Sustainable Photocatalyst Research Articles

Hierarchical TiO2 nanostructures sensitized with MoS2 nanosheets: an efficient and reusable heterojunction photocatalyst for sunlight-assisted degradation of organic dye pollutants

Abstract The present study reports the synthesis, characterization, and natural sunlight-driven photocatalytic activity of a novel heterojunction photocatalyst comprised of hierarchical rutile titanium dioxide (r-TiO2) nanostructures and 1T/2H molybdenum disulfide (MoS2)nanosheets. These components were synthesized by solvothermal methods and their effective integration was achieved by using 3- aminopropyltrimethoxysilane as coupling agent. The photocatalytic activity of r-TiO2/MoS2 nanohybrid was explored for the degradation of cationic dye methylene blue (MB), and anionic dye congo red (CR) under natural sunlight. The results reveal that the sunlight-driven photocatalytic activity of pristine r-TiO2 was drastically enhanced upon sensitization with 1T/2H MoS2 nanosheets. The nanohybrid could degrade 99% MB and 98% CR within 150 min with rate constants 25.6×10−3 and 13.2×10−3 min−1respectively. The r-TiO2/MoS2 nanohybrid retained more than 85% of its catalytic activity even after four cycles of reuse. The scavenger test revealed that holes and hydroxyl radicals are mainly responsible for the degradation of MB and CR. The facile synthesis, outstanding catalytic activity under natural sunlight, and excellent recyclability make r-TiO2/MoS2 a promising heterojunction photocatalyst for the degradation of environmental pollutants from wastewater. The present study can provide new insights towards the development of efficient, economical and sustainable photocatalysts for harnessing renewable solar energy for environmental remediation applications.

Photocatalytic degradation of ampicillin antibiotics in aqueous solution utilizing ZnFe2O4/MWCNTs/TiO2 ternary nanocomposite under solar light irradiation

In this study, a novel photocatalyst composed of zinc ferrite (ZnFe₂O₄), titanium dioxide (TiO₂), and multi-walled carbon nanotubes (MWCNTs) was successfully synthesized via the hydrothermal method, and evaluated for the degradation of ampicillin (AMP) in aqueous solutions. The synthesized nanocomposites were thoroughly characterized using various analytical techniques, including XRD, HR-SEM, HR-TEM, EDX, UV-Vis, FT-IR, BET, and XPS analysis. Crystallite sizes of 24.18 nm for ZnFe₂O₄ and 17.8 nm for TiO₂ were determined. The composite exhibited a band gap of 1.4 eV, indicating its enhanced photocatalytic activity. The photocatalytic performance was assessed under varying conditions, including different nanocomposite dosages (0.3–1 g/L), AMP concentrations (10–50 mg/L), and pH values (2–12). The optimal AMP degradation efficiency of 99.2 % was achieved using 0.7 g/L of the photocatalyst, 10 mg/L of AMP, and a pH of 12 under 90 min of solar irradiation. These optimal parameters were then applied to evaluate AMP degradation using ZnFe2O4, TiO2, and ZnFe2O4/MWCNTs individually, with the degradation rate analyzed using a pseudo-first-order model. The superior photocatalytic efficiency can be primarily attributed to improved charge transfer dynamics and effective electron-hole separation, enabled by the doping of MWCNTs. Hydroxyl radicals (OH•) were identified as the primary reactive species responsible for AMP degradation. Furthermore, the catalyst retained 91 % of its photocatalytic efficiency after eight consecutive cycles, demonstrating excellent stability and reusability. These results underscore the potential of the ZnFe₂O₄/MWCNTs/TiO₂ composite as a highly effective and sustainable photocatalyst for removing pharmaceutical pollutants from aquatic environments.

One-Step Construction of Hierarchical Porous and Defect-Rich Zn2+-Doped NH2-MIL-125(Ti) to Enhance Photocatalytic Degradation of Tetracycline Hydrochloride.

