Heterostructure Nanocomposites Research Articles

Energy-levels well-matched direct Z-scheme ZnNiNdO/CdS heterojunction for elimination of diverse pollutants from wastewater and microbial disinfection.

Energy-levels well-matched direct Z-scheme ZnNiNdO/CdS heterojunction was successfully fabricated using facile co-precipitation and ultra-sonication techniques and characterized with XRD, FTIR, Raman, PL, UV-vis, and FE-SEM. The XRD diffractograms confirmed the co-doping of Ni-Nd in ZnO and the formation of heterostructured nanocomposite. FTIR and Raman data showed the presence of metal-oxygen vibration and optical phonon modes of ZnO and CdS. FE-SEM images exhibited the network type morphology. The energy bandgap was redshifted by co-doping (3.37-2.9eV) and was further reduced (2.6eV) by making a composite with CdS. The ZnNiNdO/CdS catalyst degraded 99.7, 49, 96.6, 98.6, and 98.6% methylene blue (MB), p-nitroaniline (P-Nitro), methyl orange (MO), methyl red (MR), and rhodamine B (RhB) dyes under 50min sunlight irradiation. Moreover, ZnNiNdO/CdS showed intense inhibition activity towards Staphylococcus aureus, Escherichia coli, Proteus vulgaris, and Pseudomonas aeruginosa bacterial strains with maximum inhibition zone diameters 30, 33, 27, and 31mm, respectively. The synergistic effects arising from band alignment can lead to efficient vectorial charge separation, transportation, and lower recombination of photoinduced charge carriers, ultimately boosting photocatalytic and antibacterial performance. The ZnNiNdO/CdS photocatalyst has higher stability up to the 7th cycle towards MB dye with ~ 5% deficit in degradation efficiency. The higher generation of superoxide and hydroxyl radical was confirmed by species trapping experiments responsible for photodegradation of dyes molecules. Furthermore, the results showed that the photocatalytic and antibacterial performance of pristine ZnO can be enhanced by co-doping and tuning energy bandgap.

Novel ZnTi LDH/h-BN nanocomposites for removal of two different organic contaminants: Simultaneous visible light photodegradation of Amaranth and Diazepam

In the present study, a novel heterostructure nanocomposite consisting of hexagonal boron nitride (h-BN) and ZnTi layered double hydroxide was synthesized to remove two organic pollutants simultaneously from the aqueous solution under visible light irradiation at room temperature. ZnTi LDH/h-BN represents a cost-effective reusable material that showed both adsorption and substantial photocatalytic performance in the degradation of amaranth (AM) azo dye and diazepam (DZP) as organic contaminants of water. Various analyses were performed to assess the morphology, characteristic features, and synthesis accuracy of the as-prepared materials that proved the proper formation of the nanocomposite. Additionally, an acceptable reduction was observed in the bandgap of the nanocomposite in comparison with the bandgap of ZnTi LDH. Furthermore, the effect of various parameters, including pH of the solution, contaminant concentration, and catalyst dosage, were studied on the adsorption and photocatalytic activity to find out optimum conditions during the process. Results revealed that the synthesized catalysts had performed exceptionally well in adsorbing and degrading considered pollutants even in removing both from the same solution. The layered structure of the h-BN played a crucial role in providing an available surface area needed for adsorption and better dispersion of the photocatalyst particles, and at the same time, ZnTi LDH reduced AM and DZP by its photocatalytic activity. In the optimal conditions, the simultaneous removal efficiency of the molecule of AM and DZP was measured to be more than 99% and 95%, respectively.

