Efficient Zinc Vanadate Homojunction with Cadmium Nanostructures for Photocatalytic Water Splitting and Hydrogen Evolution.

Construction of a homojunction is an effective strategy for effective charge transfer to suppress charge carrier recombination in augmented photocatalysis. The present work reveals the synthesis of homojunction formation through the reinforcement of Cd nanostructures into a solid lattice of zinc vanadate (Zn3V2O8, ZnV) using the hydrothermal method. The formation of a homojunction between cadmium vanadate (CdV, Cd3V2O8) and ZnV was confirmed by various spectroscopic and electron microscopic techniques such as Fourier-transform infrared (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM) associated with energy-dispersive X-ray (EDX) mapping, transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and ultraviolet-visible spectrophotometry (UV-Vis). The synthesized material was explored for photocatalytic hydrogen (PC H2) production using the water splitting process under visible-light illumination. The spectroscopic and experimental results revealed that the formation of a CdV/ZnV homojunction significantly improved the transport of photogenerated charge carriers (electron-hole pairs) and thus resulted in enhanced H2 production efficiency (366.34 µmol g-1 h-1) as compared to pristine ZnV (229.09 µmol g-1 h-1) and CdV (274.91 µmol g-1 h-1) using methanol as a sacrificial reagent (SR) with water under visible-light illumination. The synergistic effect of Cd on ZnV NPs resulted in band gap reduction and broadened visible light absorption which was attributed to enhanced H2 production. The current study explains how a homojunction affects various features of important factors behind photocatalytic activity, which supports significant insights into the advancement of materials in the future.

Hydrothermal Synthesis of a Magnesium Vanadate-Functionalized Reduced Graphene Oxide Nanocomposite for an Efficient Photocatalytic Hydrogen Production.

Herein, we reported the fabrication of a magnesium vanadate-reduced graphene oxide (Mg3V2O8-rGO) composite. Further, the structural morphology of the as-prepared Mg3V2O8-rGO composite was studied by scanning electron microscopy. Powder X-ray diffraction and energy-dispersive X-ray spectroscopy techniques were also adopted to check the phase purity and elemental composition of the prepared Mg3V2O8-rGO composite. Mg3V2O8-rGO possesses a band gap of 2.98 eV, which prompted us to explore its photocatalytic activity for hydrogen (H2) evolution reaction. The Mg3V2O8-rGO composite demonstrated the generation of a reasonable amount of H2 evolution (97.45 µmol g-1), which is relatively higher than that of pristine Mg3V2O8 (17.45 µmol g-1). This may be attributed to the presence of synergism between Mg3V2O8 and rGO. In addition, Mg3V2O8-rGO also showed good stability and suggested its potential application for photocatalytic H2 evolution applications. So far, no report is available on the use of Mg3V2O8-rGO as a photocatalyst for H2 evolution. We propose the potential role of the Mg3V2O8-rGO composite for photocatalytic H2 evolution applications.

Self-Assembly of Copper Oxide Interfaced MnO2 for Oxygen Evolution Reaction.

Designing efficient electrocatalytic systems through facile synthesis remains a formidable task. To address this issue, this paper presents the design of a combination material comprising two transition metal oxides (copper oxide and manganese oxide (CuO/MnO2)), synthesized using a conventional microwave technique to efficiently engage as an active oxygen evolution reaction (OER) catalyst. The structural and morphological properties of the composite were confirmed by the aid of X-ray diffraction (XRD) studies, field emission scanning electron microscopy (FESEM), X-ray photoelectron spectroscopy (XPS), and energy-dispersive spectrometry (EDS). FESEM clearly indicated well-aligned interlacing of CuO with MnO2. The OER performance was carried out in 1 M KOH. The assembled CuO/MnO2 delivered a benchmark current density (j = 10 mA cm-2) at a minimal overpotential (η = 294 mV), while pristine CuO required a high η (316 mV). Additionally, the CuO/MnO2 electrocatalyst exhibited stability for more than 15 h. These enhanced electrochemical performances were attributed to the large volume and expanded diameter of the pores, which offer ample surface area for catalytic reactions to boost OER. Furthermore, the rate kinetics of the OER are favored in composite due to low Tafel slope (77 mV/dec) compared to CuO (80 mV/dec).

Synthesis and characterization of Hyaluronic Acid (HA) modified polymeric composite for effective treatment of wound healing by transdermal drug delivery system (TDDS).

