Preparation of a New Polyaniline/CdO Nanocomposite and Investigation of Its Photocatalytic Activity: Comparative Study under UV Light and Natural Sunlight Irradiation

Two-dimensional porous porphyrin materials composed of robust tin(IV)-porphyrin linkages for photocatalytic wastewater remediation

Porphyrin-based two-dimensional porous materials (SnP-H2TCPP, SnP-ZnTCPP) composed of robust Sn(IV)-porphyrin linkages have been synthesized by reacting trans-dihydroxo[5,10,15,20-tetraphenylporphyrinato]tin(IV) (SnP) with [5,10,15,20-tetrakis(4-carboxyphenyl)porphyrin] (H2TCPP) and [5,10,15,20-tetrakis(4-carboxyphenyl)porphyrinato]zinc(II) (ZnTCPP), respectively. The strength of the interaction between the carboxylic acid group of the monomeric porphyrins (H2TCPP and ZnTCPP) and the axial hydroxyl moiety of SnP enables the construction of highly stable framework materials, which were characterized by FT-IR, UV-vis, and emmission spectroscopy, powder XRD, elemental analysis, and thermogravimetric analysis (TGA). SnP-H2TCPP and SnP-ZnTCPP absorb visible light strongly over a wide range, demonstrating weak perturbation in the electronic ground state structures of the π-conjugated aromatic moieties compared to the starting monomeric units. TGA indicated that SnP-H2TCPP and SnP-ZnTCPP exhibited greater thermal stability than SnP. The permanent porosity of SnP-H2TCPP and SnP-ZnTCPP resulted in large specific surface areas (BET) of 210.0 m2 g-1 and 185.0 m2 g-1, respectively. Uniform spherical nanoplates with an average diameter in the range of 900-1000 nm were observed for SnP-H2TCPP, whereas a nanocomposite morphology was observed for SnP-ZnTCPP, whose shape and size could not be specifically defined. Finally, the photodegradation performance of SnP-H2TCPP and SnP-ZnTCPP was found to be 89% (K = 0.0179 min-1) and 97% (K = 0.0246 min-1) within 120 min, respectively, for the degradation of methylene blue (MB), and 50% (K = 0.0091 min-1) and 60% (K = 0.0120 min-1) within 75 min, respectively, for the tetracycline (TC) antibiotic. The enhanced catalytic photodegradation activity of SnP-H2TCPP or SnP-ZnTCPP is attributed to the cooperation between the carboxylate-bearing porphyrin units and SnP.

Photocatalytic Degradation of Methylene Blue Dye using PANI-CuFe2O4 Nano Composite

The present perspective accentuates the synthesis of PANI-CuFe2O4 (PCF) nanocomposite, and photocatalytic degradation of methylene blue (MB) dye using a synthesized composite. The stable PCF is confirmed and characterized by analytical techniques, namely, fourier transform infrared (FTIR) and X-ray photoelectron (XPS) spectroscopy, X-ray diffraction (XRD), energy-dispersive X-ray (EDX), scanning electron microscopy (SEM), and vibrating sample magnetometry (VSM) analysis. The synthesized PCF nanocomposites are significantly crystalline in nature, having magnetic saturation of 10.47 emu g-1, and monoclinic crystalline structure as well as the size of nanocomposite is 39.54 nm verified by XRD pattern. SEM analysis revealed a regular porous and rough surface of nanocomposite. In addition, the nanocomposite divulged the remarkable efficient elimination of MB dye with maximum removal of 96% with good fitting of Langmuir isotherm, indication of monolayer formation on the catalyst surface through the interaction between nanocomposite and dye molecule. The adsorption kinetics bolstered the pseudo-second-order kinetic model, suggesting the adsorption process proceeded by chemisorption. The most notable feature of the nanocomposite is the reusability and good stability after several cycles, maintaining 90% after five cycles.