Ag and BiVO4 decorated reduced graphene oxide: A potential nano hybrid material for photocatalytic, sensing and biomedical applications

Recently, the development of multifunctional heterostructured nanocomposites has recieved significant interest due to their numerous applications. In this study, BiVO4, Ag-BiVO4 and Ag-BiVO4-rGO photocatalysts were synthesised using Citrus bergamia through solution combustion technique. Prepared nanomaterials were characterized by PXRD, FTIR, Raman, UV– visible DRS, TEM, SEM and EDX spectroscopy studies. The materials were assessed for photocatalytic MB dye degradation. Ag-BiVO4-rGO photocatalyst was found to degrade MB dye completely in 60 min whereas BiVO4 and Ag-BiVO4 NPs degraded the dye in 150 and 180 min respectively. Photoluminescence spectra evidenced the efficient charge separation in Ag-BiVO4-rGO composite compared to BiVO4 and Ag-BiVO4 NPs. The electrochemical nitrite sensing studies revealed that Ag-BiVO4-rGO composite was a promising electrocatalyst with a significant anodic peak current 57.43 μA at the potential of 0.867 V. The limit of detection of nitrate was observed to be 8.7517 μM. Further, the composite material exhibited better biological activities such as antioxidant, erythrocytes lysis, anticoagulant, anti-platelet and antibacterial properties. The superior properties of Ag-BiVO4-rGO are ascribed to reduction in the energy gap as well as crystallite size by incorporation of Ag into the crystal lattice and presence of rGO. The present study demonstrates a novel approach to develop multifunctional Ag-BiVO4-rGO nano hybrid material for photocatalytic dye degradation, photoluminescence, electrocatalytic nitrite detection and selected biomedical applications.

Molecular-Scale Manipulation of Layer Sequence in Heteroassembled Nanosheet Films toward Oxygen Evolution Electrocatalysts.

Flocculation or restacking of different kinds of two-dimensional (2D) nanosheets into heterostructure nanocomposites is of interest for the development of high-performance electrode materials and catalysts. However, lacking a molecular-scale control on the layer sequence hinders enhancement of electrochemical activity. Herein, we conducted electrostatic layer-by-layer (LbL) assembly, employing oxide nanosheets (e.g., MnO2, RuO2.1, reduced graphene oxide (rGO)) and layered double hydroxide (LDH) nanosheets (e.g., NiFe-based LDH) to explore a series of mono- and bilayer films with various combinations of nanosheets and sequences toward oxygen evolution reaction (OER). The highest OER activity was attained in bilayer films of electrically conductive RuO2.1 nanosheets underlying catalytically active NiFe LDH nanosheets with mixed octahedral/tetrahedral coordination (NiFe LDHTd/Oh). At an overpotential of 300 mV, the RuO2.1/NiFe LDHTd/Oh film exhibited an electrochemical surface area (ECSA) normalized current density of 2.51 mA cm-2ECSA and a mass activity of 3610 A g-1, which was, respectively, 2 and 5 times higher than that of flocculated RuO2.1/NiFe LDHTd/Oh aggregates with a random appearance of a surface layer. First-principles density functional theory calculations and COMSOL Multiphysics simulations further revealed that the improved catalytic performance was ascribed to a substantial electronic coupling effect in the heterostructure, in which electrons are transferred from exposed NiFe LDHTd/Oh nanosheets to underneath RuO2.1. The study provides insight into the rational control and manipulation of redox-active surface layers and conductive underlying layers in heteroassembled nanosheet films at molecular-scale precision for efficient electrocatalysis.

Synergistic S-Scheme mechanism insights of g-C3N4 and rGO combined ZnO-Ag heterostructure nanocomposite for efficient photocatalytic and anticancer activities

The g-C3N4/rGO/ZnO-Ag (GCRZA) composite photocatalyst (PC) prepared by the facile hydrothermal method was effectively studied. The structural, morphological and optical, properties of as-synthesized materials were characterized by various characterization techniques. Photocatalytic activity of the as-prepared composite was examined using rhodamine B and methylene blue mixed (RhB+MB) aqueous dye under UV–visible light irradiation for 100 min. The GCRZA composite displayed a better photocatalytic performance against MB dye (90.04%) and RhB dye (83.45%) degradation performance. Moreover, the GCRZA composite PCs exhibited higher photocatalytic activity than pristine g-C3N4. The ultimate photocatalytic property was attained by implementating of g-C3N4/rGO in ZnO-Ag heterostructure, which could effectively decrease the optical bandgap and high visible-light absorption ability with suppressed e−/h+ recombination rate. After the five consecutive photocatalytic recycles, the GCRZA composite PC showed good stability without structural changes. Furthermore, the IC50 values showed that GCRZA nanocomposite (NC) has a higher cytotoxicity effect than g-C3N4/ZnO-Ag, g-C3N4/rGO and g-C3N4 against both HeLa and MCF-7 cell lines. As a result, this combination of nanocomposite has proven to exhibit higher photocatalytic and anticancer activity. Eventually, it may prove to be an effective tool for eradicating dye pollution from wastewater, and a way to prevent cancer mediated diseases in the cosmetics and pharmaceutical industries.

