Efficiency and mechanistic insights of photocatalytic decomposition of tetracycline and rhodamine B utilizing Z-scheme g-C3N4/SnWO4 heterostructures under visible light irradiation.

The hydrothermal approach was used in the design and construction of the SnWO4 (SW) nanoplates anchored g-C3N4 (gCN) nanosheet heterostructures. Morphology, optical characteristics, and phase identification were investigated. The heterostructure architect construction and successful interface interaction were validated by the physicochemical characteristics. The test materials were used as a photocatalyst in the presence of visible light to break down the antibiotic tetracycline (TC) and the organic Rhodamine B (RhB). The best photocatalytic degradation efficiency of TC (97%) and RhB (98%) pollutants was demonstrated by the optimized 15 mg of gCNSW-7.5 in 72 and 48 min, respectively, at higher rate constants of 0.0409 and 0.0772 min-1. The interface contact between gCN and SW, which successfully enhanced charge transfer and restricted recombination rate in the photocatalyst, is responsible for the enhanced performance of the gCNSW heterostructure photocatalyst. In addition, the gCNSW heterostructure photocatalyst demonstrated exceptional stability and reusability over the course of four successive testing cycles, highlighting its durable and dependable function. Superoxide radicals and holes were shown to be key players in the degradation of contaminants through scavenger studies. The charge transfer mechanism in the heterostructure is identified as Z-scheme mode with the help of UV-vis DRS analysis. Attributed to its unique structural features, and effective separation of charge carriers, the Z-scheme gCNSW-7.5 heterostructure photocatalyst exhibits significant promise as an exceptionally efficient catalyst for the degradation of pollutants. This positions it as a prospective material with considerable potential across various environmental applications.

Advancements in Nickel-Phosphate/Boron Based Electroless Composite Coatings: A Comprehensive Review of Mechanical Properties and Recent Developments.

Nickel-Phosphate/Boron (Ni-P/B) electroless coatings have been widely used to improve physical and mechanical properties in various industrial applications, including the automotive, aerospace, chemical processing, food, oil and gas, electronic, textile, and printing industries. Electroless nickel coatings are one of the most popular surface-coating methods due to their low cost and short processing time. The purpose of this review is to look at several coating materials and the existing processes for making electroless coatings on different materials. The improvement of Ni-P/B composite coatings by the incorporation of secondary particles into an alloy matrix at the macro, micro, and nano levels is explained in detail. Process parameters like type of surfactant, annealing temperature, size of the reinforcement material, and reducing-agent percentage on mechanical characteristics like hardness, high-temperature oxidation behaviour, friction, coefficient, wear, and corrosion have been broadly researched and illustrated clearly.

Review of Recent Developments in the Fabrication of ZnO/CdS Heterostructure Photocatalysts for Degradation of Organic Pollutants and Hydrogen Production.

Researchers have recently paid a lot of attention to semiconductor photocatalysts, especially ZnO-based heterostructures. Due to its availability, robustness, and biocompatibility, ZnO is a widely researched material in the fields of photocatalysis and energy storage. It is also environmentally beneficial. However, the wide bandgap energy and quick recombination of the photoinduced electron-hole pairs of ZnO limit its practical utility. To address these issues, many techniques have been used, such as the doping of metal ions and the creation of binary or ternary composites. Recent studies showed that ZnO/CdS heterostructures outperformed bare ZnO and CdS nanostructures in terms of photocatalytic performance when exposed to visible light. This review largely concentrated on the ZnO/CdS heterostructure production process and its possible applications including the degradation of organic pollutants and hydrogen evaluation. The importance of synthesis techniques such as bandgap engineering and controlled morphology was highlighted. In addition, the prospective uses of ZnO/CdS heterostructures in the realm of photocatalysis and the conceivable photodegradation mechanism were examined. Lastly, ZnO/CdS heterostructures' challenges and prospects for the future have been discussed.

Ultra-fast photocatalytic degradation and seed germination of band gap tunable nickel doping ceria nanoparticles.