Development and Performance of a PANI@NiMnO3 Nanocomposite for Enhanced Supercapacitors and Photocatalytic Applications

Conductive polymers are gaining considerable attention as a potential material for supercapacitor electrodes due to their favorable properties. Among these, polyaniline (PANI) stands out as a cost-effective and easy to synthesize, making it a promising candidate for improving energy storage applications. This study presents the synthesis of a hybrid composite consisting of PANI and NiMnO3 (NMO) perovskite using the chemical oxidative polymerization method. The morphology and structure of the composite were analyzed by using scanning electron microscopy (SEM) and X-ray diffraction (XRD), respectively. XRD results showed that the addition of NMO transformed the amorphous structure of PANI into a semicrystalline form, leading to enhanced conductivity. SEM images revealed a more uniform and compact structure, with NMO distributed unevenly within the polymer matrix. Optical analysis indicated that a reduction in the band gap of PANI@NMO reached 2.5 eV. N2 adsorption-desorption measurements confirmed an increase in the surface area and pore volume. The photocatalytic activity of the PANI@NMO nanocomposite was tested by degrading methylene blue (MB) dye under UV/visible light. The nanocomposite showed high efficiency, degrading 87.75% of MB dye after 125 min of irradiation as compared to their counter parts. Additionally, electrochemical tests demonstrated an improved electrochemical performance of the composite due to enhanced crystallinity, increased surface area, and reduced electron-hole recombination rate. These results suggest that the PANI@NMO nanocomposite has great potential for use in supercapacitors and photocatalysis.

Experimental exploration and DFT analysis of the kinetics and mechanism of malachite green photodegradation catalyzed by polyaniline-copper oxide nanocomposite

CONTEXT AND RESULTS

A nanocomposite photocatalyst consisting of polyaniline (PANI) and copper oxide (CuO) was successfully synthesized through an in-situ polymerization approach using aniline as the precursor. The synthesized nanocomposite was characterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), UV-visible spectroscopy (UV-Vis), determination of the point of zero charge (pHPZC), and scanning electron microscopy (SEM). The photocatalytic efficiency of the PANI-CuO nanocomposite was evaluated in the context of photodegrading Malachite Green (MG) dye under visible light. Malachite Green, a synthetic dye commonly used in the textile and aquaculture industries, is a significant contaminant due to its toxic, mutagenic, and carcinogenic properties, making its removal from water resources crucial for environmental and human health. Distilled water artificially contaminated with MG dye was used as the medium for testing. The parameters influencing the photodegradation efficiency were comprehensively investigated. These parameters included catalyst dosage, reaction time, initial dye concentration, and pH. The results of this study indicate that the degradation efficiency of MG dye displayed an upward trend with time, catalyst dosage, and pH while exhibiting a converse relationship with the initial dye concentration. A degradation rate of 97% was achieved with an initial concentration of 20 mg L-1, employing a catalyst dose of 1.6 g L-1 at pH 6 for a reaction time of 180 min. Furthermore, the reusability of the catalyst was assessed, revealing consistent performance over five consecutive cycles.

COMPUTATIONAL AND THEORETICAL TECHNIQUES

Density functional theory (DFT) was employed to optimize the structures of PANI, PANI-CuO, and their respective complexes formed through dye interaction, employing Gaussian software. These calculations employed the B3LYP/6-311G +  + (d,p) basis set in an aqueous environment with water serving as the solvent. The kinetics of Malachite Green degradation were analyzed using both first and second-order kinetic models.

Sn(IV)porphyrin-Incorporated TiO2 Nanotubes for Visible Light-Active Photocatalysis

In this study, two distinct photocatalysts, namely tin(IV)porphyrin-sensitized titanium dioxide nanotubes (SnP-TNTs) and titanium dioxide nanofibers (TNFs), were synthesized and characterized using various spectroscopic techniques. SnP-TNTs were formed through the hydrothermal reaction of NaOH with TiO2 (P-25) nanospheres in the presence of Sn(IV)porphyrin (SnP), resulting in a transformation into Sn(IV)porphyrin-imbedded nanotubes. In contrast, under similar reaction conditions but in the absence of SnP, TiO2 (P-25) nanospheres evolved into nanofibers (TNFs). Comparative analysis revealed that SnP-TNTs exhibited a remarkable enhancement in the visible light photodegradation of model pollutants compared to SnP, TiO2 (P-25), or TNFs. The superior photodegradation activity of SnP-TNTs was primarily attributed to synergistic effects between TiO2 (P-25) and SnP, leading to altered conformational frameworks, increased surface area, enhanced thermo-chemical stability, unique morphology, and outstanding visible light photodegradation of cationic methylene blue dye (MB dye). With a rapid removal rate of 95% within 100 min (rate constant = 0.0277 min-1), SnP-TNTs demonstrated excellent dye degradation capacity, high reusability, and low catalyst loading, positioning them as more efficient than conventional catalysts. This report introduces a novel direction for porphyrin-incorporated catalytic systems, holding significance for future applications in environmental remediation.