The development of efficient metal-organic framework (MOF) photocatalysts for the degradation of tetracycline hydrochloride (TC) is crucial for environmental and public health. Herein, NH2-MIL-125(Ti) flakes (namely, ZnxTi1-x-NML), featuring defect-rich and Zn2+-doping, were synthesized using a one-step solvothermal method. For the first time, the crystal structure of Zn-doped NML was determined by combining extended X-ray absorption with fine structure spectroscopy. The formation mechanisms of the flake morphology with hierarchical porous structures were thoroughly investigated. Compared to NH2-MIL-125(Ti), Zn0.15Ti0.85-NML achieved a 3.4-fold increase in removal of TC under simulated sunlight. The adjusted electronic structure enhances superoxide radical production, coupled with a flake-like and porous architecture that promotes reaction sites, improved mass transfer, and reduced charge distances. Combined with theoretical calculations of the density of states and electrostatic potential, the ligand-metal-metal charge transfer process was elucidated. The possible pathway for the photocatalytic degradation of TC by Zn0.15Ti0.85-NML was further speculated. Moreover, the safety of the photocatalytic pathway was assessed by predicting the toxicity of the degradation intermediates. Our findings link the structure of MOFs to their catalytic efficiency, guiding the creation of sustainable photocatalysts.

Micro-nano bubbles in action: AC/TiO2 hybrid photocatalysts for efficient organic pollutant degradation and antibacterial activity

Developing highly active and sustainable photocatalysts is crucial for environmental remediation. This work focuses on the enhanced photocatalytic degradation efficiency of synthetic dyes using TiO2-coated AC hybrid photocatalysts under MNB aeration. The TiO2-coated AC hybrid photocatalyst (HP) was synthesized via a sol-gel method and characterized using XRD, FTIR, SEM, EDS, HR-TEM, and DRS. The study investigated the photocatalytic degradation of three dyes indigo carmine (IC), reactive black 5 (RB5), and methylene blue (MB) in wastewater, with initial dye concentrations ranging from 10 to 100 μM. Under UVA irradiation, the hybrid photocatalyst with MNB aeration (HP + UVA + MNB) achieved the highest degradation efficiencies of 69.09%, 60.06%, and 55.19% for IC, MB, and RB5, respectively. Further analysis showed that the chromophores and complex structures of these dyes were broken into intermediate products. The Langmuir-Hinshelwood kinetic model was used to describe the reaction mechanisms. The HP + UVA + MNB system demonstrated superior photocatalytic degradation activity, making it suitable for operational and environmental applications in dye wastewater treatment. Additionally, the antibacterial properties of AC and HP were tested at 100 μg/mL, showing effectiveness against both Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli.

Green synthesis of cobalt oxide nanoparticles (Co3O4NPs): Characterization and green light-driven photocatalytic aerobic oxidation of alkyl and aryl sulfides to the corresponding sulfoxides

In recent years, cobalt oxide nanoparticles (Co3O4NPs) have garnered significant attention due to their unique properties and wide range of applications, particularly in catalysis and environmental remediation. This study focuses on the green synthesis of Co3O4NPs using garlic extract as a bio-reducing and stabilizing agent, marking the first instance of employing this eco-friendly and cost-effective method. The synthesized nanoparticles were characterized using various techniques including SEM, EDX, FTIR, XRD, UV–Vis DRS, and BET analysis, revealing their spherical morphology, elemental composition, surface area, and optical properties. The primary application investigated was the photocatalytic aerobic oxidation of alkyl and aryl sulfides to sulfoxides under visible green light irradiation. The study meticulously optimized the reaction conditions, evaluating the effects of different solvents, light sources, and catalyst dosages. The optimal conditions were found to be a MeCN:H2O (5:1) solvent system, green LED light (535 nm), and 10 mg of Co3O4NPs catalyst with the highest TON of 12.5. Under these conditions, the catalyst demonstrated high efficiency, achieving up to 95% yield of sulfoxides with various substrates. Furthermore, the reusability of the Co3O4NPs was assessed through multiple catalytic cycles, showing excellent stability and consistent performance. Mechanistic studies indicated that the photocatalytic activity involves the generation of reactive oxygen species (ROS) such as superoxide anion radicals (O2.-) and singlet oxygen (1O2), with both holes and electrons playing crucial roles in the oxidation process. This research highlights the potential of green synthesized Co3O4NPs as effective and sustainable photocatalysts for selective oxidation reactions, offering a promising approach for environmentally benign chemical processes. The findings pave the way for further exploration of bio-derived catalysts in various industrial applications, promoting greener and more sustainable practices in chemical synthesis.