Doping transition metal ions into cerium oxide (CeO2) results in interesting modifications to the material, including an increase in surface area, a high isoelectric point, biocompatibility, greater ionic conductivity, and catalytic activity. Herein, various concentrations (1-5%, 10% and 20%) of nickel (Ni) doped CeO2 nanoparticle have been made by a facile chemical process. Using a variety of cutting-edge analytical techniques, the structural, optical, and photocatalytic properties of undoped and varied concentrations (1-5%, 10%, and 20%) of Ni doped CeO2 nanoparticles have been investigated. Pure cubic fluorite structure with average crystallite sizes in the region of 12-15 nm was determined by X-ray diffraction (XRD) investigation. Transmission electron microscopy (TEM), which revealed highly homogeneous hexagonal shape of the particles with average size of 15 nm, was also used to determine microstructural information. According to the optical absorption, the band gaps of Ni doped and undoped CeO2 nanoparticles were found to be 2.96 eV and 1.95 eV, respectively. When exposed to sunlight, the narrow band gap Ni doped CeO2 nanoparticles worked as an active visible light catalyst to remove the dyes Rose Bengal (RB) and Direct Yellow (DY). The best photodegradation efficiencies for RB and DY dyes were found about 93% and 97%, respectively, using the 5% Ni-doped CeO2 catalyst. The apparent rate constant values of 0.039 for RB and 0.040 min-1 were attained for DY. As well, the treated, untreated dye solution and control solutions were utilized to assess the toxicity of commercially accessible Vigna Radiata seeds. In this study exhibits percentages of length and germination increased by 30-35% when compared to dye pollutant solution. The Ni doped CeO2 can provide a substantial alternative for current industrial waste management because of its quick photocatalytic activity and remarkable seed germination results.

InVO4 nanosheets decorated with ZnWO4 nanorods: A novel composite and its enhanced photocatalytic performance under solar light.

InVO4 is the most attractive inorganic new-generation material for advanced scientific research, especially in the fields of energy and environmental science. In theory, this stable, non-toxic, energy-efficient metal vanadate semiconductor is expected to exhibit significant catalytic activity owing to its narrow bandgap energy. However, this has not been achieved in practice because of its inherent defects in terms of the separation and migration of charge carriers. In fact, the exploration of this material is still in its infancy, and more research is needed to improve its efficiency and speed up its commercialization. Band gap engineering using heterojunction formation offers better results than other methods, such as morphological variations and doping efforts. In this context, the present study offers a significant solution substantiated by experimental results. This includes the successful synthesis of a novel nanocomposite of InVO4 nanosheets decorated with ZnWO4 nanorods with a unique improved light absorption ability. Three composites with 26.48-33.85 nm crystal sizes and 11.74-19.98 m2/g surface area were prepared with tailor-made bandgap energies in the range of 2.52-2.97 eV. Furthermore, they produced high photoexcitation currents with low EIS resistance with respect to their constituents. The as-prepared InVO4-based novel catalyst almost completely (98.33%) decomposed tetracycline (TC) antibiotic in just 90 min, proving its high efficacy. The enhanced performance of the novel catalyst is 7.6 times that of InVO4 and 10 times that of ZnWO4. Moreover, the catalyst intake was significantly small (15 mg/100 mL TC solution).

Noble metals (Pd, Ag, Pt, and Au) doped bismuth oxybromide photocatalysts for improved visible light-driven catalytic activity for the degradation of phenol.

The doping of noble metals onto the semiconductor metal oxides has a great impact on the intrinsic properties of the materials. This present work reports the synthesis of noble metals doped BiOBr microsphere by a solvothermal method. The various characteristic findings reveal the effective incorporation of Pd, Ag, Pt, and Au onto the BiOBr and the performance of synthesized samples was test for the degradation of phenol over visible light. The Pd-doped BiOBr material showed enhanced phenol degradation efficacy, which is ∼4-fold greater than pure BiOBr. This improved activity was on reason of good photon absorption, lower recombination rate, and higher surface area facilitated by surface plasmon resonance. Moreover, Pd-doped BiOBr sample displayed good reusability and stability after 3 cycles of run. A plausible charge transfer mechanism for phenol degradation is disclosed in detail over Pd-doped BiOBr sample. Our findings disclose that the incorporation of noble metal as the electron trap is a feasible approach to enhance visible light activity of BiOBr photocatalyst used in phenol degradation. This work represents new vision interested in the outline and development of noble metal doped semiconductor metal oxides as a visible light material for the elimination of colorless toxins from untreated wastewater.