Catalytic polymer nanocomposites for environmental remediation of wastewater

The removal of harmful chemicals and species from water, soil, and air is a major challenge in environmental remediation, and a wide range of materials have been studied in this regard. To identify the optimal material for particular applications, research is still ongoing. Polymer nanocomposites (PNCs), which combine the benefits of nanoparticles with polymers, an alternative to conventional materials, may open up new possibilities to overcome this difficulty. They have remarkable mechanical capabilities and compatibility due to their polymer matrix with a very high surface area to volume ratio brought about by their special physical and chemical properties, and the extremely reactive surfaces of the nanofillers. Composites also provide a viable answer to the separation and reuse problems that hinder nanoparticles in routine use. Understanding these PNCs materials in depth and using them in practical environmental applications is still in the early stages of development. The review article demonstrates a crisp introduction to the PNCs with their advantageous properties as a catalyst in environmental remediation. It also provides a comprehensive explanation of the design procedure and synthesis methods for fabricating PNCs and examines in depth the design methods, principles, and design techniques that guide proper design. Current developments in the use of polymer nanocomposites for the pollutant treatment using three commonly used catalytic processes (catalytic and redox degradation, electrocatalytic degradation, and biocatalytic degradation) are demonstrated in detail. Additionally, significant advances in research on the aforementioned catalytic process and the mechanism by which contaminants are degraded are also amply illustrated. Finally, there is a summary of the research challenges and future prospects of catalytic PNCs in environmental remediation.

Structural and optical properties of silver supported α-Fe2O3 nanocomposite fabricated by Saraca asoca leaf extract for the effective photo-degradation of cationic dye Azure B

In recent decades, several nanocomposites developed by chemical synthetic routes, have been demonstrated as efficient photocatalysts for the photodegradation of hazardous organic dyes. The present investigation reports the sonochemical-assisted fabrication of silver-supported α-Fe2O3 nanocomposites (SA@Ag@IONCs) using the Saraca asoca leaf extract. The magnetic nanocomposites can be easily removed from the reaction mixture. The morphology of these materials was characterized by field emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM), XPS, BET surface area analyzer, UV-visible spectroscopy, photoluminescence, X-ray diffraction (XRD), and VSM techniques. The XRD and electron microscopy analyses revealed the small size and well-crystalline SA@Ag@IONC particles with spherical and buckyball structures. The large surface area of SA@Ag@IONCs was confirmed by BET analysis. The absorption edge in UV-visible spectra appeared to migrate towards high wavelengths for the SA@Ag@IONC composite, causing a change in the bandgap energy. In the case of the sonication assisted composite, the bandgap energy was 2.1 eV, making it easier for the electron to transfer from the valence band to conduction band. The decoration of ultrasmall silver onto the surfaces of the α-Fe2O3 nanocomposite, which considerably increases the capacity to absorb sunlight, enhances the efficiency of charge carrier separation, and inhibits the electron-hole recombination rate as confirmed by the reduced PL intensity, is responsible for the excellent photocatalytic degradation performance. Outcomes shown SA@Ag@IONCs have a high photodegradation rate as well as high-rate constant value at an optimized condition that is at pH 9 and 0.5 g L-1 dose of nanocomposite, photodegradation rate of Azure B is ∼94%. Trap experiment results indicated that O2˙- and h+ are the active species responsible for the photodegradation of AzB.

Bismuth Vanadate Decked Polyaniline Polymeric Nanocomposites: The Robust Photocatalytic Destruction of Microbial and Chemical Toxicants

