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A visible light driven 1D/2D-NiMoO4/BiOI nanocomposite photocatalyst was constructed by single step solvothermal method. Here, various composition of NiMoO4/BiOI nanocomposites were prepared by loading different amounts of NiMoO4 (1, 2, 3 wt %) to the BiOI. Among the as-prepared photocatalysts, 1 wt % of NiMoO4 on BiOI (NMBI-1) showed superior photocatalytic activity (92.7 %) under visible light irradiation. On analysis, the optimized NMBI-1 exhibited a lower bandgap energy value of 1.64 eV and also found to show around 2 and 3.7-times higher degradation ability for the removal of MB than the pure NiMoO4 and BiOI respectively. In addition, the optimized NMBI-1 nanocomposite photocatalyst exhibited excellent photostability and recyclability properties. The charge carriers on the interface of the NiMoO4 and BiOI enabled the easy transfer via the newly formed heterojunction, thereby increasing the photocatalytic performance. Additionally, the radical scavengers such as h+ and .OH were found to be the major species in the removal of MB under visible light illumination. Therefore, the 1D/2D-NiMoO4/BiOI nanocomposite photocatalyst materials could possibly be considered for the wastewater remediation processes.

Supercapacitors are progressively being utilized for storage systems in sustainable nanotechnologies. A NiCoS nanostructure was synthesized on nickel foam by an in situ one-pot hydrothermal method at different reaction temperatures (80, 100, and 120 °C) keeping other reaction parameters such as pH and reaction time constant for supercapacitor applications. The SEM report revealed a plate-like nanostructures of NiCoS on nickel foam (NiCoS/NF). The electrode prepared at 100 °C exhibits better electrochemical activities compared to electrodes prepared at 80 and 120 °C. The integrated binder-free NiCoS/NF electrode for supercapacitor, optimized at 100 °C, manifested a large specific capacitance of 3309 mF cm−2 at a current density of 1 mA cm−2 with a notable rate capability of 427 mF cm−2 even at 10 mA cm−2. The asymmetric supercapacitor fabricated with optimized NiCoS/NF prepared at 100 °C exhibited an exceptionally high energy density of 2.04 mW h cm−3 at a power density of 42.64 mW cm−3.

A series of ternary ZnO hollow sphere/carbon quantum dots/reduced graphene oxide (ZnO/CQDs/r-GO) nanocomposites were successfully prepared via solvothermal technique in the presence of the polyethylene glycol 400 (PEG 400) as a solvent. The structural details of as-prepared ZnO/CQDs/r-GO nanocomposites were characterized by powder X-ray diffraction analysis. The morphological properties of the composite were analyzed using field emission scanning microscopy (FE-SEM). The visible light absorption ability of the as-prepared pristine and ternary nanocomposites was examined using UV–visible (UV–Vis) spectrophotometry. The photocatalytic activity of ZnO, ZnO/CQDs, ZnO/r-GO, and ZnO/CQDs/r-GO nanostructures were evaluated for the degradation of organic pollutants such as methylene orange (MO), rhodamine B (RhB), and methylene blue (MB). The different composites with various amounts of reduced graphene oxide (r-GO) and carbon quantum dots (CQDs) were synthesized to enhance photocatalytic activity. The ZnO/CQDs/r-GO composites showed excellent potential for photocurrent generation compared with ZnO, ZnO/CQDs and ZnO/r-GO under-stimulated sunlight. The effect of various parameters such as the effect of reaction temperature, catalyst concentration, pH, and concentration of MB dye has been also studied. The photo-assisted catalytic degradation properties of the catalyst after five cycles exhibit high stability.