The present study aimed to fabricate a novel polymeric spongy composite to enhance skin regeneration composed of Nystatin (antifungal agent) and Silver Nanoparticles (AgNps). Different formulations (F1-F8) were developed & characterized by using various analytical techniques. AgNps synthesized by chemical reduction method showed spherical morphology 2 µm in size showed by SEM and XRD. A fine porous structure of gel embedded with AgNps having an amorphous structure with 10 % crystallinity due to AgNps was found. IR spectra revealed no chemical interaction between polymers and Nystatin. An increase in thermal stability of formulation was observed till 700 â„ƒ analyzed by Differential Scanning Calorimetry. Cytotoxic analysis on L929 mouse skin fibroblast cells showed a decrease in cell viability as Ag concentration increased (inactivating Fibroblast and keratinocytes) while 10 mg composition was found safest concentration (94%). Optimized formulation (F2) presented in-vitro drug release up to 90.59% ± 0.76 at pH 7.4, swelling studies (87.5% ± 0.57), water retention (26.60 ± 0.34), pH (5.31 ± 0.03). In the animal burn model, the group that received CHG/Ag/Nystatin healed the wound significantly (p < 0.05). These results suggested that optimized carrier can be used for other anti-fungal drugs facilitating the early healing of the wound.

Efficient light-driven hydrogen evolution and azo dye degradation over the GdVO4@g-C3N4 heterostructure.

A straightforward hydrothermal technique was used for the synthesis of a g-C3N4/GdVO4 (CN/GdV) heterostructure as an alternate material for energy and environmental applications. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS) were used to characterize the synthesized g-C3N4 (CN), GdVO4 (GdV), and the CN/GdV heterostructure. The characterization results revealed the distribution of GdV over CN sheets. The as-fabricated materials were tested for their capacity to evolve hydrogen gas and degrade two azo dyes (Amaranth; AMR and Reactive Red2; RR2) in the presence of visible light. When compared to pure CN and GdV, the efficiency of CN/GdV toward hydrogen evolution was high, with H2 evolution of 8234, 10 838, and 16 234 µmol g-1 in 4 h, respectively. The CN/GdV heterostructure was able to degrade 96% and 93% of AMR (60 min) and RR2 (80 min), respectively. The enhanced activity with CN/GdV could be attributed to the type-II heterostructure and decreased recombination of charge carriers. The intermediate analysis of AMR and RR2 degradation was conducted using mass spectrometry (MS). The mechanism of photocatalysis was investigated and is discussed based on the optical and electrochemical characterizations. The efficient photocatalytic characteristics of CN/GdV could promote further research on metal vanadate nanocomposite materials.

An efficient and magnetically recoverable g-C3N4/ZnS/CoFe2O4 nanocomposite for sustainable photodegradation of organic dye under UV-visible light illumination.

Effective improvement of an easily recoverable photocatalyst is equally vital to its photocatalytic performance from a practical application view. The magnetically recoverable process is one of the easiest ways, provided the photocatalyst is magnetically strong enough to respond to an external magnetic field. Herein, we prepared graphitic carbon nitride nanosheet (g-C3N4), and ZnS quantum dots (QDs) supported ferromagnetic CoFe2O4 nanoparticles (NPs) as the gC3N4/ZnS/CoFe2O4 nanohybrid photocatalyst by a wet-impregnation method. The loading of CoFe2O4 NPs in the g-C3N4/ZnS nanohybrid resulted in extended visible light absorption. The ferromagnetic g-C3N4/ZnS/CoFe2O4 nanohybrid exhibited better visible-light-active photocatalytic performance (97.11%) against methylene blue (MB) dye, and it was easily separable from the aqueous solution by an external bar magnet. The g-C3N4/ZnS/CoFe2O4 nanohybrid displayed excellent photostability and reusability after five consecutive cycles. The favourable band alignment and availability of a large number of active sites affected the better charge separation and enhanced photocatalytic response. The role of active species involved in the degradation of MB dye during photocatalyst by g-C3N4/ZnS/CoFe2O4 nanohybrid was also investigated. Overall, this study provides a facile method for design eco-friendly and promising g-C3N4/ZnS/CoFe2O4 nanohybrid photocatalyst as applicable in the eco-friendly dye degradation process.

Metal organic frameworks enhanced dispersive solid phase microextraction of malathion before detection by UHPLC-MS/MS.