Fabrication of InVO4/SnWO4 heterostructured photocatalyst for efficient photocatalytic degradation of tetracycline under visible light.

In the present study, novel InVO4/SnWO4 nanocomposites with different concentrations of SnWO4 were successfully prepared using a facile hydrothermal technique and investigated employing a wide range of analytical methods for efficient photocatalytic degradation of tetracycline (TC). X-ray diffraction analysis showed the presence of the orthorhombic phases of both InVO4 and SnWO4 in the composite catalyst. Dispersion of SnWO4 nanoplates over the InVO4 nanosheets enhanced the synergistic interactions, improving the separation of charge carriers and their transfer. Furthermore, the formation of heterostructure expanded the absorption range and promoted visible light harvesting. The TC degradation efficiency of InVO4/SnWO4 nanocomposite (5 mg loading of SnWO4) reached 97.13% in 80 min under visible light, with the kinetic rate constants 5.51 and 7.63 times greater than those of pure InVO4 and SnWO4, respectively. Additionally, the scavenger results proved that hydroxyl radicals and holes played a significant role in the photodegradation of TC. Furthermore, the electrochemical impedance spectroscopy (EIS) and transient photocurrent response analysis showed enhanced e-/h+ partition efficiency. Thus, the formation of heterostructure with strong synergistic interactions can effectively transfer the excited charge carriers and shorten the reunion rate. Accordingly, the InVO4/SnWO4 nanocomposites exhibited remarkable photocatalytic performance due to the increased number of charge carriers on the surface.

2D MXene Nanomaterials as Electrocatalysts for Hydrogen Evolution Reaction (HER): A Review.

MXenes, a novel family of 2D transition metal carbide, nitride and carbonitride materials, have been gaining tremendous interest in recent days as potential electrocatalysts for various electrochemical reactions, including hydrogen evolution reaction (HER). MXenes are characterized by their etchable metal layers, excellent structural stability, versatility for heteroatoms doping, excellent electronic conductivity, unique surface functional groups and admirable surface area, suitable for the role of electrocatalyst/support in electrochemical reactions, such as HER. In this review article, we summarized recent developments in MXene-based electrocatalysts synthesis and HER performance in terms of the theoretical and experimental point of view. We systematically evaluated the superiority of the MXene-based catalysts over traditional Pt/C catalysts in terms of HER kinetics, Tafel slope, overpotential and stability, both in acidic and alkaline electrolytic environments. We also pointed out the motives behind the electro catalytic enhancements, the effect of synthesis conditions, heteroatom doping, the effect of surface terminations on the electrocatalytic active sites of various MXenes families. At the end, various possible approaches were recommended for a deeper understanding of the active sites and catalytic improvement of MXenes catalysts for HER.

Novel BiVO4-nanosheet-supported MoS2-nanoflake-heterostructure with synergistic enhanced photocatalytic removal of tetracycline under visible light irradiation.

This paper describes a simple in-situ hydrothermal technique for the production of BiVO4/MoS2 binary nanocomposites as visible-light-driven catalysts. The as-prepared samples were analyzed by structural, morphological, compositional, optical, surface area, and photocurrent analyses. The lattice fringe spaces at 0.304 nm and 0.612 nm were indexed to the (112) and (002) crystal planes of BiVO4 and MoS2, respectively. Antibacterial photocatalytic capabilities were assessed using tetracycline (TC). Consequently, it was observed that the BiVO4/MoS2 nanocomposite demonstrated improved antibacterial removal ability compared with the pristine samples. The BiVO4/MoS2 nanocomposite exhibited 97.46% removal of TC compared with the pure BiVO4 (43.76%) and MoS2 (35.28%) samples within 90 min. Thus, the photocatalytic performance was observed to follow the given order: BiVO4/MoS2 nanocomposite > BiVO4 > MoS2. The removal of TC after 90 min of irradiation was approximately 97.46%, 96.62%, 95.59%, and 94.45% after the 1st, 2nd, 3rd, and 4th cycles, respectively. Thus, the recycling tests revealed the stability of the photocatalyst, which exhibited a TC removal efficiency of 94.45% without distinct decay, even after the 4th cycle. According to the trapping results, hydroxyl radicals and holes were the key species and demonstrated a greater influence on the photocatalytic performance than superoxide radicals. The increased activity of the BiVO4/MoS2 nanocomposite may be attributed to its large surface area and tunable bandgap, which accelerate the charge-transport characteristics of the photocatalytic system. This insight and synergetic effects can provide a new approach for the development of novel heterostructure photocatalysts.

