Excellent Photocatalytic Efficiency Research Articles

Bio-fabrication of tin oxide (SnO2) nanoparticles Capped with rosmarinic acid in Argument with antimicrobial activity and photocatalytic degradation

This investigation emphasizes the green synthesis and economical method of SnO2-NPs using crude rosmarinic extract via ultrasonic-assisted extraction methodology. The leaf extract acts as an excellent reducing, capping, and stabilizing agent for SnO2 preparation. The morphology, elemental conformation, crystallinity, size and functional groups responsible for surface stabilization and capping of as-synthesized SnO2 nanoparticles, were characterized. UV absorption showed absorption peak of 200 nm with energy band gap of 2.23 eV and the functional groups recorded in the range of 400 to 4000 cm−1 defined SnO2 formation. The crystalline nature was confirmed via XRD, and both the element peaks (Sn and O) are observed through EDX analysis. The irregular spherical shapes of 6–18 nm are evaluated via TEM and SEM. SAED confirmed the nanocrystalline nature. The green synthesized SnO2 nanocomposite demonstrated excellent methylene blue photocatalytic efficiency, and the subsequent potential mechanism was proposed. Utilizing this nanocomposite, nearly 89.79 % of Methylene Blue was removed in 80 mins under direct sunlight, documenting it as an efficient photocatalyst. Furthermore, the nanocomposite demonstrated comparable antimicrobial activity towards Escherichia coli and Klebsiella pneumonia, illustrating the effectiveness of the nanocomposite. Consequently, the current work explains the significant synthesis of SnO2 nanoparticles and demonstrates their potential photocatalytic and antibacterial properties.

Innovative synthesis of ternary heterojunction CuInS2/BiOI/Bi2MoO6 for 2,4-DCP degradation and its dechlorination performance

This study focuses on a novel ternary heterojunction catalyst for the removal of 2,4-dichlorophenol (2,4-DCP), an organic pollutant that is difficult to degrade. An efficient CuInS2/BiOI/Bi2MoO6 ternary heterojunction photocatalyst was formed by constructing a CuInS2/BiOI composite layer on a Bi2MoO6 substrate using an in-situ growth technique. The microstructure and photoelectric conversion properties of the catalysts were comprehensively resolved by systematic material characterization, including scanning electron microscopy (SEM) observation, X-ray photoelectron spectroscopy (XPS) analysis and photoelectrochemical testing. The experimental results showed that the optimized catalyst at a loading of 2.0 g/L exhibited excellent photocatalytic degradation efficiency against 20 mg/L concentration of 2,4-DCP at neutral pH, reaching 80.3 % degradation rate in 120 min. This high performance was mainly attributed to the enhanced charge-carrier separation mechanism at the heterojunction interface, which effectively enhanced the utilization and transfer rate of photogenerated electron-hole pairs and enhanced the photocatalytic activity of the catalyst. In addition, the study also deeply explored the conversion pathway of elemental chlorine in the photocatalytic system, elucidated the mechanism of 2,4-DCP degradation and dechlorination, and provided a theoretical basis for further improving the environmental adaptability and dechlorination efficiency of the catalyst. Overall, the CuInS2/BiOI/Bi2MoO6 ternary heterojunction photocatalysts proposed in this study demonstrate a broad application prospect in the purification of 2,4-DCP and other organic pollutants, and open up a new way to solve the problems of industrial wastewater treatment, which is of great environmental significance and scientific value.