Functional materials have long been studied for a variety of environmental applications, resource rescue, and many other conceivable applications. The present study reports on the synthesis of bismuth vanadate (BiVO₄) integrated polyaniline (PANI) using the hydrothermal method. The topology of BiVO₄ decked PANI catalysts was investigated by SEM and TEM. XRD, EDX, FT-IR, and antibacterial testing were used to examine the physicochemical and antibacterial properties of the samples, respectively. Microscopic images revealed that BiVO₄@PANI are comprised of BiVO₄ hollow cages made up of nanobeads that are uniformly dispersed across PANI tubes. The PL results confirm that the composite has the lowest electron-hole recombination compared to others samples. BiVO₄@PANI composite photocatalysts demonstrated the maximum degradation efficiency compared to pure BiVO₄ and PANI for rhodamine B dye. The probable antimicrobial and photocatalytic mechanisms of the BiVO₄@PANI photocatalyst were proposed. The enhanced antibacterial and photocatalytic activity could be attributed to the high surface area and combined impact of PANI and BiVO₄, which promoted the migration efficiency of photo-generated electron holes. These findings open up ways for the potential use of BiVO₄@PANI in industries, environmental remediation, pharmaceutical and medical sectors. Nevertheless, biocompatibility for human tissues should be thoroughly examined to lead to future improvements in photocatalytic performance and increase antibacterial efficacy.

Hydrothermal synthesis of cobalt substitute zinc-ferrite (Co1-xZnxFe2O4) nanodot, functionalised by polyaniline with enhanced photocatalytic activity under visible light irradiation

Fabrication and development of effective visible-light-responsive photocatalysts are required to tackle critical environmental issues. The aim of this study was to develop a nanocomposite material with improved photocatalytic activity for the degradation of industrial dyes such as Reactive Orange-16 (RO-16), Reactive Blue (RB-222), Reactive Yellow-145 (RY-145), and Disperse Red-1 (DR-1) without the need for a post-separation process after use. Here we report the hydrothermal synthesis of nanodots of Co_1-xZn_xFe₂O₄ (x = 0.3, 0.5 and 0.7), coated with polyaniline, by in situ polymerization. The Co_1-xZn_xFe₂O₄ nanodots, coated with polyaniline (PANI) nanograins, facilitated optical properties by easily capturing visible light. X-ray Diffraction (XRD) patterns and Scanning Electron Microscopy (SEM) images have confirmed the single-phase spinel structure of Co_1-xZn_xFe₂O₄ nanodot and nano-pore size of the Co_1-xZn_xFe₂O₄/PANI nanophotocatalyst. The specific surface area of the Brunauer-Emmett-Teller (BET) of the Co_1-xZn_xFe₂O₄/PANI photocatalyst was determined to be 24.50 m²/g by multipoint analysis. The final Co_1-xZn_xFe₂O₄/PANI (x = 0.5) nanophotocatalyst showed high efficiency in the catalytic degradation of toxic dyes (∼98% within 5 min), with good mechanical stability and recyclability under visible light irradiation. The nanophotocatalyst was re-used and its efficiency was largely maintained, even after seven cycles (∼82%) of degradation. The effects of various parameters, such as initial dye concentration, nanophotocatalyst concentration, initial pH of dye solution, and reaction kinetics were studied. According to the Pseudo-first-order kinetic model, photodegradation data followed the first-order reaction rate (R² > 0.95) of degradation of dyes. In conclusion, a simple and low-cost synthesis process, speedy degradation and excellent stability of polyaniline-coated Co_1-xZn_xFe₂O₄ nanophotocatalyst could be used as a promising photocatalyst for dye-wastewater treatment.

Synthesis of Bimetallic BiPO4/ZnO Nanocomposite: Enhanced Photocatalytic Dye Degradation and Antibacterial Applications

Multidrug-resistant strains (MDRs) are becoming a major concern in a variety of settings, including water treatment and the medical industry. Well-dispersed catalysts such as BiPO₄, ZnO nanoparticles (NPs), and different ratios of BiPO₄/ZnO nanocomposites (NCs) were synthesized through hydrothermal treatments. The morphological behavior of the prepared catalysts was characterized using XRD, Raman spectra, PL, UV-Vis diffuse reflectance spectroscopy (UV-DRS), SEM, EDX, and Fe-SEM. MDRs were isolated and identified by the 16s rDNA technique as belonging to B. flexus, B. filamentosus, P. stutzeri, and A. baumannii. The antibacterial activity against MDRs and the photocatalytic methylene blue (MB) dye degradation activity of the synthesized NPs and NCs were studied. The results demonstrate that the prepared BiPO₄/ZnO-NCs (B1Z4-75:300; NCs-4) caused a maximum growth inhibition of 20 mm against A. baumannii and a minimum growth inhibition of 12 mm against B. filamentosus at 80 μg mL^-1 concentrations of the NPs and NCs. Thus, NCs-4 might be a suitable alternative to further explore and develop as an antibacterial agent. The obtained results statistically justified the data (p ≤ 0.05) via one-way analysis of variance (ANOVA). According to the results of the antibacterial and photocatalytic study, we selected the best bimetallic NCs-4 for the photoexcited antibacterial effect of MDRs, including Gram ve⁺ and Gram ve^- strains, via UV light irradiation. The flower-like NCs-4 composites showed more effectiveness than those of BiPO₄, ZnO, and other ratios of NCs. The results encourage the development of flower-like NCs-4 to enhance the photocatalytic antibacterial technique for water purification.

