Photocatalytic Applications Research Articles

Synergistic impacts of novel tantalum doping in BiVO4 for effective photocatalytic applications, antimicrobial activity, and antioxidant aspect

This paper reports the production of pure and Ta-doped (1 %, 2 %, 3 %, and 4 %) BiVO4 nanoparticles (NPs) for MB dye degradation. UV–Vis, FTIR, SEM, PL, and XRD techniques were used to analyze the samples. Photocatalysts (BiVO4, Ta-doped BiVO4) NPs have been used to study the photocatalytic activity of these materials for the degradation of methylene blue (MB) in response to visible light. The band gap reduction from 2.7 to 1.98 eV and the photogeneration of electron-hole pairs have also been demonstrated by UV–visible and PL spectroscopy. According to FTIR spectroscopy analysis, Bismuth, Tantalum, Vanadium, Oxygen, and Carbon are all present in the synthesized material. As the dopant concentration rises, the XRD data show that the crystallite size decreases. The crystallite size of the optimal (4 % Ta-doped BiVO4) is 23 nm, whereas the crystallite size of the 2 % Ta-doped BiVO4 is 39 nm. The SEM image shows that particle size reduces when dopant concentration rises. In comparison to previous synthesized materials, the 4 % Ta-doped BiVO4 NPs have a smaller band gap, crystalline size, and recombination rate. Therefore, using the co-precipitation process, 4 % Ta-doped BiVO4 NPs degrade the MB dye (86 %) in 120 min, making them an ideal material. The findings of this study will be applied to wastewater treatment.

Cr3+doped α-Fe2O3 nanoparticles for photodegradation of organic pollutants with their disinfection efficacy

Pristine and Cr-doped α-Fe2O3 nanoparticles were synthesized using a low-cost and simple one-step hydrothermal method without any precipitating agent. Cr-doped α-Fe2O3 was found to be a promising candidate for recyclable photocatalytic application for Tetracycline (TC) and Congo-red (CR) degradation under normal sunlight irradiation along with excellent antibacterial properties. Addition of Cr shows a significantly improved degradation efficiency from 20% to 91% in just 25 min for CR, while the degradation rate reached to 81% for TC, which was also monitored in real-time using internet of things (IoT). Also, a high degree of mineralization was achieved (∼87.9%), which was confirmed using total organic carbon (TOC) content. In parallel, the biochemical oxygen demand/chemical oxygen demand (BOD5/COD) ratio confirmed the fast degradation efficiency using a small amount of catalytic dosage (∼ 0.40 g/L). Also, degradation of multiple dyes provides a promising avenue for addressing complex waste water treatment challenges. Moreover, Cr-doped α-Fe2O3 displays excellent antibacterial activity towards E.coli and E.Faecium. Major factors involved in sunlight driven photocatalytic activity for example absorbance range, porosity, separation between e--h+, and charge transfer property were surprisingly improved by Cr doping and henceforth increased photocatalytic activity and antibacterial properties. This work highlights the potential utilization of Cr-doped α-Fe2O3 for the purification and disinfection of industrial waste water.

Synthesis, characterization, and photocatalytic performance of gold ions implanted TiO2/graphene nanocomposites for efficient dye photodegradation

The suggested work provides a hydrothermal technique for the synthesis of TiO2/graphene nanocomposites with different weight percentages of graphene (0.0 %, 5.0 %, 10.0 %, and 15.0 %). These composites were implanted with gold ions at a fluence of 1 × 1013 ions/cm2 by using a pelletron accelerator. The structural and physical properties were investigated by utilizing XRD, FESEM, FTIR, EDX, and UV–Vis spectroscopy. The XRD data verified the existence of TiO2 with a rutile crystal phase. FESEM morphology showed that TiO2 particles had aggregated on graphene layers and had a semi-spherical shape. The functional groups present in the sample were identified using FTIR for TiO2 and TiO2/graphene nanocomposites. The stoichiometric ratios of all the constituent elements and the homogeneous composition were confirmed using EDX analysis. The UV–Vis spectroscopy revealed that the optical bandgap decreased from 3.15 eV to 2.80 eV. Additionally, the photocatalytic activity for the degradation of methylene blue (MB) under UV light was investigated. The photocatalytic performance was improved with increased graphene content. The evaluated data reveals that the sample with 10 % graphene has the maximum photocatalytic activity and rate constant. These findings suggest that gold-implanted TiO2/graphene nanocomposites favor photocatalytic applications and use in dye-sensitized solar cells.