Bio-inspired fabrication of Ag-ZnO nanoparticle decorated Nylon 11 nanofibers: Multifunctional membrane for environmental remediation

Traditional wastewater treatment methods using nanoparticles encounter challenges with catalyst recovery. In this study, we fabricated a Nylon 11 nanofibrous membrane (NFM) via electrospinning and functionalized it with polydopamine to immobilize Ag-ZnO nanoparticles for photocatalytic degradation of organic pollutants. The Nylon 11 NFM was treated with a dopamine tris buffer solution for polydopamine (PDA) coating, which facilitated mussel-inspired attachment of the ZnO nanoparticles. These nanoparticles served as a nucleation site for the biomimetic nucleation of Ag-ZnONPs during the hydrothermal process. The synthesized composite membrane was characterized by various microscopic and spectroscopic techniques. The water contact angle decreased from 135° (Nylon 11 NFM) to 41° (PDA/Nylon 11 NFM) and the filtration efficiency improved 10 folds (from 15.92 Lm-2 hr-1 to 170.60 Lm-2hr-1) at ambient conditions. The Ag-ZnO/PDA/Nylon 11 NFM showed strong antimicrobial activity against different bacterial strains and excellent photocatalytic degradation for methyl orange with a rate constant of 0.0431 min-1, significantly surpassing other configurations. The membrane exhibited excellent stability, reusability and consistent photocatalytic efficiency over multiple cycles. It is easily recoverable from the reaction mixture, and suitable for repeated use, making it a promising candidate for environmental remediation due to its antibacterial properties, photocatalytic activity, enhanced filtration efficiency, and reusability.

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.

Rigid covalent organic frameworks with thiazole linkage to boost oxygen activation for photocatalytic water purification

Owing to their capability to produce reactive oxygen species (ROS) under solar irradiation, covalent organic frameworks (COFs) with pre-designable structure and unique architectures show great potentials for water purification. However, the sluggish charge separation, inefficient oxygen activation and poor structure stability in COFs restrict their practical applications to decontaminate water. Herein, via a facile one-pot synthetic strategy, we show the direct conversion of reversible imine linkage into rigid thiazole linkage can adjust the π-conjugation and local charge polarization of skeleton to boost the exciton dissociation on COFs. The rigid linkage can also improve the robustness of skeleton and the stability of COFs during the consecutive utilization process. More importantly, the thiazole linkage in COFs with optimal C 2p states (COF-S) effectively increases the activities of neighboring benzene unit to directly modulate the O2-adsorption energy barrier and improve the ROS production efficiency, resulting in the excellent photocatalytic degradation efficiency of seven toxic emerging contaminants (e.g. degrading ~99% of 5 mg L−1 paracetamol in only 7 min) and effective bacterial/algal inactivation performance. Besides, COF-S can be immobilized in continuous-flow reactor and in enlarged reactor to efficiently eliminate pollutants under natural sunlight irradiation, demonstrating the feasibility for practical application.

Exfoliated g-C3N4-CdS-MXene an efficient all-solid-state Z-type heterojunction serving as efficient photo/electro/photoeletro catalyst for oxygen evolution reaction and dye degradation under visible light at low bias voltage

The rational design of highly active catalysts for the photo/electro/photoelectro catalytic O2 evolution reaction (OER) and water treatment plays a crucial role in the development of sustainable energy generation and environment remediation technologies. Catalysts which are effective in solar light at a low external bias potential are in great demand. Herein, a novel catalyst consisting of all-solid-state Z-scheme g-C3N4-CdS-MXene heterojunction has been designed for photo/electro/photoelectro catalytic reactions. g-C3N4-CdS-MXene exhibited excellent photocatalytic efficiency towards Methylene Blue degradation under simulated solar light irradiation and superb electrocatalytic and photoelectron catalytic efficiency for OER. This catalyst showed high OER performance with an early onset potential of 1.58 V, a low overpotential of 350 mV (at 10 mA cm−2), and low value of Tafel slope (98 mV dec−1). When OER was combined with the photoelectro catalytic reaction for Methylene Blue degradation, g-C3N4-CdS-MXene demonstrated an exceptional photoelectro catalytic performance by degrading 100 % Methylene Blue within 4 min under solar light irradiation at a very low bias of 350 mV. This catalyst also exhibited its capability to degrade various dyes used in textile industries. This work provides an interesting strategy for simultaneous O2 production and efficient dye degradation for environmental and energy engineering.