ZSM-5:CeO2 nanocomposites were prepared by two-step hydrothermal method in combination with the wet impregnation method. The synthesized nanocomposites were characterized by XRD, FESEM, TEM, EDX, elemental mapping, FTIR and UV–vis analysis. The bandgap investigations were done using tauc plot and the bandgap of ZSM-5 has been reduced from 3.90 to 3.15 eV upon CeO2 loading. The synthesized nanocomposites were tested for photocatalytic activity under a halogen lamp and the effect of CeO2 loading on ZSM5 has been examined. Among the various nanocomposites synthesized, ZSM-5:CeO2 25 wt% exhibited better methyl orange degradation of about 95.6% with an initial dye concentration of 10 mg/l, pH 7, 100 mg of photocatalyst under halogen lamp for 75 min. Additionally, the effect of various reaction parameters like dye concentration (10–25 mg/l), photocatalyst dosage (25–125 mg), and pH (3–9) was probed to get better performance. Tapping experiments were conducted with various radical scavengers to get insight into the key active species responsible for the photodegradation of methyl orange. The result portrays the importance of hydroxyl radical for the degradation of methyl orange dye. Cycle test and stability studies showed that the photocatalyst was stable even after four cycles. In summary, ZSM-5:CeO2 nanocomposites can be a suitable photocatalyst for numerous applications in the field of photodegradation of organic contaminants.

Bismuth sulfide (Bi2S3) nanorods have been prepared using a simple and low-cost reflux method. This method is easy to handle and opens up a way to manufacture photocatalytic pigment at a low cost. The Bi2S3 catalyst was subjected to X-ray diffraction (XRD), UV–Visible spectroscopy (UV–Vis), scanning electron microscope, high-resolution transmission electron microscopy, FT-IR spectroscopy, thermogravimetric analysis (TG/DTA), and X-ray photoelectron spectroscopy. The structures of the Bi2S3 nanorod have been investigated and were seen to be orthorhombic. The electron microscopic observations showed that surfactants greatly affect the morphologies of the as-prepared Bi2S3 samples. The XRD and TEM results confirmed that the Bi2S3 nanorods have a high surface area and are good crystallinity. TEM measurements revealed that the average breadth and length is 75 nm and 385 nm for Bi2S3 nanorods prepared using NaOH. The uniform one-dimensional Bi2S3 nanorods are due to the presence of NaOH which controls the nucleation and growth process of Bi2S3 nanorods. The photocatalytic activity of the Bi2S3 nanocrystallites has been estimated by the degradation of methylene blue (MB) under the irradiation of halogen light. It was noted that the absorption peak corresponding to MB reduced indicating the photocatalytic nature of the sample. In these conditions, the maximum degradation of the dye was achieved within 140 min for KOH added Bi2S3 samples and the photodegradation efficiency is 87.98%. A possible photocatalytic reaction mechanism of the Bi2S3 samples has also been proposed.

Hexagonal phase zinc oxide (ZnO) nanostructures were synthesized via hydrothermal method and annealed at different temperatures viz., 200, 400, 600, 800 and 1000 °C. The prepared nanostructures were characterized by XRD, FTIR, FESEM, HR-TEM, UV-DRS and XPS techniques. The crystallite sizes of the prepared nanomaterails were calculated by Williamson–Hall plots method. The ZnO annealed at 200 °C showed a crystallite size of 18.7 nm while the ZnO annealed at °C showed a 46.2 nm. It is observed that when increasing the annealing temperature the crystallite sizes were increased due to induced growth of crystallites during annealing process. Moreover, the band gaps of the ZnO annealed at different temperatures showed a decreasing trend with increasing annealing temperatures. The photocatalytic performances were studied by analyzing the degradation of methylene blue in an aqueous solution. ZnO annealed at 1000 °C exhibited better photocatalytic activity (94%) due to enhanced crystallinity, comparatively lower bandgap and high oxygen vacancy.