Photocatalytic and thermoelectric properties of Cu2SrSnS4 nanoparticles by solvothermal method

In the present work, flower-like Cu2SrSnS4 (CSTS) sample is successfully prepared by solvothermal method. The XRD and Raman analysis confirm that pure CSTS phase with trigonal structure is obtained. The band gap of as-obtained CSTS naocrystals is estimated to be 1.49eV. The removal of methylene blue (MB) within 100min under simulated solar light irradiation is around 90%, depicting that CSTS is a potential material for effective solar light photocatalytic application. Meanwhile, The Seebeck coefficient and electrical conductivity of CSTS material can reach to 128.57μV•K-1 and 20.35S·m-1 at 675K, respectively, indicating its potential for thermoelectric application.

Comparative study of anodized TNTs and S-TNTs on Ti plates for effective methylene blue degradation under UV LED and direct sunlight

The key findings of this research are focused on enhancing the degradation of methylene blue dye with titania nanotubes acting as catalysts under benign UV LED and sunlight. By comparing pristine and sulfur-doped titania, the study reveals that the doped-titania with anatase phase demonstrates a superior photocatalytic activity than pristine titania with mixed phases, achieving a remarkable 98 % degradation of dye within 120 min under direct sunlight with a small amount of hydrogen peroxide. This enhanced performance is attributed to the 10.7 μm longer and well-arranged nanotubes, effective surface area, better bandgap of 2.39 eV, effective anatase phases, and a lower 20 nm crystallite size. The study underscores the importance of anodization and sulfur doping using titanium plates to tailor the properties of the resultant nanotubes. Also, it indicates a cost-effective dye removal method without secondary pollution, offering a practical and optimistic solution to environmental challenges. The effective titania nanotubes for photocatalytic application in environmental remediation were identified through field emission scanning electron microscope, energy dispersive X-ray analysis, X-ray diffraction analysis, and diffuse reflectance analysis, providing valuable insights and inspiring future research and application in this field.

Green synthesis of undoped and yttrium, bismuth co-doped titanium dioxide nanoparticles using Bryophyllum pinnatum for photocatalytic application

In this research, a non-toxic, inexpensive, and environment-friendly green synthesis route was investigated to synthesize undoped and Y, Bi co-doped TiO2 nanoparticles by using Bryophyllum pinnatum leaf extract. Precursor material titanium isopropoxide (TTIP) was utilized for both undoped and co-doped TiO2 and Yttrium and Bismuth were added to 1, 2, and 3 percent as co-dopants. The obtained undoped and Y, Bi co-doped TiO2 nanoparticles were characterized by various analytical techniques, which include X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), and UV–Visible spectroscopy for the evaluation of the structural, morphological, and photocatalytic activity. Anatase phase formation was observed from the XRD analysis for both undoped and Y, Bi co-doped TiO2 nanoparticles. The average particle size for undoped TiO2 nanoparticles was found to be 15.92 nm which raised to 21.70 nm for 3 % co-doping. UV–Vis Spectroscopy analysis revealed a reduction on band gap energy (Eg) for Y, Bi co-doped TiO2 nanoparticles. Methylene blue (MB) photodegradation demonstrates co-doping with Y, Bi significantly increases the photocatalytic activity. Overall, green synthesis using Bryophyllum pinnatum was found to be an economical method to fabricate TiO2 NPs that shows great improvement in photo-degradation characteristics.

Screening Transition-Metal-Incorporated β-AgVO3 for Augmented Oxygen Reduction Activity.