Visible-light-driven Bi2WO6/biochar composite photocatalyst efficiently degrades 17α-ethinylestradiol (EE2) and 17β-estradiol (E2) under persulfate synergy

Biochar (BC) composite photocatalysts have attracted much attention by virtue of their high efficiency in removing endocrine disruptors (EDCs). However, there has been a lack of systematic research on the mechanism and constitutive relationship of BC on photocatalysts, which has seriously impeded the development process in this field. In this study, Bi2WO6–BC2% composite photocatalysts were prepared by microwave-assisted hydrothermal method and used for degradation of 17α-ethinylestradiol (EE2) and 17β-estradiol (E2) in conjunction with persulfate synergy (PS). The removal rate of EE2 and E2 by Bi2WO6–BC2% was as high as 99.41 % (12 min) and 97.84 % (15 min), respectively. Systematic studies have shown that BC enhances the catalytic activity mainly through the following ways, increasing the specific surface area of the photocatalytic system, enriching the types of functional groups, enhancing the separation ability of photogenerated electron–hole pairs, and promoting the concentration of active free radicals. The results of the phytotoxicity experiments showed that compared to the EE2 or E2 pollutant solutions, the stem and root lengths of V. radiata increased by 93.63 % and 389.58 % in EE2 metabolites, and by 117.35 % and 160.38 % in E2 metabolites. Similarly, the stem and root lengths of P. vulgaris increased by 80.08 % and 174.91 % in EE2 metabolites, and by 188.92 % and 345.75 % in E2 metabolites. This work not only fills the gap in the study of the mechanism of action of BC, but also provides a green catalyst with very excellent photocatalytic efficiency and detoxification properties.

Production of magnetic photocatalysts from TiO2, Fe(NO3)3 and sucrose and their application for the degradation of model organic contaminants

AbstractBACKGROUNDPhotocatalysis is an efficient method for the removal of organic contaminants in wastewater. In this study, different magnetic photocatalysts for the degradation of organic compounds were prepared.RESULTSTi/C/Fe photocatalysts were prepared by supporting TiO2 (20, 40 and 60% w/w) on a carbon/iron oxide (C/Fe) magnetic carrier. Characterization via Raman spectroscopy, X‐ray diffractometry, thermal analysis, X‐ray fluorescence, scanning electron microscopy and energy‐dispersive X‐ray spectroscopy/elemental mapping and magnetic property analysis by vibrating‐sample magnetometry confirmed the presence of TiO2, Fe3O4, Fe3C and char in the photocatalysts as well as their magnetic properties. The results of specific surface area analysis showed that the C/Fe support had a surface area of 183 m2 g−1 and that this area decreased with an increasing amount of supported TiO2, reaching up to 129 m2 g−1. Diffuse reflectance spectroscopy characterization revealed that the bandgap values obtained for the photocatalysts (Ti/C/Fe) were lower than 3.2 eV. The prepared photocatalysts showed high efficiency in degrading the contaminants Remazol Black (RB5) (99%), paracetamol (77%) and phenol (90%). Recovery and reuse experiments using RB5 showed that after the fourth reaction, the photocatalytic efficiency was reduced by 50%, and the recovery reached up to 70%. Sedimentation kinetics showed that while only 6% of the TiO2 was deposited, up to 89% of the photocatalysts were deposited.CONCLUSIONSThese results indicate that the photocatalysts showed excellent photocatalytic efficiency for different contaminants and can be easily and quickly separated from the reaction medium by magnetic separation. © 2024 Society of Chemical Industry (SCI).