The development of efficient, scalable, and economically viable electrode materials with high specific capacitance is of great significance for supercapacitor applications. Herein, α-Fe2O3 nanoparticles, α-Fe2O3/rGO, and α-Fe2O3/SnO2/rGO nanocomposite were synthesized by a one-step hydrothermal method. Different characterization techniques were used to study the physical and chemical properties of the prepared materials. The powder XRD measurement revealed that the formation of the ternary composite without any impurities. As characterized by SEM and TEM techniques, both α-Fe2O3 and SnO2 nanoparticles were embedded on two-dimensional reduced graphene oxide sheets. The electrochemical properties of the prepared electrode materials were studied by cyclic voltammetry and galvanostatic charge/discharge, and impedance spectroscopy techniques in a 6 M KOH electrolyte solution. All the electrode materials exhibit Faradic reaction peaks in CV curves which imply the pseudocapacitive nature of the prepared materials. The ternary α-Fe2O3/SnO2/rGO nanocomposite demonstrated the enhanced specific capacitance of 821 Fg−1 at 1Ag−1 than that of α-Fe2O3 nanoparticles (373 Fg−1 at 1Ag−1), and α-Fe2O3/rGO (517 Fg−1 at 1Ag−1) nanocomposite with excellent cyclic retention (98.7%) after successive 10,000 cycles. This improved electrochemical performance of ternary α-Fe2O3/SnO2/rGOnanocomposite is mainly attributed to the surface properties of nanostructures of metal oxides and an excellent conductive network. Moreover, the asymmetric supercapacitor (ASC) device was fabricated using the ternary α-Fe2O3/SnO2/rGOnanocomposite as the anode material and rGO as the cathode material. The ASC device showed an energy density of 17 Wh Kg−1 at a power density of 3585 W kg−1 and retains 94.52% capacitance after successive 5000 cycles at a current density of 10Ag−1.

In this study, pure ZnO and g-C3N4 were synthesized using coprecipitation and simple calcination methods, respectively. Further, ZnO is impregnated on a g-C3N4 surface with 10, 20 & 30 weight percentages, respectively. Besides, these materials are characterized by various physicochemical techniques such as PXRD, UV-Vis-DRS, TEM, PL, and FT-IR, etc. Vitally, as-prepared materials, catalytic activity was tested for removal of Rhodamine B and 4-nitrophenol from the wastewater under visible light irradiation. Among all these catalysts, 20 wt% ZnO/g-C3N4 showed better activity and showed 67% and 75% mineralization. The graphical abstract simply represents the proposed mechanism for photocatalytic removal of 4-nitrophenol and Rhodamine B with ZnO/g-C3N4 composite. ZnO was a hexagonal plate type structure and g-C3N4 shows a sheet-type structure.

In this work, the corrosion inhibition performance of 1,2,3 – Benzotriazole (BTA) as an organic inhibitor for cold rolled mild steel in an acidic medium was investigated. For this, different loading ratios of BTA were utilized and their efficiency as corrosive inhibitor either within the coating film or within the electrolyte was discussed. The first set of the samples was fabricated by the incorporation of 0.1 wt.%, 0.5 wt.%, and 1.0 wt.% BTA within the acrylic polymer host matrix. The influence of BTA to the structural, optical, and adhesion properties of the acrylic coating films was examined. The obtained results revealed no significant changes resulted from the addition of different concentrations of BTA. The other set of the samples was developed by dissolving different concentration of BTA specifically, 100 ppm, 500 ppm, and 1000 ppm within the acidic electrolyte. All tested substrates were coated with acrylic based coating systems in the presence of polyisocyanate (NCO) as a curing agent. 0.5 M H2SO4 was used as the corrosive electrolyte and the corrosion protection performance of the two sets of the samples was investigated via electrochemical impedance spectroscopy (EIS). The obtained results confirmed the way of introduction influenced the performance of the BTA as a corrosion inhibitor. The best corrosion protection and the intact behavior was observed by adding 0.1 wt.% of BTA within the acrylic coating film even after 30 days of exposure of coated substrate to H2SO4 solution.