Immobilization of Polymers to Surfaces by Click Reaction for Photocatalysis with Recyclability

A surface-bound photocatalyst offers advantages of reusability and recyclability with ease. While it can be immobilized by spin coating or drop-casting, a more reliable and durable method involves the formation of a self-assembled monolayer (SAM) on a suitable surface using designer molecules. In this paper, we report devising a practical, durable, and recyclable photocatalytic surface using immobilized polytriazoles of diketopyrrolopyrrole (DPP). While the SAM formation techniques were utilized for superior results, conventional coatings of polymers on surfaces were performed for comparison. Different methods confirmed efficient immobilization and high grafting density for the SAM technique. Computational models suggested favorable energy parameters for active materials. Photocatalytic studies were performed using both immobilized polymers and polymers in solution for comparison. These findings are important for understanding various physicochemical characteristics of polytriazole-functionalized surfaces.

Existence of Ti3+ and dislocation on nanoporous CdO-TiO2 heterostructure applicable for degrading chlorophenol pollutant

This study addresses the significance of wastewater recuperation by a simple and facile treatment process known as photocatalyst technology using visible light. Titanium di-oxide (TiO₂) is the most promising photocatalyst ever since longing decades, has good activity under UV light, owing to its small band gap. Hence, TiO₂ has been modified with metal oxides for the positive response against visible light. Since this is an efficient process, the novelty has been made on nanometal oxide CdO (cadmium oxide) combined with TiO₂ to acquire the best efficiency of degrading organic chlorophenol contaminant. Initially, the composites were synthesized by sol-gel and thermal decomposition methods and investigated for their various outstanding properties. The characterized outcomes have exhibited heterostructures with reduced crystallite size from the X-ray diffraction studies. Then, the determination of nanoporous feature was recognized through HR-TEM analysis which was also detected with some dislocations. The EDX spectrum was identified the perfect elemental composition. The nitrogen adsorption-desorption equilibrium was attained that offers many pores measured with high surface area. The XPS result convinced that Ti³⁺ was accessible along with TIO₂/CdO composite. Further the absorption towards higher wavelength was obtained from UV-vis spectra. Finally, for the photocatalytic application of chlorophenol, the composite shows higher percentage of degrading efficiencies than the pristine TiO₂. The photocatalytic mechanism was discussed in detail.

Photocatalytic dye degradation and photoexcited anti-microbial activities of green zinc oxide nanoparticles synthesized via Sargassum muticum extracts

Drug-resistant superbugs (DRS) were isolated from hospital sewage waste and confirmed by a 16S rDNA molecular technique as B. filamentosus, B. flexus, P. stutzeri, and A. baumannii. Green nanotechnologies provide a new promising alternative pathway that was found to be much safer, eco-friendly, and has economic benefits over physical/chemical methods. Sargassum muticum (SM) mediated zinc oxide nanoparticles (ZnO-NPs) were proved to be photocatalytic and anti-microbial agents. Anti-microbial action was demonstrated by a maximal growth inhibition activity of 18 mm against A. baumannii and a minimal of 12 mm against B. flexus at 80 μg mL-1 concentrations. The anti-microbial mechanism of SMZnO-NPs employed a biphasic phenomenon persuaded by an osmotic shock that can attack the DRS bacterial cells directly and lead to death. In addition, photocatalytic activity was investigated by SMZnO-NPs for the degradation of methylene blue (MB) dye under different light conditions. Natural sunlight irradiation shows effective enhancement with the highest efficiencies of 96% being achieved within 60 min compared to UV-light and visible-light. The reusability of SMZnO-NPs provides up to 6 consecutive cycles towards MB decolorization for environmental water cleansing.