Kinetically induced one-step heterostructure formation of Co3O4-Ni(OH)2-graphene ternary nanocomposites to enhance oxygen evolution reactions

Ternary Co3O4-Ni(OH)2-graphene hybrid nanocomposites (NCs) can be fabricated using a facile, room-temperature kinetic spray process in a single step. The fabricated heterostructure electrodes are optimized to enhance the oxygen evolution reaction (OER) in 1.0 M KOH. The deposited films exhibit a mixture of nanosheet and nanoflake morphologies. Raman spectra reveal improvements in various disorder-related modes in the hybrid NCs due to the nanometer scale and the transformation of graphite-stacked layers into thin graphene nanosheets. X-ray photoelectron spectra indicate that strong synergy improvements in the heterostructure NCs are associated with a downshift of the active state’s binding energies. Optimal Co3O4-Ni(OH)2-graphene hybrid ternary NCs exhibit the smallest OER overpotential of 262 mV @ 10 mA·cm−2, the lowest Tafel slope of 32 mV·dec−1, and long-term stability of 25 h at a polarization current of 50 mA·cm−2.

Sandwich-like superstructure of in-situ self-assembled hetero-structured carbon nanocomposite for improving electrocatalytic oxygen reduction

Developing efficient and highly low-cost electrocatalysts for oxygen reduction reaction (ORR) is highly desirable and challenging for renewable energy devices. In this work, a novel sandwich-like heterostructured nanocomposite was facilely constructed via incorporation of Co9S8 nanoclusters/Co3[Co(CN)6]2 nanocubes in N,S-doped carbon multilayers (Co9S8/Co3[Co(CN)6]2/N,S-CMLs) by a one-pot coordination-modulated pyrolysis of a mixture containing dicyandiamide, Co(NO3)2 and Evans blue at 800 °C. The control tests demonstrated critical roles of the pyrolysis temperature played on the final morphology and shape, and discussed the formation mechanism in detail. The as-prepared catalyst exhibited appealing electrocatalytic performance for ORR with a more positive onset potential (Eonset = 0.96 V vs. RHE) and half-wave potential (E1/2 = 0.87 V vs. RHE) in 0.1 M KOH electrolyte, far outperforming other home-made catalysts and commercial Pt/C. This work opens a new avenue to prepare efficient, cost-effectiveness and stable electrocatalysts in sustainable energy storage and conversion devices.

Co[sbnd]Fe hydroxyoxalate nanosheets chemically bonded with reduced graphene oxide as High-performance anode for lithium-ion batteries

Transition metal layered double hydroxide (LDHs) materials are promising anodes for high-energy lithium-ion batteries (LIBs) due to their high specific capacities. However, the conductivity and the influence of intercalated anions are key issues for improving their electrochemical performances. Herein, a C2O42− intercalated CoFe-LDH nanosheets anchored on reduced graphene oxide (Co0.83Fe0.17(OH)2(C2O4)0.085·0.08H2O/rGO, CFO) composite was successfully synthesized for the first time by a two-step hydrothermal process. Graphene provides abundant nucleation sites for CoFe-LDH and forms the interconnected porous network skeleton. The intercalated C2O42− ions widen the interlayer spacing of CoFe-LDH to 0.92 nm, which can enhance the transportation of lithium ions. The lithium storage mechanism was proved that the CFO was transformed into a heterostructure nanocomposite (metal hydroxide and lithium oxalate) after discharge, and the high-valent carbon in lithium oxalate was electrocatalytically converted into low-valent carbon. This results in fast electrochemical reactions and high capacity. What’s more, the CFO shows a high reversible capacity (1603 mAh g−1 after 120 cycles), and long-term cycle stability under high current density (CFO delivers a reversible capacity of 860 mAh·g−1 after 1000 cycles at 4 A·g−1). This work provides a new anodes material for application in high-energy LIBs.