Metal organic frameworks are considered as an efficient and promised adsorbent for separation of several ions and compounds from solutions due to its unique geometric structure. Herein, copper-benzyl tricarboxylic acid based metal organic frameworks have showed a high efficiency in enrichment and microextraction of malathion from food and water samples. The microextraction procedures were followed by determination of malathion by ultra high performance liquid chromatography with tandem mass spectrometry. The optimum recoveries for malathion were obtained at pH 6, and with using 2 mL of ethyl acetate as the eluent. The microextraction procedures showed a detection limits and the quantification limits of 4.0 and 10.0 µg/L, respectively. The intra- and interday precision showed a relative standard deviation% less than 10. The feasibility of the proposed procedure was determined by evaluating the addition/recovery studies of malathion from the real samples. The absolute recovery% was ≥92%. Furthermore, some ions were tested as cointerfering ions, and the recovery% was 93-100%. These results confirm that the developed microextraction procedure based on copper-benzyl tricarboxylic acid based metal organic frameworks as extractor for dispersive solid phase microextraction is matrix-independent, and can be applied for various real samples including different matrix or various malathion content.

Phosphonium-based Ionic Liquid Modified Activated Carbon from Mixed Recyclable Waste for Mercury(II) Uptake.

The contamination of water surfaces by mercury is a dangerous environmental problem due to its toxicity, which leads kidney damage. Activated carbon from mixed recyclable waste modified by phosphonium-based ionic liquid (IL-ACMRW) was therefore prepared and evaluated for Hg(II) remediation. The activated carbon used in this study was prepared from mixed waste, including cardboard, papers and palm wastes as cheap raw materials. The mixed Recyclable Waste Activated Carbon was combined with trihexyl(tetradecyl)phosphonium Bis2,4,4-(trimethylpentyl)phosphinate (Cyphos® IL 104) ionic liquid to form an adsorbent with organic-inorganic content, in order to improve the Hg(II) uptake from aqueous solutions. FTIR confirms the presence of P, C=O and OH after this modification. The adsorption process was investigated and the evaluated results showed that the capacity was 124 mg/g at pH 4, with a contact time of 90 min, an adsorbent dose of 0.4 g/L, and a Hg(II) concentration of 50 mg/L. This Hg(II) adsorption capacity is superior than that reported in the literature for modified multiwall carbon nanotubes. The adsorption of Hg(II) on the modified activated carbon from mixed recyclable waste was found to follow the pseudo second-order kinetics model. Isotherms of adsorption were analyzed via Freundlich and Langmuir models. The results indicated that Freundlich is the best model to describe the process, suggesting multilayer adsorption.

Spectral, coordination and thermal properties of 5-arylidene thiobarbituric acids.

Synthesis of 5-arylidine thiobarbituric acids containing different functional groups with variable electronic characters were described and their Co(2+), Ni(2+) and Cu(2+) complexes. The stereochemistry and mode of bonding of 5-(substituted benzylidine)-2-TBA complexes were achieved based on elemental analysis, spectral (UV-VIS, IR, (1)H NMR, MS), magnetic susceptibility and conductivity measurements. The ligands were of bidentate and tridentate bonding through S, N and O of pyrimidine nucleolus. All complexes were of octahedral configuration. The thermal data of the complexes pointed to their stability. The mechanism of the thermal decomposition is discussed. The thermodynamic parameters of the dissociation steps were evaluated and discussed.

Spectral properties of some metal complexes derived from uracil-thiouracil and citrazinic acid compounds.

The reaction of FeCl(3) with uracil (H(2)L(1)), citrazinic acid (H(2)L(6)), 5-(phenylazo)citrazinic acid (H(2)L(7)), 5-(m-hydroxyphenylazo)citrazinic acid (H(2)L(8)) and 5-(m-nitrophenylazo)citrazinic acid (H(2)L(9)) leads to the formation of complexes with the empirical formula Fe(HL)(3).nH(2)O (n=1-3). All of the prepared complexes have octahedral complexation geometry where the azo group is not the reactive site for complexation. Thiouracil (H(2)L(2)) and the 5-(substituted phenylazo)thiouracil (H(2)L(3)-H(2)L(5)) ligands are bidentates on complexation with Co(II), Ni(II) and Cu(II). The complexes have been characterized by elemental analyses, IR, electronic spectra, magnetic susceptibility, DTA, electron spin resonance (copper complexes) and Mössbauer spectra (iron complexes). The coordination bond lengths between the metal ion and the active centers for complexation were calculated.