SnO2QDs: Photophysical properties, photocatalytic activity, mineralization financial cost and recycling process during industrial effluent treatment

This study investigates the synthesis, characterization, and photocatalytic performance of pure and titanium-doped tin dioxide quantum dots (SnO2QDs) prepared via a sonochemical method. The structural and morphological properties were thoroughly examined using XRD, FTIR, SEM-EDX, HRTEM, UV-DRS, and BET surface area analysis. XRD confirmed the formation of tetragonal SnO2 with high phase purity and average crystallite sizes of 2.95 nm for SnO2QD1 (calcined at 270 °C) and 8.36 nm for SnO2QD2 (calcined at 480 °C). Titanium doping was achieved without altering the SnO2 crystalline structure, as evidenced by FTIR spectra showing characteristic vibrational modes and hydroxyl groups. HRTEM images revealed spherical nanoparticles with diameters of 3.2 nm for SnO2QD1 and 9.7 nm for SnO2QD2, supported by SAED patterns confirming their polycrystalline nature. The photocatalytic efficiency was evaluated through the degradation of Reactive Yellow 145 dye under Xenon lamp irradiation. SnO2QD1 exhibited superior photocatalytic activity with a rate constant (k) of 6.94 × 10−3 s−1, achieving 80 % dye degradation in 105 min, compared to SnO2QD2 with a k of 4.50 × 10−3 s−1 and 83 % degradation in 120 min. Titanium doping further enhanced the photocatalytic performance, with SnO2QDT1 (1 % Ti) showing a k of 9.89 × 10−3 s−1 and 80 % degradation in just 90 min, three times more efficient than SnO2QDT2 (9 % Ti). BET analysis indicated a significant reduction in surface area with increased calcination temperature, from 154 m2/g for SnO2QD1 to 86 m2/g for SnO2QD2. The bandgap energies, determined via UV-DRS, were 3.30 eV for SnO2QD1 and 3.34 eV for SnO2QD2, slightly reduced in Ti-doped samples, enhancing visible light absorption. The SnO2QDs demonstrated excellent recyclability, maintaining photocatalytic activity over eight reuse cycles. Economic analysis based on Saudi Arabian electricity tariffs highlighted the cost-effectiveness of SnO2QD1, offering a 5.2 % reduction in energy consumption compared to SnO2QD2. These findings position SnO2QDs as highly efficient and sustainable photocatalysts for industrial wastewater treatment applications.

Development of hydrothermal carbonaceous carbon/NH2-MIL-101(Fe) composite photocatalyst with in-situ production and activation of H2O2 capabilities for effective sterilization

Photocatalytic production of H2O2 has garnered significant attention, but the use of sacrificial reagents in H2O2 photosynthesis and the subsequent limited H2O2 activation efficiency would impede its practical application in water decontamination. In this work, hydrothermal carbonaceous carbon/NH2-MIL-101(Fe) (abbreviated as HTC-cf/NMIL-101(Fe)) heterojunction was fabricated through a solvothermal strategy, and serving as a self-sufficient photo-Fenton-like catalyst to in-situ generate and activate H2O2. Hydrothermal carbonaceous carbon derived from cost-effective waste coffee grounds, serving as a green and sustainable photocatalyst, demonstrated high H2O2 production rate of 612 μmol/g/h without the need for sacrificial reagents or aeration assistance. Moreover, the excellent self-sufficient photo-Fenton activity for HTC-cf/NMIL-101(Fe) can be obtained, which ascribed to the synergistic effect of self-generated H2O2 production as well as the in-situ catalytic H2O2 decomposition of •OH by Fe species in NMIL-101(Fe) and photogenerated electrons. The optimized HTC-cf/NMIL-101(Fe) photocatalyst showed simultaneous improvements in both H2O2 production and activation capabilities. Impressively, the effective circulation of Fe3+/Fe2+ in NMIL-101(Fe), aided by photogenerated electrons, results in a 5-fold increase toward H2O2 decomposition rate constant (Kd) compared to HTC-cf alone under light irradiation in open-air conditions. The enhanced charge separation and appropriate band structure of HTC-cf/NMIL-101(Fe) photocatalyst assured the high selectivity of two-electron O2-reduction to H2O2. HTC-cf/NMIL-101(Fe) displayed excellent photocatalytic sterilization efficiency against E. coli and S. aureus under visible light, and its sterilization application in actual water was also demonstrated. Notably, the adaptability of this system to ambient conditions, including open-air atmosphere, non-sacrificial reagents, and low leaching of Fe ions, highlights the promising practical utility of the HTC-cf/NMIL-101(Fe) photocatalyst.