Maghemite nanoparticles decorated semiconducting graphitic carbon nitride hetero-structured nanocomposite: Facile synthesis, characterizations and its visible light active photocatalytic system for removal of hazardous organic pollutants from aqueous solutions

Hetero-structured nanocomposite consisting of graphitic carbon nitride host, decorated by γ-phase iron oxide, maghemite (γ-Fe2O3@G-CN) was synthesized in different mass contents of γ-Fe2O3 (5%, 10% and 20%) in the composite, by the method of nanosecond pulsed laser fragmentation, and defect engineering in liquid for the removal of hazardous organic pollutants from aqueous solutions. The elemental, structural, and morphological characterizations of the synthesized nanocomposites by XPS, XRD, TEM, and HR-TEM exhibited the proper anchoring of γ-Fe2O3 on the graphitic carbon nitride polymeric network. Also, the diffuse reflectance spectra, and the room temperature photoluminescence spectra respectively revealed that the presence of γ-Fe2O3 in graphitic carbon nitride brought about the enhanced and extended visible light absorption, and reduced recombination of photo induced electron hole pairs, the characteristics desired in a good photo-catalyst. Moreover, this composite material exhibited the z-scheme photo catalytic mechanism, where the more energetic electrons and holes in the composite band structure mediate the redox reaction in the photo-catalysis. The photo-catalytic efficiency of γ-Fe2O3@G-CN nanocomposite was evaluated in the photo-catalytic degradation of methyl blue (MB), and rhodamine-B (Rh-B) cationic dyes under visible light irradiations. For both the degradation processes, all the variants of γ-Fe2O3@G-CN nanocomposite consistently showed the enhanced photocatalytic efficiency with respect to pure GCN, with the maximum efficiency recorded for 10% γ-Fe2O3 in γ-Fe2O3@G-CN nanocomposite.

A novel approach for fabrication ZnO/CuO nanocomposite via laser ablation in liquid and its antibacterial activity

Pulsed laser ablation in liquid (PLAL) has verified its surpassing advantages in the fabrication of several high purity nanostructured metals and metal oxides. In this work, ZnO/CuO heterostructure nanocomposites have been fabricated by laser ablation a Q switched Nd: YAG laser beam (1064 nm, 10 Hz, pulse energy and pulse with 30 mJ and 10 ns) is focused on the surface of the ZnO thin film for 10 min. The fabricated ZnO/CuO nanocomposite was then characterized using transmission electron microscopy (TEM), UV–vis spectrophotometer, X-ray diffraction (XRD), and Raman spectroscopy to investigate the structural, compositional, and optical properties of the fabricated nanocomposite. The synthesized nanocomposites were evaluated as antibacterial agents against both the gram-positive bacterium S. aureus subsp. aureus ATCCBAA-977, and the gram-negative bacteria E. coli ATCC8739, K. pneumoniae subsp. pneumoniae ATCC700603, and P. aeruginosa ATCC27853. The as-fabricated ZnO/CuO nanocomposite demonstrated outstanding antibacterial activity except in the case of K. pneumoniae subsp. pneumoniae ATCC700603 while the maximum activity was observed against E. coli ATCC8739.