A photocatalytic chip inspired from the photovoltaics of polymer-immobilized surfaces: self-assembly and other factors

Polymers and carbon nanomaterials for bulk heterojunction photovoltaic devices have been used to develop an efficient reusable photocatalytic chip. Interestingly, it is highly effective when the materials are self-assembled in a particular pattern at a particular concentration ratio (Movies in the ESI).

Synergizing Functional Nanomaterials with Aptamers Based on Electrochemical Strategies for Pesticide Detection: Current Status and Perspectives

Owing to the high toxicity and large-scale use of pesticides, it is imperative to develop selective, sensitive, portable, and convenient sensors for rapid monitoring of pesticide. Therefore, the electrochemical detection platform offers a promising analytical approach since it is easy to operate, economical, efficient, and user-friendly. Meanwhile, with advances in functional nanomaterials and aptamer selection technologies, numerous sensitivity-enhancement techniques alongside a widespread range of smart nanomaterials have been merged to construct novel aptamer probes to use in the biosensing field. Hence, this study intends to highlight recent development and promising applications on the functional nanomaterials with aptamers for pesticides detection based on electrochemical strategies. We also reviewed the current novel aptamer-functionalized microdevices for the portability of pesticides sensors. Furthermore, the major challenges and future prospects in this field are also discussed to provide ideas for further research.

Conducting polymers: a comprehensive review on recent advances in synthesis, properties and applications

Conducting polymers are extensively studied due to their outstanding properties, including tunable electrical property, optical and high mechanical properties, easy synthesis and effortless fabrication and high environmental stability over conventional inorganic materials. Although conducting polymers have a lot of limitations in their pristine form, hybridization with other materials overcomes these limitations. The synergetic effects of conducting polymer composites give them wide applications in electrical, electronics and optoelectronic fields. An in-depth analysis of composites of conducting polymers with carbonaceous materials, metal oxides, transition metals and transition metal dichalcogenides etc. is used to study them effectively. Here in this review we seek to describe the transport models which help to explain the conduction mechanism, relevant synthesis approaches, and physical properties, including electrical, optical and mechanical properties. Recent developments in their applications in the fields of energy storage, photocatalysis, anti-corrosion coatings, biomedical applications and sensing applications are also explained. Structural properties play an important role in the performance of the composites.

The design of a polyaniline-decorated three dimensional W18O49 composite for full solar spectrum light driven photocatalytic removal of aqueous nitrite with high N2 selectivity

Photocatalysis using solar energy is the most promising green technology for nitrite removal. However, effective photocatalytic performance is often challenged by the limited light absorption, utilization of expensive noble metals and undesired products (nitrate and ammonium). Here, we report for the first time that a full solar light response polyaniline-decorated three dimensional W₁₈O₄₉ composite (PANI@W₁₈O₄₉), a noble metal-free photocatalyst, possesses excellent photocatalytic activity for aqueous nitrite removal with high N₂ selectivity. The prepared sample was thoroughly identified via XRD, Raman, FTIR, SEM, TEM, UV-vis DRS and PL. The catalytic results demonstrated that over 80% N₂ selectivity (initial concentration 1.0 mM) was achieved through the PANI@W₁₈O₄₉ without sacrificial agent under 300 W Xe lamp irradiation for 60 min. Such advantages were attributed to the built-in junction between n-type W₁₈O₄₉ and p-type PANI, offering suitable redox levels of electron-hole pairs for NO₂^- reaction. The modification of PANI also benefited the light harvesting ability and activated carriers migration, the calculated rate constant of PANI@W₁₈O₄₉ is about four times as high as that of W₁₈O₄₉. The current study not only prepared a promising photocatalyst, but also provides new insights into improving the photocatalytic activity and N₂ selectivity for nitrite treatment.