Visible-light-driven indium vanadium oxide nanosheets supported bismuth tungsten oxide nanoflakes heterostructure as an efficient photocatalyst for the tetracycline degradation.

The development of excellent photocatalysts is of great significance for the efficient photocatalytic degradation process, however, the low carrier separation efficiency and poor light absorption ability typically limit the performance of photocatalysts. Herein, a visible light responsive heterostructure composed with indium vanadium oxide nanosheets supported bismuth tungsten oxide nanoflakes (InVO4/Bi2WO6) was synthetized through in-situ hydrothermal method. Further, the photocatalytic activity was performed for tetracycline (TC) under visible light illumination. The InVO4/Bi2WO6 heterostructure builds a strong interface between InVO4 and Bi2WO6 to hinder reunion of photoinduced charge carriers, and provides the sensitive agents for the removal of TC. In particular, the InVO4/Bi2WO6 photocatalyst prepared by taking 5.0 mg of Bi2WO6 shows the highest degradation of TC about 97.42% in 72 min. The quenching experiments identified that hydroxyl radicals, and holes dominated in the photocatalytic process. Furthermore, the optimized nanocomposite is stable even after four cycles, which exposes the excellent photostability and reusability of the photocatalyst. In addition, a plausible degradation pathway and mechanism of TC over InVO4/Bi2WO6 nanocomposite is also projected.

Novel Z-scheme binary zinc tungsten oxide/nickel ferrite nanohybrids for photocatalytic reduction of chromium (Cr (VI)), photoelectrochemical water splitting and degradation of toxic organic pollutants.

A simple hydrothermal approach was demonstrated for synthesizing a coupled NiFe2O4-ZnWO4 nanocomposite, wherein one-dimensional ZnWO4 nanorods were inserted into two-dimensional NiFe2O4 nanoplates. Herein, we evaluated the photocatalytic removal of Cr(VI), and degradation of tetracycline (TC) and methylene blue (MB) by the nanocomposite, as well as its ability to split water. The ZnWO4 nanorods enriched the synergistic interactions, upgraded the solar light fascination proficiency, and demonstrated outstanding detachment and migration of the photogenerated charges, as confirmed by a transient photocurrent study and electrochemical impedance spectroscopy measurements. Compared to pristine NiFe2O4 and ZnWO4, the NiFe2O4-ZnWO4 nanocomposite exhibited a higher Cr(VI) reduction (93.5%) and removal of TC (97.9%) and MB (99.6%). Radical trapping results suggested that hydroxyl and superoxide species are dominant reactive species, thereby facilitating the Z-scheme mechanism. Furthermore, a probable photocatalytic mechanism was projected based on the experimental results. The photoelectrochemical analysis confirmed that NiFe2O4-ZnWO4 exhibited minor charge-transfer resistance and large photocurrents. We propose a novel and efficient approach for designing a coupled heterostructured nanocomposites with a significant solar light ability for ecological conservation and water splitting.

An effective CuO/Bi2WO6 heterostructured photocatalyst: Analyzing a charge-transfer mechanism for the enhanced visible-light-driven photocatalytic degradation of tetracycline and organic pollutants.

Over the past few years, industrial pollution has had a negative impact on aquatic life by releasing significant amounts of hazardous chemicals into the ecosystem. Therefore, it is imperative to develop photocatalytic materials with good photocatalytic activity and easy separation. Photocatalytic degradation has been employed for the removal of such contaminants using binary hybrid nanocomposites as photocatalysts. In the present study, binary CuO/Bi2WO6 (CuBW) nanocomposites with different loadings of Bi2WO6 (~5, 10, and 15 mg) were successfully constructed using a simple hydrothermal method and used as a potential photocatalyst for the degradation of tetracycline (TC) and methylene blue (MB) under visible-light irradiation. The structure, surface morphology, and optical properties were studied to investigate the formation of the heterostructure. Among the prepared samples, the CuBW nanocomposite containing the optimum content of Bi2WO6 (~10 mg) exhibited superior activity toward the photocatalytic degradation of TC (97.72%) in 75 min and MB (99.43%) in 45 min under visible-light illumination. Radical trapping experiments suggested that holes and •OH radicals were the dominant reactive species during the photocatalytic process. The photoelectrochemical results also confirmed the improved separation and transfer of electron-hole pairs at the interface of Bi2WO6 and CuO. Our results demonstrate that the binary CuO/Bi2WO6 nanocomposite has significant potential applications in the field of photocatalysis due to its enhanced separation of the photoexcited charge carriers and strong synergistic interactions.