CaSnO3 coupled g-C3N4 S-scheme heterostructure photocatalyst for efficient pollutant degradation

The perovskite CaSnO3/g-C3N4 heterostructure nanocomposite was successfully prepared via facile solid-state route. The properties of morphology, structural, optical, functional, elemental, surface, electrochemical and photocatalytic performances were investigated. The synthesised CaSnO3 (CS) nanoparticles were grafted on the g-C3N4 nanosheets and their photocatalytic performance were determined. The introduction of g-C3N4 possesses solid-solid intimately contacted interfaces with CS that provides more transport paths and effectively improve the separation of photogenerated electrons and holes (e−/h+). Thus, the formation of CaSnO3/g-C3N4 (CGN) heterostructures exhibits with tunable optical bandgap and suppresses the charge recombination process that leads to improve the photocatalytic efficiency. Compared with bare CS the CGN photocatalyst achieves 95% of degradation efficiency over methylene blue (MB) dye in 120 min of UV–visible light irradiation. The possible photocatalytic degradation mechanism was discussed. Furthermore, the CGN photocatalyst has been utilized for 4 repeated runs of experiments which shows good stability and reusability after the degradation experiments.

Highly Efficient and Sustainable ZnO/CuO/g-C3N4 Photocatalyst for Wastewater Treatment under Visible Light through Heterojunction Development

Dye-containing pollutants are currently a threat to the environment, and it is highly challenging to eliminate these dyes photocatalytically under visible light. Herein, we designed and prepared a ZnO/CuO/g-C3N4 (ZCG) heterostructure nanocomposite by a co-crystallization procedure and applied it to eliminate pollutants from wastewater via a photocatalytic scheme. The structural and morphological features of the composite confirmed the formation of a ZCG nanocomposite. The photocatalytic capability of the ZCG photocatalyst was investigated via the decomposition of methylene blue dye. The outstanding activity level of 97.46% was reached within 50 min. In addition, the proficiency of the ZCG composite was 753%, 392%, 156%, and 130% higher than photolysis, g-C3N4, CuO, and ZnO, respectively. Furthermore, the photodeterioration activity on Congo red was also evaluated and found to be excellent. The enhanced catalytic achievement is attributed to the construction of heterojunctions among the constituent compounds. These properties boost the charge transfer and decrease the recombination rate. Moreover, the reusability of the ZCG product was explored and a negligible photoactivity decline was detected after six successful runs. The outcomes suggest the as-prepared nanocomposite can be applied to remove pollutants, which opens a new door to practical implementation.

Study on the electronic band structure of ZnO–SnO2 heterostructured nanocomposites with mechanistic investigation on the enhanced photoluminescence and photocatalytic properties

Study on the electronic band structure of ZnO–SnO2 heterostructured nanocomposites with mechanistic investigation on the enhanced photoluminescence and photocatalytic properties

The heterostructured nanocomposite of EPS/PVA/Ag-TiO2 for sewage treatment by COD removal

The heterostructured nanocomposite of EPS/PVA/Ag-TiO2 for sewage treatment by COD removal

Ru(tmphen)3]2[Fe(CN)6] and [Ru(phen)3][Fe(CN)5(NO)] complexes and formation of a heterostructured RuO2-Fe2O3 nanocomposite as an efficient alkaline HER and OER electrocatalyst.

Water electrolysis is one of the most capable processes for supplying clean fuel. Herein, two novel ionic Ru(II)-Fe(II) complexes, [Ru(tmphen)3]2[Fe(CN)6] and [Ru(phen)3][Fe(CN)5(NO)], where tmphen = 3,4,7,8-tetramethyl-1,10-phenanthroline and phen = 1,10-phenanthroline, were synthesized and characterized by UV-Vis spectroscopy, elemental analysis, FT-IR, and single-crystal X-ray structural analysis. By thermally decomposing the [Ru(tmphen)3]2[Fe(CN)6] complex at 600 °C for 4 h, a heterostructured RuO2-Fe2O3 nanocomposite was fabricated through a facile one-pot treatment and then characterized by FT-IR, XRD, FT-Raman, UV-Vis (DRS), ICP-OES, FE-SEM, TEM, TGA/DTG, BET, and XPS analyses, which revealed the formation of highly crystalline RuO2-Fe2O3 nanoparticles with an average size of 8-12 nm. The prepared nanocomposite was an efficient heterostructured electrocatalyst for performing water-splitting redox reaction processes, including hydrogen and oxygen evolution reactions (HER and OER) in alkaline solutions. In this regard, RuO2 and Fe2O3 samples were also prepared through thermal decomposition of [Ru(tmphen)3](NO3)2 and K4[Fe(CN)6] precursors, respectively, as control experiments to compare their HER and OER electrocatalytic activity with that of the RuO2-Fe2O3 nanocomposite. Specifically, the RuO2-Fe2O3 nanocomposite exhibited significant electrocatalytic performance, generating 10 mA cm-2 current density at -148 and 292 mV overpotentials, and the Tafel slope results from fitting the LSV curves to the Tafel equation were -43 and 56.08 mV dec-1 for the HER and OER, respectively. Therefore, the heterostructured RuO2-Fe2O3 nanocomposite can be viewed as a bi-functional electrocatalyst for HER and OER because it exploits the synergistic effects of heterostructures and active sites at its interface.