Exploring cost-effective alternatives to Pt-based catalysts for the oxygen reduction reaction (ORR) in fuel cells is crucial for their large-scale deployment in green energy applications. Silver vanadate (AgVO3) is a well-studied material for photocatalytic applications. Here, we investigate the electrocatalytic ORR activity of the thermodynamically stable β phase of AgVO3 through computational modeling based on DFT. It is found that β-AgVO3 exhibits weak catalytic activity for the ORR, with vanadium being the preferable active site. Incorporating single atoms of transition metals at surface-level vacancies in β-AgVO3 significantly modifies the ORR activity. We study the scaling of free energy changes for the ORR intermediates *OOH, *OH, and *O for various transition metals incorporated, which leads to an optimal overpotential for the system. The optimal overpotential thus obtained is remarkably lower than that of pristine β-AgVO3. For the transition metal atoms we consider here, Co-incorporated β-AgVO3 exhibits the best ORR catalytic activity due to its optimal binding of ORR species to the vanadium site. It is also observed that some of the transition metals considered like Re, Rh, Os, or Mn show weak activity, either due to strong or weak binding. Analysis of the electronic structure of the adsorbate-catalyst interface shows a strong correlation between optimal activity and evolution of midgap states in β-AgVO3, due to transition metal incorporation. Our study concludes that the ORR activity of a stable mixed transition metal oxide like β-AgVO3 can be enhanced with a minimal loading of transition metals, which could help in developing a novel series of ORR catalysts.

Synthesis and characterization of rGO/AgCeO2 nanocomposite for photocatalytic application

Synthesis and characterization of rGO/AgCeO2 nanocomposite for photocatalytic application

2D porous hexaniobate-bismuth vanadate hybrid photocatalyst for photodegradation of aquatic refractory pollutants

Metal oxide semiconductors are highly promising due to their excellent photocatalytic performance in the photodegradation of industrial waste containing refractory chemical compounds. A hybrid structure with other semiconductors provides improved photocatalytic performance. In this work, porous and two-dimensional (2D) hexaniobate-bismuth vanadate (Nb6-BiVO4) Z-scheme hybrid photocatalysts are synthesized by chemical solution growth (CSG) of BiVO4 over electrophoretically deposited Nb6 thin films. The structural and morphological analysis of Nb6-BiVO4 hybrid thin films evidenced the well-crystalline uniform growth of monoclinic scheelite BiVO4 over lamellar Nb6 nanosheets. The Nb6-BiVO4 hybrid thin films exhibit a highly porous randomly aggregated nanosheet network, creating the house-of-cards type morphology. The Nb6-BiVO4 hybrid thin films display a strong visible light absorption with band gap energy of 2.29 eV and highly quenched photoluminescence signal, indicating their visible light harvesting nature and intimate electronic coupling between hybridized species beneficial for photocatalytic applications. The visible-light-driven photodegradation performance of methylene blue (MB), rhodamine-B (Rh-B) dyes, and tetracycline hydrochloride (TC) antibiotic over Nb6-BiVO4 hybrid are studied. The best optimized Nb6-BiVO4 thin film shows superior photocatalytic activity for photodegradation of MB, Rh-B dyes, and TC antibiotic with photodegradation rates of 87.3, 92.8, and 64.7 %, respectively, exceptionally higher than that of pristine BiVO4. Furthermore, the mineralization study of Nb6-BiVO4 thin film is conducted using chemical oxygen demand (COD) analysis. The optimized Nb6-BiVO4 thin film shows superior percentage COD removal of 83.33, 85.42, and 61.36 % for MB, Rh-B dyes and TC antibiotic, respectively. The present results highlight the expediency of hybridization in enhancing the photocatalytic activity of pristine BiVO4 by minimizing its charge recombination rate and improving chemical stability.

Engineering the plasmonic activities of copper nanostructures for SERS and photocatalysis

Nanoparticles of plasmonic metals such as gold (Au), silver (Ag) and copper (Cu) have numerous applications due to their localized surface plasmon resonance. Among these, nanoparticles of Cu remain underexplored when compared to Au and Ag, although the former is much cheaper. Here we report the surface enhanced Raman spectroscopy (SERS), interaction of molecule with a plasmonics and photocatalysis applications of Cu nanostructures. Hexagonal and cubic shaped Cu nanostructures were successfully synthesized by varying the reaction conditions in a polyol synthesis method. Rapid nucleation at an elevated temperature (140 °C) and subsequent slow growth at lower temperature (80 °C) in presence of polymeric stabilizer resulted in the formation of uniform cube shaped Cu nanoparticles (Cucube). Whereas polyol synthesis at a low temperature (80 °C) resulted in hexagonal Cu nanoparticles (Cuhex). Both the nanostructures exhibited very good surface enhanced Raman scattering (SERS) enhancement of the order 6.9 × 105 for rhodamine B (RhB). Cuhex also showed reliable SERS sensing of RhB with a very low experimental limit of detection (10−10 M). Moreover, based on emission and time-dependent measurements, strong molecular and plasmonic interactions reveal energy transfer from RhB molecules to the Cu nanostructures. Additionally, Cuhex showed very good catalytic and visible light plasmonic photocatalytic activities for the para-nitrophenol (p-NP) reduction reaction.