Enhanced solar-light-driven photocatalytic properties of novel Z-scheme binary BiPO4 nanorods anchored onto NiFe2O4 nanoplates: Efficient removal of toxic organic pollutants.

Global environmental problems have been increasing with the growth of the world economy and have become a crucial issue. To replace fossil fuels, sustainable and eco-friendly catalysts are required for the removal of organic pollutants. In this study, nickel ferrite (NiFe2O4) was prepared using a simple wet-chemical synthesis, followed by calcination; bismuth phosphate (BiPO4) was also prepared using a hydrothermal method. Further, NiFe2O4/BiPO4 nanocomposites were prepared using a hydrothermal technique. Numerous characterization studies, such as structural, morphology, surface area, optical, photoluminescence, and photoelectrochemical investigations, were used to analyze NiFe2O4/BiPO4 nanocomposites. The morphology analysis indicated a successful decoration of BiPO4 nanorods on the surface of NiFe2O4 nanoplate. Further, the bandgap of the NiFe2O4/BiPO4 nanocomposites was modified owing to the formation of a heterostructure. The as-prepared NiFe2O4/BiPO4 nanocomposite exhibited promising properties to be used as a novel heterostructure for tetracycline (TC) and Rhodamine B (RhB) removal. The NiFe2O4/BiPO4 nanocomposite degrades TC (98%) and RhB (99%) pollutants upon solar-light irradiation within 100 and 60 min, respectively. Moreover, the trapping experiments confirmed the Z-scheme approach of the prepared nanocomposites. The efficient separation and transfer of photogenerated electron-hole pairs rendered by the heterostructure were confirmed by utilizing electrochemical impedance spectroscopy, photocurrent experiments, and photoluminescence. Mott-Schottky measurements were used determine the positions of the conduction and valence bands of the samples, and the detailed mechanism of photocatalytic degradation of toxic pollutants was projected and discussed.

Recent progress in transition metal oxide/sulfide quantum dots-based nanocomposites for the removal of toxic organic pollutants.

Water is an essential solvent that is extremely necessary for the survival of life. Water pollution due to the increased utilization of water for various processes, including domestic and industrial activities, poses a special threat that contaminates both surface and ground water. In recent years, advanced oxidation processes (AOPs) have been applied to deal with wastewater problems, which is a green method used to oxidize organic contaminants with strong oxidative radical species. Among the AOPs, photocatalytic technology is one of the most promising strategies for wastewater cleaning, which fulfills the aims of environmentally friendly and sustainable development. Owing to their unique electronic, optical, and structural properties, nanoscale semiconductors have received substantial interest as materials for AOPs, particularly inspired by their superb quantum confinement effects and large surface-area-to-volume ratio, which are essential for catalytic reaction kinetics. Recent advancements have revealed that semiconductor nanocrystals, known as quantum dots (QDs), are newly emerging zero-dimensional (0-D) nanomaterials, which have garnered much attention owing to their special physiochemical characteristics such as high conductivity, thermo-chemical and opto-mechanical stability, high adsorption coefficients, and, most importantly, their admirable recyclability. In this review, we provide a clear understanding of the importance of semiconductor QD-based nanocomposites in the degradation of organic pollutants, in addition to the mechanism involved in the reaction process. Following this, the enhancement of different materials, such as metal oxides and metal sulfide QD-based nanocomposites, is discussed in the context of combating environmental pollution.

Enhanced solar-light-driven photocatalytic and photoelectrochemical properties of zinc tungsten oxide nanorods anchored on bismuth tungsten oxide nanoflakes.