NOVEL HETEROSTRUCTURE BaxTiO3-ZnXFe2O4 NANOCOMPOSITE: A QUANTITATIVE STUDY

A novel Barium Titanate-Zinc ferrite (BaxTiO3-ZnXFe2O4) heterostructure nanocomposites are synthesized at temperatures less than 500ºC which is the major theme of the present research. The synthesis technique is adapted in such a way that the size of the particle is governable. In this research two dissimilar ratios of BTO (hard-site) and ZFO (soft-site) composites are synthesized (H-S 90:10, H-S 60:40) and quantitatively analyzed for their exclusive structural, textural, spectroscopic, and optical properties. With XRD data, structural refinement has been carried out showing 49 % of harder-BTO phase (Triclinic) and 51% of softer-ZFO phase (Cubic) for H-S 90:10 and similarly 78% of harder-BTO phase and 22% of softer-ZFO phase in the H-S 60:40 composite respectively. Very small particles of 6nm are found which is confirmed by SEM histogram and sample purity was determined using EDX analysis. Proofs for the formation of nanocomposites and the existence of Tetrahedral and Octahedral phases for each sample were given using FTIR Spectroscopy. From UV spectrometer data, Tauc’s plot is used to find the wide energy band gap which is observed to be 2.6651 and 3.1971 eV, thus proving that these composites can present themselves as a budding candidate for nano-level optoelectronic devices and other photovoltaic applications.

NIR light-triggered peroxynitrite anion production via direct lanthanide-triplet photosensitization for enhanced photodynamic therapy.

Peroxynitrite anion (ONOO-), a product derived from reaction between reactive oxygen species (ROS) and nitric oxide (NO), is considered to be a more toxic reactive species than most ROS for cancer photodynamic therapy (PDT). To promote the PDT effect, a viable method is to develop rational strategies for efficient ONOO- generation at targeted tumor sites. Herein, a heterostructure nanocomposite containing ZnO-coated lanthanide nanoparticles (LnNPs) is reported for ONOO--based PDT. In this nanocomposite, Nd3+-doped LnNPs are employed to realize efficient NIR-light-triggered ROS generation by activating the triplet state of chlorin-e6 (Ce6) photosensitizers via a direct lanthanide-to-triplet sensitization mechanism. Meanwhile, ZnO in the composite catalyzes the decomposition of S-nitrosoglutathione (GSNO) to generate NO in the tumor microenvironment. The coupled system allows the combination of photo-induced ROS and NO to produce ONOO-, leading to drastically promoted cancer cell apoptosis and tumor growth inhibition. This study establishes a new apoptosis-inducing PDT agent, which is potentially active in drug resistant malignancies.