Enhanced photocatalytic performance of NiFe2O4/ZnIn2S4 p-n heterojunction for efficient degradation of tetracycline

The persistent release of tetracycline into the environment significantly endangers both ecosystems and human health. Zinc indium sulfide (ZnIn2S4) capable to degrade tetracycline pollutants under visible light irradiation has attracted extensive attentions and great effort has been devoted to augment its catalytic efficacy. In this work, we synthesized a p-n heterojunction, NiFe2O4/ZnIn2S4, to enhance the carrier migration rate and explained the intrinsic mechanism by density functional theory. When the heterojunction was formed, carriers traversed from the n-type NiFe2O4 to the p-type ZnIn2S4, instigating the emergence of a built-in electric field to facilitate the separation of carriers. 2 %-NiFe2O4/ZnIn2S4 exhibited excellent photocatalytic efficiency in tetracycline (TC) degradation and total organic carbon (TOC) removal. Compared to pure ZnIn2S4 and NiFe2O4, the TC degradation rates of 2 %-NiFe2O4/ZnIn2S4 were 2.0 times and 16.9 times higher, respectively. Additionally, 2 %-NiFe2O4/ZnIn2S4 had a saturation magnetization intensity of 3.05 emu/g, allowing for rapid recovery of the catalyst under a magnetic field. Superoxide radicals (O2−) and holes (h+) were the primary active species driving the degradation process. Furthermore, potential reaction pathways of tetracycline in this photocatalytic process were determined and bioconcentration factor and developmental toxicity of the intermediate products were accessed. This work held great potentials for wastewater treatment and provided a pathway for the development of magnetic recyclable photocatalysts.

Solar Light-Driven Molecular Oxygen Activation by BiOCl Nanosheets: Synergy of Coexposed {001}, {110} Facets and Oxygen Vacancies.

Single-crystalline BiOCl nanosheets with coexposed {001} and {110} facets, as well as oxygen vacancies, were synthesized using a simple method. These nanosheets have the ability to activate molecular oxygen, producing reactive superoxide radicals (77.8%) and singlet oxygen (22.2%) when exposed to solar light. The BiOCl demonstrated excellent photocatalytic efficiency in producing H2O2 under simulated solar light and in oxidatively hydroxylating phenylboronic acid under blue LED light. Our research highlights the significance of constructing coexposed {001} and {110} facets, as well as oxygen vacancies, in enhancing photocatalytic performance. The BiOCl nanosheets have the capability to produce H2O2 with a solar-to-chemical energy conversion efficiency of 0.11%.

Construction of MoS2/BN nanohybrids with enhanced photocatalytic performance for RhB and TC degradation

In this study, MoS2/boron nitride nanohybrids have been fabricated via a simple hydrothermal process. Highly efficient nanohybrids have been synthesized by adding boron nitride (BN) as interfacial charge carrier migrate mediators onto the MoS2. The MoS2/BN nanohybrids exhibit excellent photocatalytic efficiency for removing rhodamine B (RhB) and tetracycline (TC) pollutants. The MoS2/BN nanohybrids show the best rate constant of 0.07 min−1, which is 1.5 folds greater than MoS2. Besides, MoS2/BN nanohybrids exhibit excellent cycling stability. The conformable improved mechanism for MoS2/BN-10 % nanohybrids could be assigned to the useful interfacial charge carrier separation and transfer between MoS2 and BN. The investigative results exhibited that the heterostructures presented better photocatalytic performance than the bare MoS2, and a slight proportion of the BN sample was favorable for photoinduced electron-hole pairs separation, which can improve the photocatalytic efficiency of MoS2/BN nanohybrids. This study displayed a facile process for the reasonable design of photocatalysts by developing their heterostructure and application.

RECENT PROGRESS IN THE SYNTHESIS AND PHOTOCATALYTIC DEGRADATION OF ORGANIC POLLUTANTS BY GRAPHENE-BASED TiO2 NANOCOMPOSITE: A REVIEW