Blue to UV upconversion properties of Pr3+ doped ACaF3 (A = K, Rb, Cs) phosphors

Materials capable of converting visible light into the ultraviolet C (UVC) region are promising candidates for antimicrobial technology and photocatalytic applications. In this work, the effective UVC upconversion phosphors ACaF3:Pr3+ (A = K, Rb, Cs) were synthesized using solid state reactions. Upconverted emissions in the range from 230 to 315 nm were obtained with 444 nm laser excitation. The dependence of upconverted luminescence on pump power, the concentration of Pr3+ ions, and the decay profiles of upconverted luminescence provide insights into the primary mechanisms responsible for upconversion. Among the obtained fluoroperovskites, the rubidium composition showed the most intense luminescence. Additionally, ACaF3:1 %Pr3+ exhibits a manifold increase in upconversion emission compared to the previously studied reference material LiYF4:1 %Pr3+, indicating the potential use of fluoroperovskites for surface decontamination.

Pristine and Nature‐Inspired Hematite (α‐Fe2O3) Nanoparticles and Search for their Photocatalytic Application

AbstractThe article describes synthesis of green‐mediated hematite nanoparticles (20–30 nm) using Polianthes tuberosa flower extract. Structural, microscopic, and magnetic studies confirm the synthesis of iron oxide nanoparticles of pure hematite phase. Spectroscopic techniques are employed to identify different electronic transitions and defect levels as well as to estimate the energy bandgap and Urbach energy. A correlation among the particle size, bandgap energy, and Urbach energy is noticed. These hematite nanoparticles act as visible light photocatalyst which degrade dye in aqueous medium without the addition of any additives. The catalyst particle size, catalyst quantity, pH of dye solution, and solution temperature have significant impact on the photodegradation process of dye molecules in aq. solution. All observations advocate that green synthesis of hematite nanoparticles with Polianthes tuberosa flower extract can significantly modulate their optical and photocatalytic properties. These materials may find potential uses in water splitting for hydrogen production and purification of water by removing organic pollutants. The study highlights that using commercially cheap starting materials and extract made from naturally available plant parts, materials having huge application potentials can be synthesized at low cost by the simple green synthesis approach.

An Effective and Controllable Platform with Ag-Stepped Nanocone Arrays Serving as Stable SERS Substrate

Facile, controllable and efficient SERS substrate preparation has always been the focus project in the SERS field, especially the solid-state nanoarray substrate. Herein, a simple and convenient method for preparing a series of homogeneous Ag-stepped nanocone arrays (Ag-SNCAs) using polymer nanocompression printing is presented. By analyzing the 1162[Formula: see text]cm[Formula: see text] characteristic peak of crystal violet (CV), the relative standard deviation (RSD) of the Raman intensity was only 4.71%. The detection limit of malachite green (MG) reached 0.001[Formula: see text]ppm, and it also has good SERS detection results for drug molecules such as melamine, methadone, morphine, methamphetamine and thiabendazole. This work provides a large area uniform and controllable preparation method of sharp cone nanostructure array, which has important application in plasmonic photocatalysis and deep light field regulations.