Efficient photocatalytic degradation of malachite green dye from wastewater using facilely synthesized ternary ZIF-8/Ag/Ag2S nanocomposite: Optimization by RSM (CCD)

The current study compares the photocatalytic potential of zeolitic imidazolate framework-8 (ZIF-8) with ZIF-8 nanocomposites doped with two forms of silver (referred to as AgNPs/ZIF-8 and AgNPs/Ag2S/ZIF-8). Their physicochemical characteristics were evaluated using Fourier-transform infrared, X-ray diffraction, energy-dispersive X-ray, Scanning Electron Microscopy (FESEM), Transmission Electron Microscopy (TEM), diffuse reflectance spectroscopy (DRS), photoluminescence (PL), photocurrent density, Mott-Schottky, and Brunauer Emmett Teller techniques. The photocatalytic activity of the composites was assessed for degradation of malachite green (MG) under visible light irradiation in a solar-based staircase photoreactor for the first time. The optimization of the photodegradation process was achieved by employing central composite design, 0.020 g of AgNPs/ZIF-8 and ZIF-8photocatalyst (in 20 ml of solution), MG Concentration of 7 mg/l, pH of 8, and the irradiation time of 50 min. The predicted model had R2 and R2adj correlation coefficients of 0.987 and 0.975 respectively, which showed experimental results were very close to the predicted values. The results indicated remarkable efficiency in both degradation and mineralization, achieving the degradation rate of up to 98.6 %, a high-rate constant value of 0.0701 min-¹, and an 80 % mineralization efficiency. AgNPs/Ag2S/ZIF-8 exhibited superior photocatalytic performance in comparison to both AgNPs/ZIF-8 and ZIF-8. Different scavengers were used in the experiment and demonstrated that O2− played a crucial role in the photodegradation of MG. Moreover, the nanocomposite AgNPs/Ag2S/ZIF-8 exhibited robust stability and could be repeatedly utilized up to five cycles without notable decline in efficacy, rendering it an environmentally sustainable photocatalyst with promising prospects for industrial utilization.

Threefold enhanced photodegradation of methylene blue using MgO composite with minimum Nd2O3: finding the sweet spot.

Removal of organic dyes like methylene blue (MB) from industrial effluents serves as potential source of potable water. Photocatalytic degradation using sustainable catalyst is deemed to be an affordable solution. In this work, Nd2O3/MgO nanocomposite with different compositions (1, 3, and 5wt% Nd2O3 with MgO) have been achieved using hydrothermal synthesis and characterized extensively. Interestingly, increasing Nd2O3 proportion (1-5%) enhances light absorption, and decreases band gap and electron-hole recombination. The efficacy of the photocatalysts is tested with the degradation of MB dye, through optimizing Nd2O3/MgO proportion, contact time, catalyst dose, and pH. Interestingly, control experiments reveal that 5wt% Nd2O3/MgO achieve 99.6% degradation of MB in 90min at pH 7, compared to 88.8% with bare MgO under same condition. Kinetic data show that 5wt% Nd2O3/MgO exhibits ca. 3 times higher degradation rate compared to MgO. For the first time, our work enable MgO-based sustainable photocatalyst development with minimum (5wt%) rare-earth combination to achieve excellent photocatalytic degradation performance.