Novel hollow sphere morphologied zinc sulphide@carbonaceous aerogel (ZnS@CA) composites with different ZnS content were fabricated using a simple hydrothermal carbonization treatment following by a facile in situ growth method. The fabricated composites were used as catalysts for chemical degradation of the methylene blue (MB) and for hydrogen evolution. Our photocatalytic studies are found, from the photocatalytic results obtained by different ZnS@CA materials, that 55 wt%ZnS@CA exhibits the excellent photocatalytic performances for MB degradation and the highest rate of hydrogen production that are correspondingly 1.7- and 8.1-fold higher than that of pure ZnS. This improved photocatalytic performance could be mainly attributed by unique 3D catenulate carbon networks, which can be highly favorable to disperse of ZnS on the surface of CA. An synergetic properties between CA and ZnS could be highly beneficial to the photo-generated electron–hole separation. The hollow microsphere structured ZnS nanoparticles allow multi-reflections of light within the interior cavity and increases the capture efficiency of visible light. A possible photocatalytic mechanism of the main active radicals has also been proposed. This work opens up the new prospects for a low-cost biomass-based sulfide photocatalysts used for the environmental purification and hydrogen generation.

Zeolitic imidazolate framework ZIF-23 was prepared and used as catalyst for the solventless synthesis of cyclic carbonate from CO2 and propylene oxide with or without TBAB co-catalyst. ZIF-23 catalysts were prepared by a solvothermal or microwave method and they were characterized by various physicochemical techniques such as XRD, FT-IR, BET, TGA, and FE-SEM. The effects of reaction parameters such as temperature, reaction time, CO2 pressure, and co-catalyst on the reactivity of catalyst were investigated. ZIF-23 was recyclable up to four times without any considerable loss of its initial activity. Reaction mechanism containing the role of ZIF-23 with TBAB co-catalyst was also proposed.

Ionic liquids (ILs) immobilized onto a structurally modified Merrifield peptide resin (MPR) were prepared through the reaction of imidazole with alkoxylated MPR. Elemental analysis and scanning electron microscopy (SEM) observations showed that the immobilized IL groups were effectively incorporated on the support. The MPR-supported ILs (MPR-ILs) proved to be effective heterogeneous catalysts for the synthesis of glycerol carbonate (GC) from glycerol and urea. MPR-ILs with longer alkyl chain linkers and fewer sterically hindered counteranions resulted in higher conversion of glycerol. High temperature, high degree of vacuum and the presence of zinc oxide co-catalyst were favorable for glycerol conversion. The MPR-ILs could be reused in up to three consecutive runs without significant loss of their catalytic activity.

Ionic liquids immobilized onto structurally modified Merrifield peptide resin (MPR) were prepared through the reaction of imidazole with alkoxylated MPR. Elemental analysis and SEM images showed that the immobilized ionic liquid groups were well incorporated onto the support. The MPR-supported ionic liquids (MPR-IL) proved to be effective heterogeneous catalysts for the solvent-free synthesis of a cyclic carbonate from allyl glycidyl ether (AGE) and carbon dioxide. MPR-ILs with longer alkyl chain linkers and sterically less hindered counteranions had higher conversions of AGE. High temperature, high carbon dioxide pressure and the presence of zinc halide co-catalyst were favorable for AGE conversion. MPR-IL can be reused for the reaction through up to three consecutive runs without significant loss of its catalytic activity.

In this study, we prepared periodic mesoporous organosilica(PMO) materials from 4,4-bis(triethoxysilyl)biphenyl, 1,4-bis(triethoxysilyl)benzene and bis[3-(trimethoxysilyl)propyl]amine as precursors and investigated on their adsorption behavior of various amino acids as a guest material under various conditions such as different kinds of PMOs as absorbents, various concentrations of amino acids and pH. For amino acids, we tested glycine, L-lysine, and isoleucine. Adsorption of various amino acids on PMOs has been characterized by a UV–Vis spectroscopy using the ninhydrin reaction. The adsorption behavior was strongly dependent on the isoelectric point and hydrophobicity of the PMO as well as the hydrophobicity of an amino acid.