In Situ Synthesis of ZnCo2O4 and Pd@ZnCo2O4 Nanocomposites for Dye Degradation and Biological Applications

In this study, ZnCo2O4 and Pd@ZnCo2O4 were synthesized through a novel phytochemical process using the leaf extract of Catharanthus roseus for photocatalytic and biological applications. The synthesized nanoparticles were characterized through X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy, Fourier-transform infrared spectroscopy, and UV-Visible spectroscopy. The photocatalytic activities of ZnCo2O4 and Pd@ZnCo2O4 (10 mg) were evaluated after 40 min of reaction by degrading brilliant blue dye (100 µg/mL solution), achieving 42% and 97% degradation, respectively. This green synthesis method for ZnCo2O4 and Pd@ZnCo2O4 proves to be an eco-friendly, modest, and effective approach for the photodegradation of brilliant blue dye in an aqueous medium. Additionally, the ZnCo2O4 and Pd@ZnCo2O4 catalysts were also tested for their antibacterial and antioxidant activities.

Supercapacitor and Photocatalytic Applications of Hydrothermally Synthesized of Polydymite Nanoparticles

The hydrothermal technique for producing polydymite nanoparticles (Ni3S4 NPs) for photocatalytic and supercapacitor utilization is the main emphasis in present work. The microstructural and electrochemical characterizations were conducted to determine the performance parameters of supercapacitor such as specific capacitance, efficiency, energy density and power density values using cyclic voltammetric (CV) and electrochemical impedance spectroscopic (EIS) techniques. The electrochemical characteristics of Ni3S4 NPs were studied using a TMS electrode in a 2 M KOH solution. This showed a specific capacitance value of 524 F g–1 at a current density of 1 A g–1. The Ni3S4 NPs showed good photocatalytic activities for the photodegradation of fast blue dye, the Ni3S4 NPs exhibits a 75.6% colour loss rate following the exposure for 120 min to UV radiation.

ZnSnS Nanoparticles Synthesized by Simple SMI Technique for Photocatalytic Application

Photocatalysis, driven by semiconductor nanoparticles under visible or ultraviolet light, has emerged as a powerful and sustainable approach for environmental remediation and clean energy production. In this study, we investigate the photocatalytic potential of tin (0, 2, 4, 6, 8, 10) mole % alloyed with zinc sulfide (ZnSnS) nanoparticles as efficient catalysts for various environment and energy-related applications. ZnSnS nanoparticles were produced via a simple microwave irradiation technique. Comprehensive structural characterization through X-ray diffraction (XRD), FESEM, EDAX and HRTEM confirmed the successful incorporation of tin atoms into the ZnS crystal lattice. Optical study indicated significant blue shifts in the absorption edge, extending the light absorption into the visible region, a key advantage for photocatalytic applications. Photocatalytic experiments were conducted to evaluate the performance of Zn-alloyed SnS nanoparticles in degrading organic pollutants and hydrogen evolution from water splitting reactions. Our results revealed remarkable enhancements in photocatalytic activity. The enhanced efficiency can be credited to the creation of fresh energy levels within the bandgap, aiding in the separation and movement of charges, and also to the heightened light absorption caused by the reduced bandgap. Furthermore, stability tests indicated the durability of (ZnSnS) nanoparticles, making them suitable candidates for long-term applications in real-world environments. The observed photocatalytic activity enhancements hold promise for addressing environmental issues, including wastewater treatment, air purification, and hydrogen production for clean energy.

Facile Synthesis and Characterization of Pure and Bi-doped ZnS Nanoparticles for Photocatalytic Application

In the present research, a simple solvothermal microwave irradiation (SMI) method has been adopted for the preparation and synthesis of pure and Bi doped ZnS nanoparticles using zinc acetate, bismuth acetate, thiourea and ethylene glycol were utilized as precursors. As-synthesized pure and Bi doped ZnS nanoparticles were characterized by X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDAX), ultraviolet-visible (UV-vis) spectroscopy and Field emission scanning electron microscopy (FESEM). From the XRD and EDAX studies, crystallite size, lattice parameter and analysis of the elemental compositions are calculated and analyzed respectively. The UV-vis spectra revealed that the optical band gap energy of pure and Bi doped ZnS nanoparticles was calculated. The FESEM shows that the average particle size spherical and agglomerated of as-synthesized pure and Bi doped ZnS nanoparticles sizes were decreased. In addition, the photocatalytic activity of pure and Bi doped ZnS nanoparticles was studied with methylene blue dye in an aqueous solution under UV light irradiation; the 5.0 mol % of Bi doped ZnS nanoparticles dye degradation efficiency of the sample was calculated as 75% in 120 minutes.