Visible light-driven removal of Rhodamine B using indium-doped zinc oxide prepared by sol–gel method

Industrial dye contamination in wastewater poses significant environmental challenges, necessitating the development of efficient photocatalysts for degradation. In this work, we investigate the In doping effect in the photocatalytic activity of zinc oxide (ZnO) nanoparticles for effective RhB degradation. Indium-doped ZnO nanoparticles were synthesized via sol–gel method and x-ray diffraction (XRD) analysis revealed a wurtzite hexagonal structure, with the crystallite size being varying from 65 nm to 53 nm with the introduction of In content. XPS measurements on the 3% In-doped ZnO sample revealed distinct core level spectra for In 3d, Zn 2p, and O 1s regions, confirming the presence of indium, zinc, and oxygen. Brunauer–Emmett–Teller (BET) analysis revealed increased surface area and pore size, with specific surface areas escalating from 0.9 m²/g for pure ZnO to 10.1 m²/g for 3% indium-doped ZnO. Photocatalytic experiments exhibited significant RhB degradation, with degradation efficiencies reaching 93% for 3% indium-doped ZnO under visible light irradiation due to the effect of the presence of In, which causing light absorption enhancement, narrow the band gap and improve charge carrier separation. These findings underscore the potential of indium-doped ZnO nanoparticles as efficient and sustainable photocatalysts for wastewater treatment, offering a promising avenue to address environmental challenges associated with industrial dye-contaminated effluents.Graphical

Sonochemical synthesis, characterization, and infrared-driven photocatalytic performance of 2%Er/x%Yb co-doped BiVO4 nanoparticles (x=2–10%)

This study investigates the influence of Yb co-doping on the photocatalytic performance of 2% Er-doped BiVO4 nanoparticles under infrared light for wastewater treatment. Er/Yb co-doping induces a phase transformation from monoclinic to tetragonal BiVO4, significantly enhancing infrared light absorption and photocatalytic activity. The optimal Yb concentration for maximizing activity is found to be 2%, achieving a one-order-of-magnitude improvement compared to undoped BiVO4. Up-conversion processes involving Yb and Er ions play a crucial role in this enhancement, converting low-energy infrared photons into higher-energy visible emissions that drive photocatalysis. These findings demonstrate a promising strategy for developing highly efficient and sustainable photocatalysts for wastewater treatment utilizing the abundant yet underexplored infrared region of the solar spectrum.

Construction of a Schottky junction for enhanced Cr(VI) photoreduction through partial derivation of NiB from 2D Ni-MOF

Incorporating cocatalysts to form Schottky junctions offers a promising strategy for enhancing photocatalytic performance, particularly in reducing environmental pollutants. This study introduces a novel method utilizing a two-dimensional nickel-based metal-organic framework (Ni-MOF), synthesized via a solvothermal process and partially derived for the decoration of nickel boride (NiB), establishing a Schottky junction photocatalyst. The hierarchically structured Ni-MOF/NiB was synthesized under ambient air conditions with varying molar ratios of NaBH4 (0.8, 1, and 1.2) and employed for Cr(VI) photocatalytic reduction. Among these ratios, the optimal Ni-MOF/NiB-1 exhibited a remarkable photocatalytic efficiency of 96% at pH = 2 under visible light within 75 min. This enhanced performance is attributed to the formation of the Schottky junction between NiB and Ni-MOF, facilitating effective charge carrier migration and separation, as well as the high surface area, numerous active sites, improved visible light absorption, and reduced recombination rate. This effective approach of anchoring a noble metal-free cocatalyst on a porous metal−organic framework creates an economical and sustainable photocatalyst to reduce Cr(VI).

Construction of novel Ce2(WO4)3/rGO nanocomposites for efficient photocatalytic mitigation of antibiotic drug chloramphenicol