At present, sustainable water supply and energy generation are the most important challenges faced by humankind globally. Thus, it is crucial to progress ecological techniques for sustainable removal of organic pollutants from wastewater and generation of hydrogen as an alternative to fossil fuels. In this study, zinc tungsten oxide (ZnWO4) nanorods, bismuth tungsten oxide (Bi2WO6) nanoflakes, and Bi2WO6/ZnWO4 (BO-ZO) nanocomposites were prepared via a simple hydrothermal approach. X-ray diffraction, scanning electron microscopy, transmission electron microscopy, high-resolution transmission electron microscopy, diffuse reflectance spectroscopy, and electrochemical analyses were conducted to confirm the formation of the BO-ZO heterostructure. The structural and morphological analyses revealed that the ZnWO4 nanorods were moderately dispersed on the Bi2WO6 nanoflakes. The bandgap tuning of BO-ZO nanocomposite confirmed the establishment of the heterostructure with band bending properties. The BO-ZO nanocomposite could degrade 99.52% of methylene blue (MB) within 60 min upon solar-light illumination. The photoelectrochemical (PEC) measurement results showed that the BO-ZO nanocomposite showed low charge-transfer resistance and high photocurrent response with good stability. The BO-ZO photoanode showed a low charge-transfer resistance of 35.33 Ω and high photocurrent density of 0.1779 mA/cm2 in comparison with Ag/AgCl in a 0.1 M Na2SO3 electrolyte under solar-light illumination. The MB photocatalytic degradation and PEC water oxidation mechanisms of the nanocomposite were investigated.

Plasmonic ZnO/Au/g-C3N4 nanocomposites as solar light active photocatalysts for degradation of organic contaminants in wastewater.

In the present study, novel ZnO/Au/graphitic carbon nitride (g-C3N4) nanocomposites were fabricated via a facile and eco-friendly liquid phase pulsed laser process followed by calcination. Notably, the approach did not necessitate the use of any capping agents or surfactants. The as-prepared photocatalysts were evaluated by various electron microscopy and spectroscopy techniques. The obtained results confirmed good dispersion of the Au nanoparticles (NPs) on the surface of spherical ZnO particles deposited on the g-C3N4 nanosheets. The ZnO/Au/g-C3N4 nanocomposite exhibited substantially enhanced catalytic activity toward the degradation of methylene blue (MB) under simulated solar light irradiation. In particular, the ZnO/Au15/g-C3N4 composite containing 15 wt% Au displayed a rate constant, which was approximately 3 and 5 times greater than those of pristine g-C3N4 and ZnO, respectively. This improved photocatalytic activity of ZnO/Au15/g-C3N4 was attributed to the surface plasmon resonance of Au NPs and the synergistic effects between ZnO and g-C3N4. The boundary between ZnO/Au and g-C3N4 enabled direct migration of the photogenerated electrons from g-C3N4 to ZnO/Au, which hindered the recombination of electron-hole pairs and enhanced the carrier separation efficiency. Additionally, a plausible MB degradation mechanism over the ZnO/Au/g-C3N4 photocatalyst is proposed based on the results of the conducted scavenger study.

Ultra-small zinc oxide nanosheets anchored onto sodium bismuth sulfide nanoribbons as solar-driven photocatalysts for removal of toxic pollutants and phtotoelectrocatalytic water oxidation.

Heterostructured nanohybrids were prepared from sodium bismuth sulfide (NaBiS2) and zinc oxide (ZnO) through hydrothermal process. The nanocomposite was used for tetracycline (TC) degradation as well as photoelectrochemical (PEC) water oxidation. Morphology and structural analyses were performed to confirm the dispersion of ultra-small ZnO nanosheets into the NaBiS2 nanoribbons. By tuning the band gap, it was possible to degrade tetracycline toxic pollutant within 90 min under the simulated solar light irradiation, while PEC suggested a lower charge-transfer resistance, high photocurrent response, and exceptionally good stability. The highest photocurrent density of 0.751 mAcm-2 vs. Ag/AgCl in 0.1 M Na2SO3 solution was observed under solar-light illumination. Detailed photocatalytic mechanisms for the degradation of TC and PEC water oxidation are discussed.

Z-scheme binary 1D ZnWO4 nanorods decorated 2D NiFe2O4 nanoplates as photocatalysts for high efficiency photocatalytic degradation of toxic organic pollutants from wastewater.