A magnetically recyclable photocatalyst with commendable dye degradation activity at ambient conditions

An efficient, economical, environment-friendly and easy separable catalyst to treat environmental contaminants is an enduring attention in recent years due to their great potential for environmental protection and remediation. Here we have reported the excellent performance of polyaniline activated heterojunctured Ni_0.5Zn_0.5Fe₂O₄ catalyst to degrade azo dye in an aqueous solution at ambient condition. The catalyst was prepared via a simple facile polymerization procedure. The physicochemical properties and structure of the synthesized catalyst was confirmed by TGA, PXRD, FTIR, SEM, HRTEM, XPS, EDX, and DRS techniques. The developed catalyst has shown an accelerated degradation ability of an organic pollutant Orange ll Sodium salt azo dye about 100% for the dye concentration of 50 ppm within five minutes at ambient conditions with 1 g/l loading of catalyst. Simple facile synthesis, easy separation by an external magnet, good reusability and high degradation capability of the catalyst may promote the practical applications of the heterostructured catalyst at ambient condition for water remediation. The present study also explored possible credible charge transfer directions and mechanism of photocatalysis supported by trapping experiments and electrochemical impedance spectroscopy (EIS) measurement for the effective improvement of photocatalytic activity and enhancement of the visible light adsorption.

TiO2-PANI/Cork composite: A new floating photocatalyst for the treatment of organic pollutants under sunlight irradiation

A novel photocatalyst based on TiO₂-PANI composite supported on small pieces of cork has been reported. It was prepared by simple impregnation method of the polyaniline (PANI)-modified TiO₂ on cork. The TiO₂-PANI/Cork catalyst shows the unique feature of floating on the water surface. The as-synthesized catalyst was characterized by X-ray diffraction (XRD), scanning electron micrograph (SEM), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FT-IR), UV-vis diffuse reflectance spectra (UV-vis DRS) and the Brunauer-Emmett-Teller (BET) surface area analysis. Characterization suggested the formation of anatase highly dispersed on the cork surface. The prepared floating photocatalyst showed high efficiency for the degradation of methyl orange dye and other organic pollutants under solar irradiation and constrained conditions, i.e., no-stirring and no-oxygenation. The TiO₂-PANI/Cork floating photocatalyst can be reused for at least four consecutive times without significant decrease of the degradation efficiency.

Recent Advances in Nanostructured Conducting Polymers: from Synthesis to Practical Applications

Conducting polymers (CPs) have been widely studied to realize advanced technologies in various areas such as chemical and biosensors, catalysts, photovoltaic cells, batteries, supercapacitors, and others. In particular, hybridization of CPs with inorganic species has allowed the production of promising functional materials with improved performance in various applications. Consequently, many important studies on CPs have been carried out over the last decade, and numerous researchers remain attracted to CPs from a technological perspective. In this review, we provide a theoretical classification of fabrication techniques and a brief summary of the most recent developments in synthesis methods. We evaluate the efficacy and benefits of these methods for the preparation of pure CP nanomaterials and nanohybrids, presenting the newest trends from around the world with 205 references, most of which are from the last three years. Furthermore, we also evaluate the effects of various factors on the structures and properties of CP nanomaterials, citing a large variety of publications.

SrTiO₃ Nanocube-Doped Polyaniline Nanocomposites with Enhanced Photocatalytic Degradation of Methylene Blue under Visible Light

The present study highlights the facile synthesis of polyaniline (PANI)-based nanocomposites doped with SrTiO₃ nanocubes synthesized via the in situ oxidative polymerization technique using ammonium persulfate (APS) as an oxidant in acidic medium for the photocatalytic degradation of methylene blue dye. Field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), X-ray diffraction (XRD), UV⁻Vis spectroscopy, Brunauer⁻Emmett⁻Teller analysis (BET) and Fourier transform infrared spectroscopy (FTIR) measurements were used to characterize the prepared nanocomposite photocatalysts. The photocatalytic efficiencies of the photocatalysts were examined by degrading methylene blue (MB) under visible light irradiation. The results showed that the degradation efficiency of the composite photocatalysts that were doped with SrTiO₃ nanocubes was higher than that of the undoped polyaniline. In this study, the effects of the weight ratio of polyaniline to SrTiO₃ on the photocatalytic activities were investigated. The results revealed that the nanocomposite P-Sr500 was found to be an optimum photocatalyst, with a 97% degradation efficiency after 90 min of irradiation under solar light.

Ultrasonic-mediated synthesis and characterization of TiO2-loaded chitosan-grafted-polymethylaniline nanoparticles of potent efficiency in dye uptake and sunlight driven self-cleaning applications

In the present study, a new sequential process for wastewater remediation in two steps with high durability was presented.