In this study, we present the synthesis and characterization of a novel cerium tungstate decorated reduced graphene oxide (Ce2(WO4)3@rGO or CeW@rGO) nanocomposite via a facile hydrothermal method. Comprehensive analyses including XRD, FTIR, SEM, TEM, and XPS were conducted to elucidate the crystal structure, chemical states, morphology, and optical properties of the synthesized nanocomposite. The CeW@rGO exhibited a reduced band gap of 2.14 eV compared to 2.33 eV for CeW, enhancing visible light absorption. Photocatalytic experiments demonstrated the superior efficiency of CeW@rGO, achieving 98.03 % degradation of the antibiotic chloramphenicol (CIP) within 45 min under visible light irradiation. The enhanced photocatalytic performance is attributed to the improved charge separation and extended lifetime of photo-induced charge carriers, facilitated by the rGO. Reactive oxidative species such as O2•− and •OH were identified as key contributors to the degradation process, as confirmed by radical scavenging studies. The plausible degradation mechanism of CIP was proposed based on LC-MS analysis. This work highlights the potential of CeW@rGO as an efficient and sustainable photocatalyst for environmental remediation, offering significant advancements in the field of photocatalytic degradation of organic contaminants. The improved efficiency of the photocatalyst was primarily due to the enlarged surface area and the addition of CeW and rGO to the composite sample. These additions enhance the catalyst's ability to adsorb pollutants and increase the separation of electrons and holes at the interface between two semiconductors by creating an internal electric field. The results toprovide the successfully creation ofCeW/rGO nanocomposites that are cost-effective, highly efficient, lightweight, and sustainable for use in environmental applications.

A Review of Insights into Algae as a Sustainable Bio-based Photocatalyst for Environmental Remediation

Algae have recently emerged as a promising photocatalyst material due to their abundancy, low cost, and environmentally friendly nature. This review summarizes recent progress on utilizing algae as bio-based photocatalysts. Eutrophication and abundance of algae which make it an ideal candidate as a sustainable photocatalyst source, have been discussed. Recent work on synthesis methods such as hydrothermal treatment, calcination, and templating to produce photocatalytically active algae nanoparticles (NPs) has been reviewed. Photocatalytic activity of algae-based materials have been studied such as wastewater treatment, dye removal, and heavy metal remediation. Finally, strategies to further enhance algae's photocatalytic performance, including coating and doping with metals, coupling with graphene, and heterogeneous integration are highlighted here. To wrap up, this review underscores the exciting potential of algae as a sustainable and effective next-generation photocatalytic material.

Experimental Protocols for Sustainable Ammonia Production by Photocatalytic Nitrogen Fixation: Pitfalls and Remedial Measures

AbstractThe synthesis of ammonia (NH3) by photocatalytic nitrogen (N2) fixation has gained tremendous attention from researchers worldwide. The number of reports on different materials for photocatalytic N2 fixation is increasing year by year in the quest for developing breakthrough and sustainable photocatalysts in this field. However, there are several pitfalls (nitrogenous impurities in feed gas and on the surface of the catalyst, reaction conditions, use of scavengers, NH3 quantification methods, etc.) in the path of photocatalytic N2 fixation experiments, which can lead to the reporting of bogus NH3 production rates. Therefore, the use of accurate experimental protocols for the quantification of photogenerated NH3 requires immediate attention and focus of the researchers so that reliable data can be reported in the literature. This perspective article mainly focuses on generating awareness in the photocatalytic N2 fixation research community about the recent establishments for reporting experimental results in this field. Several pitfalls that may lead to the wrong data reporting and remedial measures to avoid them are discussed in detail. Finally, a summary of the recent advancements in this field and recommendations on future directions is provided.

Hydrothermally Synthesized Z-Scheme Nanocomposite of ZIF-9 Modified MXene for Photocatalytic Degradation of 4-Chlorophenol.

4-Chlorophenol (4CP) is a well-known environmental contaminant often detected in wastewater, generally arising from industrial processes such as chemical manufacture, pharmaceutical production, and pesticide formulation. 4CP is a matter of great concern since it is persistent and has the potential to have harmful impacts on both aquatic ecosystems and human health, owing to its hazardous and mutagenic properties. Hence, degradation of 4CP is of utmost significance. This research investigates the photocatalytic degradation of 4CP using a novel Z-scheme heterojunction nanocomposite composed of MXene and ZIF-9. The nanocomposite is synthesized through a two-step hydrothermal method and thoroughly characterized by using XRD, SEM, UV-visible spectroscopy, zeta potential, and electrochemical impedance spectroscopy studies, confirming successful fabrication with improved surface properties. The comparative photocatalytic degradation studies between pristine materials and the nanocomposite were performed, and significant enhancement in performance was observed. The effect of pH on the degradation efficiency is also explored and correlated with the surface charge. The Z-scheme photocatalysis mechanism is proposed, which is supported by time-resolved photoluminescence studies and scavenger experiments. The reusability of the nanocomposite is also evaluated. The study contributes to the development of efficient and sustainable photocatalysts for wastewater treatment.