In this study, dimensionally coupled Z-scheme binary nanocomposites from two-dimensional (2D) NiFe2O4 nanoplates and one-dimensional (1D) ZnWO4 nanorods are prepared for efficient degradation of an antibiotic tetracycline (TC) and organic dye rhodamine B (RhB) under solar illumination. NiFe2O4/ZnWO4 nanocomposites were synthesized by a simple and ecological in-situ hydrothermal method without the use of surfactants. Structural and morphological studies revealed the formation of heterostructure and 1D ZnWO4 nanorods were uniformly distributed over the surface of NiFe2O4 nanoplates. Light-harvesting capability was improved and optimized by loading with different amounts of ZnWO4. Photoluminescence analysis demonstrated inhibited nature of the recombination of photo-excited charge carriers in the nanocomposites. Photocatalytic experiments revealed that the nanocomposite exhibited improved Z-scheme electron-transfer for the degradation of TC under solar illumination. In particular, NFZW-20 nanocomposite demonstrated superior photocatalytic degradation of TC of approximately 98% within 105 min. Furthermore, their photocatalytic performance was investigated by RhB dye under the solar irradiation to achieve 98% of degradation of RhB in 70 min. Improved photocatalytic activities are attributed to the Z-scheme electron-transfer mechanism, which could enhance the superior ability of light absorption and reduced recombination rate of the photogenerated charge carriers.

ZnO nanosheets-decorated Bi2WO6 nanolayers as efficient photocatalysts for the removal of toxic environmental pollutants and photoelectrochemical solar water oxidation.

Herein we report the fabrication of novel Bi2WO6/ZnO heterostructured hybrids for organic contaminant degradation from wastewater and photoelectrochemical (PEC) water splitting upon solar illumination. The Bi2WO6/ZnO photocatalysts were synthesized using a simple and eco-friendly hydrothermal process without the support of any surfactants. From the photocatalytic experiments, heterostructured Bi2WO6/ZnO nanohybrid catalysts exhibited considerably better photocatalytic performance for rhodamine B (RhB) degradation under solar illumination. The BWZ-20 nanocomposite demonstrated superior photodegradation of RhB dye up to 99% in about 50 min. Furthermore, BWZ-20 photoelectrode showeda lower charge-transfer resistance than other samples prepared, suggesting its suitability for PEC water splitting. The photocurrent densities of Bi2WO6/ZnO photoelectrodes were evaluated under the solar irradiation. The BWZ-20 photoelectrode exhibited a significant photocurrent density (0.45 × 10-3A/cm2) at +0.3 V vs. Ag/AgCl, which was~1036-times higher than that of pure Bi2WO6, and ~4.8-times greater than the pure ZnO. Such improved photocatalytic and PEC activities are mainly attributed to the formation of an interface between ZnO and Bi2WO6, superior light absorption ability, low charge-transfer resistance, remarkable production of charge carriers, easy migration of charges, and suppression of the recombination of photogenerated charge carriers.

Colorimetric Detection of UO2+2 Using Gold Nanoparticles Immobilized with Pillar[5]arene Complexes with Nitrophenyldiacetic Acids as a Chemoprobe.

Uranium is a crucial raw material in the nuclear energy industry; however, its radioactive nature makes it a critically damaging component to both the atmosphere and human health. In this study, we report a simple and cost-effective selective colorimetric detection technique for UO2+2 using nitrophenyldiacetic acids (NPD)-functionalized gold nanoparticles (Au NPs 1). The hybrid Au NPs 1 can be induced to aggregate in the presence of UO2+2 ions. UO2+2 can be recognized by the colorimetric response of hybrid Au NPs 1, which can be observed by a UV-Vis spectrophotometer and it is easily detectable by the naked eye. The hybrid Au NPs 1 bound by UO2+2 possess a good selective response compared to other metal ions (Li+, Na+, K+, Rb+, Cs+, Ca2+, Mg2+, Ba2+, Ni2+, Zn2+, and Co2+), which can be observed by a prominent color change. The color of the hybrid Au NPs 1 changed from red to dark red upon addition of UO2+2 in the presence of other metal ions. Job's plot demonstrates that one NPD moiety attached onto the surface of Au NPs 1 forms 1:1 stoichiometry with UO2+2, hence providing a simple and effective colorimetric sensor for the real-time detection of UO2+2.