Construction of five Zn(ii)/Cd(ii) coordination polymers derived from a new linear carboxylate/pyridyl ligand: design, synthesis, and photocatalytic properties

Reactions of Cd(OAc)₂/Zn(OAc)₂ with a new linear carboxylate/pyridyl ligand under different templates via an in situ ligand transformation reaction produced five new CPs. Complexes 1–5 exhibited relatively good photocatalytic activity towards the degradation of methylene blue.

Immobilization of cadmium ions to synthesis hierarchical flowerlike cadmium phosphates microspheres and their application in the degradation of organic pollutants under light irradiation

Hierarchical flowerlike Cd₅H₂(PO₄)₄·4H₂O and Cd₅(PO₄)₂P₂O₇ microspheres were prepared by cadmium ion immobilization followed by an annealing treatment. Cd₅(PO₄)₂P₂O₇ was applied as a novel photocatalyst toward dye degradation under light irradiation.

A novel electrochemical sensor based on zirconia/ordered macroporous polyaniline for ultrasensitive detection of pesticides

A simple and mild strategy was proposed to develop a novel electrochemical sensor based on zirconia/ordered macroporous polyaniline (ZrO₂/OMP) and further used for the detection of methyl parathion (MP), one of the organophosphate pesticides (OPPs).

Conjugated polymer/nanocrystal nanocomposites for renewable energy applications in photovoltaics and photocatalysis

Conjugated polymer/nanocrystal composites have attracted much attention for use in renewable energy applications because of their versatile and synergistic optical and electronic properties. Upon absorbing photons, charge separation occurs in the nanocrystals, generating electrons and holes for photocurrent flow or reduction/oxidation (redox) reactions under proper conditions. Incorporating these nanocrystals into conjugated polymers can complement the visible light absorption range of the polymers for photovoltaics applications or allow the polymers to sensitize or immobilize the nanocrystals for photocatalysis. Here, the current developments of conjugated polymer/nanocrystal nanocomposites for bulk heterojunction-type photovoltaics incorporating Cd- and Pb-based nanocrystals or quantum dots are reviewed. The effects of manipulating the organic ligands and the concentration of the nanocrystal precursor, critical factors that affect the shape and aggregation of the nanocrystals, are also discussed. In the conclusion, the mechanisms through which conjugated polymers can sensitize semiconductor nanocrystals (TiO2 , ZnO) to ensure efficient charge separation, as well as how they can support immobilized nanocrystals for use in photocatalysis, are addressed.

Recent advances in heterogeneous photocatalytic decolorization of synthetic dyes

During the process and operation of the dyes, the wastes produced were commonly found to contain organic and inorganic impurities leading to risks in the ecosystem and biodiversity with the resultant impact on the environment. Improper effluent disposal in aqueous ecosystems leads to reduction of sunlight penetration which in turn diminishes photosynthetic activity, resulting in acute toxic effects on the aquatic flora/fauna and dissolved oxygen concentration. Recently, photodegradation of various synthetic dyes has been studied in terms of their absorbance and the reduction of oxygen content by changes in the concentration of the dye. The advantages that make photocatalytic techniques superior to traditional methods are the ability to remove contaminates in the range of ppb, no generation of polycyclic compounds, higher speed, and lower cost. Semiconductor metal oxides, typically TiO₂, ZnO, SnO, NiO, Cu₂O, Fe₃O₄, and also CdS have been utilized as photocatalyst for their nontoxic nature, high photosensitivity, wide band gap and high stability. Various process parameters like photocatalyst dose, pH and initial dye concentrations have been varied and highlighted. Research focused on surface modification of semiconductors and mixed oxide semiconductors by doping them with noble metals (Pt, Pd, Au, and Ag) and organic matter (C, N, Cl, and F) showed enhanced dye degradation compared to corresponding native semiconductors. This paper reviews recent advances in heterogeneous photocatalytic decolorization for the removal of synthetic dyes from water and wastewater. Thus, the main core highlighted in this paper is the critical selection of semiconductors for photocatalysis based on the chemical, physical, and selective nature of the poisoning dyes.

Template-free syntheses of CdS microspheres composed of ultrasmall nanocrystals and their photocatalytic study

A one-pot, template-free, solvothermal method for synthesizing CdS microspheres composed of ultrasmall (∼2 nm) nanocrystals without and with the use of MCE-capping agent has been developed. The photocatalytic activity of the microspheres for degradation of MO under UV and natural sunlight irradiation has been compared.