Enhanced Photocatalytic Degradation of Organic Pollutants Using Iron Lanthanum Oxide Nanoparticles

This study investigates the synthesis, characterization, and photocatalytic performance of iron lanthanum oxide nanoparticles (FeLO NPs) tailored for environmental remediation applications. The nanoparticles were synthesized using a co-precipitation method involving ferrous and lanthanum nitrates, followed by pH adjustment and calcination. Characterization techniques including X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier-transform infrared spectroscopy (FTIR) were employed to analyze the structural and morphological properties of the nanoparticles. XRD confirmed the crystalline nature of FeLO NPs with peaks corresponding to standard indices, while SEM images revealed a heterogeneous surface topology conducive to catalytic activity. FTIR analysis detected functional groups and bonding interactions indicative of the complex molecular composition of the nanoparticles. The Brunauer-Emmett-Teller (BET) method determined a surface area of 2.43 m²/g. Photocatalytic testing using methylene blue (MB) under UV and visible light showed that FeLO NPs achieved up to 90% degradation of the dye, highlighting their effectiveness in pollutant breakdown. The degradation mechanism involved the formation of electron-hole pairs, facilitating radical generation and subsequent pollutant decomposition. This study underscores the potential of FeLO NPs as efficient and sustainable photocatalysts for the treatment of dye-polluted wastewater.

Symbiotic coupling of ZnO nanoparticles and coumarin photosensitizer in soft polyurethane matrices for boosting visible-light photocatalytic performance

Photocatalysis provides a practical and efficient solution to eliminate harmful substances from the environment by using light energy to activate the catalysts, and the development of sustainable photocatalysts easily recoverable and highly efficient in visible light remains a significant challenge. To address this issue, herein we present a facile approach to immobilize silane-functionalized ZnO NPs in polyurethanes with coumarin chromophore, resulting in highly active recyclable and reusable hybrid materials as photocatalytic systems for the degradation of organic dyes. Characterization of ZnO NPs revealed that the attachment of silane units to nanoparticles' surface decreased band gap values (up to 2.83 eV) and reduced the rate of charge carrier recombination. The performed investigations showed that incorporation of ZnO NPs into macromolecular chains via quaternization near to coumarin units promoted efficient photoinduced charge transfer between semiconductor nanoparticles and photosensitizer molecules. The band gap energy for hybrid films ranged between 2.73 eV and 2.32 eV, and the best photodegradation results for malachite green (MG) under visible-light irradiation were attained after 17 min (k = 17.7 × 10−2 min−1). The photocatalytic mechanism was clarified using scavenger tests and the photocatalytic efficiency of the best performing sample was tested for the degradation of other dyes (brilliant blue R, sunset yellow, congo red, rhodamine B, s.o.) and for the removal of MG from binary dye mixtures. The stability and integrity evaluation after 7 catalysis cycles reveals that the photocatalytic potential is retained without substantial structural changes.

Graphitic carbon nitride (g-C3N4) as an emerging photocatalyst for sustainable environmental applications: a comprehensive review

g-C3N4: a sustainable game-changer in photocatalysis. This work explores synthesis, properties, mechanisms, and applications, addresses challenges, and charts future trends.

Insights into interfacial mechanisms: CsPbBr3 nanocrystals as sustainable photocatalysts for primary amine oxidation.

CsPbBr3 nanocrystals (NCs) employed as a photocatalyst resulted in efficient benzylamine oxidation under oxygen atmosphere. Improved reaction yields stem from favorable -NH2 functional group interactions on the NC surface, while additional interactions with -OMe or -SMe functional groups post-product formation result in lower yields. These insights into interfacial interactions and mechanistic aspects advance sustainable chemical transformations through cost-effective and recyclable CsPbBr3 NC-catalyzed primary amine oxidation.