Organic and Metal–Organic Polymer-Based Catalysts—Enfant Terrible Companions or Good Assistants?

This overview provides insights into organic and metal–organic polymer (OMOP) catalysts aimed at processes carried out in the liquid phase. Various types of polymers are discussed, including vinyl (various functional poly(styrene-co-divinylbenzene) and perfluorinated functionalized hydrocarbons, e.g., Nafion), condensation (polyesters, -amides, -anilines, -imides), and additional (polyurethanes, and polyureas, polybenzimidazoles, polyporphyrins), prepared from organometal monomers. Covalent organic frameworks (COFs), metal–organic frameworks (MOFs), and their composites represent a significant class of OMOP catalysts. Following this, the preparation, characterization, and application of dispersed metal catalysts are discussed. Key catalytic processes such as alkylation—used in large-scale applications like the production of alkyl-tert-butyl ether and bisphenol A—as well as reduction, oxidation, and other reactions, are highlighted. The versatile properties of COFs and MOFs, including well-defined nanometer-scale pores, large surface areas, and excellent chemisorption capabilities, make them highly promising for chemical, electrochemical, and photocatalytic applications. Particular emphasis is placed on their potential for CO2 treatment. However, a notable drawback of COF- and MOF-based catalysts is their relatively low stability in both alkaline and acidic environments, as well as their high cost. A special part is devoted to deactivation and the disposal of the used/deactivated catalysts, emphasizing the importance of separating heavy metals from catalysts. The conclusion provides guidance on selecting and developing OMOP-based catalysts.

Computational study of Rubidium-Rb based cubic Rb2TlCoF6 double perovskite material for photocatalytic water degradation applications: A DFT investigations

The fascinating characteristics, such as straightforward and stable crystal structure, and double perovskites are currently popular materials for applications in renewable energy. In our study, we applied CASTEP and DFT, called density functional theory, to theoretically investigate the mechanical, optical, and thermoelectric characteristics of cubic Rb2TlCoF6. Calculations of the compound Rb2TlCoF6's structural, electrical, optical, mechanical, and thermodynamic properties are made using the GGA-PBE exchange correlational functional and the Fm3m with space group no.225 vol and compound lattice constant are 9.08 Å and 748.613 Å3, respectively. For Rb2TlCoF6, the measured energy band gaps are 1.45 eV. The mechanical and elastic constants are calculated to confirm the ductile properties of Rb2TlCoF6. The brittle characteristics have been verified using Passion and Pugh's ratios, which are 1.67 and 0.25, according to elastic constants. Vickers compound hardness Hv and anisotropy factor “A” are 4.19 and 0.77, respectively. The compounds' optical characteristics reveal significant conductivity and absorption. The compound exhibits high-efficiency photocatalytic activity based on its optical characteristics. Based on mechanical stability, such as Debye temperature, melting temperature, minimum thermal conductivity, average sound velocity, free energy, and other variables, the thermodynamic and structural stabilities are calculated. These materials controlled electrical and other properties make them potentially useful in photocatalytic applications. According to the outcomes, Rb2TlCoF6 is appropriate for photocatalytic water-splitting applications and water deterioration.

Innovations in photocatalytic trifluoromethylation: Role of heterogeneous Bi4NbO8Cl in radical generation

Photocatalytic selective trifluoromethylation reactions have garnered significant attention, particularly for their applications in pharmaceuticals, agrochemicals, and materials science. However, existing heterogeneous catalysts such as graphitic carbon nitride, CdS nanorods, and Au@ZnO core–shell nanoparticles exhibit certain limitations, including low catalytic efficiency, inadequate selectivity, and demanding reaction conditions. To address these challenges, we have developed a novel heterogeneous photocatalyst, i.e., Bi4NbO8Cl, and systematically investigated its performance in visible-light-induced hydroxytrifluoromethylation of alkenes and trifluoromethylation of (hetero)aromatics. Notably, the Bi4NbO8Cl photocatalyst exhibits remarkable stability and reusability, maintaining its performance and structural integrity over five cycles. These findings highlight the economic and practical potential of Bi4NbO8Cl, positioning it as a promising candidate for industrial applications in photocatalysis.