images with inhibitor environment show that the surface is more homogeneous and smooth. The results of EDS show that the presence of oxygen in the inhibitor medium results in the formation of surface metal oxides, and therefore the reduction of corrosion.