Investigation of photocatalytic and DNA interaction of novel heterostructured GO/Bi2O3/ZnO nanocomposite

In the present work, we synthesize novel heterostructured nanocomposites of GO/Bi2O3/ZnO (GBZ), GO/Bi2O3 and GO/ZnO adopting by solid state method and using nano graphene oxide (GO), Bismuth oxide (Bi2O3) and Zinc oxide (ZnO). The desire synthesized nanocomposites were characterized and established by UV–visible spectroscopy, X-ray diffraction (XRD), Scanning electron microscopy (SEM), Transmission electron microscopic (TEM) and Furrier transform infrared spectroscopy (FT-IR) techniques. The average grain, particle and crystallite sizes of GBZ were found to be 100 ± 5, 50 ± 2 and 48 ± 2 nm, respectively. The most exciting feature of the compositions is that the nanoparticles were distinctly shaped with effective photocatalytic activity against crystal violet (CV) degradation in the presence of sunlight under normal conditions. Among all the composites, GBZ has more catalytic degradation efficiency (85 %) than other catalysts, including different dyes and its rate constant (k) is 17.8 × 10−3min−1 against CV. This study also includes the common ion effect of the catalysts. The GBZ was easily recoverable by a simple filtration method and recycled without significant loss of photocatalytic activity. In the present work we first time report the DNA interactions with GBZ and show good binding results with a distinctly red shift from 258.34 to 269.32 nm. The advantages of these nanocomposites were synthetic process, high yield, solvent-free condition, reusable, cost-effective, nontoxic, short-time reaction and less hazardous materials under a green context.

Fabrication of CdSe/ZnIn2S4 modified TiO2 nanotube composite and its application in photoelectrochemical cathodic protection

In order to obtain a TiO2 nanocomposite film with enhanced photoelectrochemical properties for corrosion protection of metals, a TiO2 nanotube film was fabricated on a Ti substrate via anodization, then ZnIn2S4 nanosheets and CdSe nanoparticles were sequentially deposited on the TiO2 film by hydrothermal treatment and electrodeposition, respectively. The CdSe/ZnIn2S4 co-modified TiO2 heterostructured nanocomposite film showed remarkably enhanced visible light absorption and photoelectrochemical properties. Under white light irradiation, the photocurrent density of the nanocomposite film in the mixed solution with 0.1 M Na2S and 0.1 M Na2SO3 was 33 times higher than that of the TiO2 film. The nanocomposite could negatively shift the potential of the coupled 403 stainless steel immersed in a 0.5 M NaCl solution by 440 mV, showing efficient photoelectrochemical cathodic protection.

Sol–gel synthesis of mesoporous NiO/ZnO heterostructure nanocomposite for photocatalytic and anticorrosive applications in aqueous media

Nanocomposites (NCs) of p-type NiO/n-type ZnO heterojunction with varied NiO content (0−10) wt% were produced by spreading NiO nanoparticles (NPs) on the ZnO (NPs) surface by sol-gel technique with Triton X-100 as a structuring & templating agent. The crystalline phase, structure, characterization, and surface morphology of the gel powde0r of the produced NiO/ZnO nanocomposites were investigated using different spectroscopic techniques such as FTIR, XRD, FESEM, EDX, HRTEM, BET and UV–Vis DRS. The photocatalytic performance of the produced NiO/ZnO nanocomposites was estimated by continuously degrading the methylene blue dye (MB) as an organic contaminant in aqueous media. The effects of several factors, such as dopant concentration, pH, photocatalytic dose, point of zero charge (PZC), and chemical oxygen demand (COD) were assessed and discussed. When pure ZnO (NPs) is compared to NiO/ZnO (NCs), both exhibit superior photocatalytic activity under UV and sunlight irradiation. The corrosion resistance of the NiO/ZnO (NCs) gel coatings was assessed via potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS). The photodegradation data shown that the NiO/ZnO (5 wt%) semiconductor is the best photocatalyst for methylene blue dye (MB) degradation among the manufactured semiconductors. Furthermore, when compared to alternative gel coatings and the untreated surface at various doping doses, the gel coating based on NiO/ZnO (NCs) with a concertation of (5 wt%) displayed the highest activity as a coating system for aluminum electrode. In addition, increasing the layer thickness of NiO/ZnO (NCs) gel films and co-dopant concentration in coating systems increase corrosion resistance. AFM micrographs revealed the creation of a protective multilayer of NiO/ZnO (NCs) coating films on the surface of aluminum. The experimental and spectral results confirmed that the synthesized novel mesoporous mixed NiO/ZnO (NCs) had potential photocatalytic and anticorrosive behaviors.