The adsorption of cytochrome c has been investigated using two different types of hydrophobic periodic mesoporous organosilicas (PMOs) that have been produced under mild reaction conditions using 1,4-bis(triethoxysilyl)benzene (PMO-benzene) and 4,4′-bis(triethoxysilyl)biphenyl (PMO-biphenyl) as the precursors. For comparison studies, the adsorption of cytochrome c has also been investigated using mesoporous SBA-15 as an absorbent. Mesostructured PMOs and SBA-15 have been characterized by small-angle X-ray scattering (SAXS), N2-adsorption/desorption and transmission electron microscope (TEM). The adsorption rates of the hydrophobic PMOs have been compared to that of SBA-15 at both pH 7.0 and pH 9.6. From the adsorption studies, it is found that PMO-biphenyl has more hydrophobicity than PMO-benzene and showed higher adsorption capacity to cytochrome c as compared to PMO-benzene.

We report the effect of the amount of the mesoporous material, SBA-15, on the basic traits of fully aliphatic polyimides (API). For this purpose, water soluble, fully aliphatic poly(amic acid) triethyl amine salts (PAA(s)) were prepared and mixed with various amounts of SBA-15. Fully aliphatic polyimide hybrid composites containing the SBA 15-type mesoporous silica were synthesized successfully from bicyclo [2.2.2] oct-7-ene-2,3,5,6-tetracarboxylic dianhydride and alicyclic diamine, 4,4′-methylene bis(2-methylcyclohexylamine). The structure of the hybrid composites was confirmed by IR spectroscopic analysis. Scanning electron microscopy revealed the morphology of the compounds. The hybrid composites exhibited good thermal stability, reasonable transparency, and a low dielectric constant.

The direct incorporation of vanadium into the three-dimensional (3-D) cubic Ia3d mesostructure designated as V-KIT-6 was prepared, and the material obtained therein showed a very high specific surface area of ~1,000 m 2 /g with tunable pore diameters in a narrow distribution of sizes, ~5.7 to 6.0 nm. The coordination and nature of the V sites in V-KIT-6 were characterized by 51 V-spin-echo NMR analysis. It shows that after calcination, the V 4+ species are totally oxidized to the V 5+ state with 4- and 6-coordinated V-O environments in a highly dispersed state with much less crystalline V2O5 formation. The calcined V-KIT-6 materials showed excellent catalytic activity in the direct oxidation of styrene using tert-butyl hydroperoxide (TBHP) as an oxidant.

Three dimensional (3-D) cubic KIT-6 with directly incorporated vanadium was hydrothermally synthesized by using Pluronic P123 and n-butanol as the structure-directing mixture, tetraethyl orthosilicate (TEOS) as the silica source and NH4VO3 as the vanadium source. The molar composition was varied in the range of 0.017 P123/0.08–2.4 V/1.0–2.0 TEOS/1.31–1.70 BuOH/1.83–3.00 HCl/195 H2O. The orderness of mesopore structure was estimated by X-ray diffraction, N2 adsorption, and TEM analysis. The effects of the amount of HCl, TEOS and BuOH on the structure of KIT-6 were discussed. The time and temperature for the synthesis of KIT-6 were also optimized. The amount of vanadium content influenced the framework structure and crystallinity of the Ia3d phase significantly.

An attempt has been made to synthesize ceramic titania and zirconia membranes by sol-gel process by filtering respective viscous colloidal sol through microporous alumina support and gelling followed by sintering at 400°C and 470°C respectively. The static charge on the pores of the so formed membranes and the pore size distribution determine the applicability in filtering colloidal solution. The mean pore size from SEM were found to be 0.65 μm and 0.54 μm for titania and zirconia membranes respectively with 1.47 × 107/cm2 as pore density for both. The filtration characteristics during membrane layer formation showed that the membrane layer formation started after 35 minutes in the case of titania membrane and 40 minutes in the case of zirconia membrane. From the gravimetric estimation of water content of the membranes the thickness of the membrane was found out to be 3 μm and the porosity was found out to be 0.30 for both the cases. The particle charge density was estimated from the zeta potential and the particle size. The pore charge density was estimated from the particle charge density, pore density, pore diameter and the thickness of the membrane layer. The membrane pore charge density was found to vary between 3 to −1 μ Coulombs/cm2 in the case of titania membrane and 7 to −0.5 μ Coulombs/cm2 in the case of zirconia membrane in the pH range 1–12.