Numerous sustainable water processing techniques have been widely investigated and are capable of boosting the quality of water. Among these techniques, photonanocatalysis has stood tall with great promises in the last few decades. Nonetheless, a major challenge in the environmental remediation of photocatalyst technology is to develop an ideal photocatalyst that must have excellent photocatalytic efficiency, large specific surface area, maximum harvesting of solar energy, high durability and recyclability. Due to their stability, low toxicity, low cost and superhydrophilicity TiO2 has been used by researchers as an efficient photocatalyst for the degradation of organic pollutants. Unfortunately, it suffers greatly due to its high band gap with 3.2[Formula: see text]eV, insufficient visible light response, fast photogenerated electrons and holes recombination rate and serious agglomeration. Keeping these views, the present review highlights the principal results of studies on current practical synthesis and photocatalytic activity of graphene-based TiO2 nanocomposite materials for the treatment of water. The amalgamation of graphene oxide (GO) and reduced graphene oxide (rGO) with nanoscale TiO2 particles results in synergistic properties thereby tuning and increasing the functionality of the composite. In this regard, the review also addressed the progress and insight into graphene-based TiO2 nanocomposite in photocatalytic removal of organic pollutants including basis mechanism, possible key strategies of the composite, and an overview of how to elevate efficacy. Finally, brief challenges and future perspectives in this field are also presented. Indeed, this work illustrated that graphene-based TiO2 composite nanomaterials can be a green signal in the future of photocatalysis targeting water pollution remediation.

Selenium doping to improve internal electric field for excellent photocatalytic efficiency of g-C3N4 nanosheets

Graphitic carbon nitride is a promising photocatalyst to address environmental issues and energy applications. Herein, we develop an efficient defect-containing functionalized system of 2D selenium doped g-C3N4 porous nanosheets via one pot with two-step temperature for the first time. During heat treatment, Se-infused g-C3N4 nanosheets loosen stacking and form thinner nanosheets, which could effectively shorten the electronic path of charge migration. The introduction of nitrogen vacancies creates a midgap energy state below the CB, which improves the light-harvesting efficiency. Moreover, the dual effect of N vacancy and Se doping provides a driving force for the dissociation of excitons and achieves an effective spatial charge separation. High specific surface area (104.1 m2/g), suitable bandgap (2.65 eV), and good photocurrent response (0.45 µA cm−2) help to enhance the photocatalytic efficiency of 1-SeCN remarkably. Henceforth, high photocatalytic H2 production rate of 5441 µmol g−1 h−1 and CO evolution rate of 31.5 µmol g−1 h−1 verifies the effective Se doping enhances the photocatalytic efficiency of g-C3N4. Furthermore, DFT calculations are consistent with experimental results and this facile engineering strategy provides a scalable way to develop a novel, efficient g-C3N4-based photocatalyst for H2 production and CO2 reduction.

CdS@NiCr-LDH Z-scheme heterojunction with high adsorption–photocatalysis for uranium(VI) removal without any sacrificial agent

The use of photocatalysis for the removal of U(VI) has the advantages of being green, eco-friendly and sustainable. It is common practice to enhance the photocatalytic activity of photocatalysts by adding sacrificial agents, however, this is uneconomical and contrary to the vision of carbon neutrality and carbon peak in the world. Herein, we fabricate a Z-scheme heterojunction for the photocatalytic removal of uranium (VI) based on CdS nanorods@NiCr layered double hydroxide (CdS@NiCr-LDH). Excellent photocatalytic efficiencies and removals were achieved under visible light irradiation without any sacrificial agent. The optimum uranium(VI) removal rate of CdS@NiCr-LDH was 0.057 min‐1, which was 6.3 and 5.0 times higher than that of CdS and NiCr-LDH, respectively. In particular, the U(VI) removal amount over CdS@NiCr-LDH reached 2246.14 mg g−1. The CdS@NiCr-LDH heterojunction creates a narrower energy band gap (Eg = 2.06 eV), which is more favorable for visible light absorption, according to UV–vis DRS results. According to ESR and DFT calculations, possesses an intrinsic electric field between NiCr-LDH and CdS composite that efficiently prevents electron-hole complexation, resulting in highly efficient removal of U(VI) under visible light irradiation without the need of sacrificial agents. This work lays the foundation for research on photocatalytic U(VI) treatment by CdS@NiCr-LDH in wastewater.

Accelerated photodegradation of T-2 toxin over magnetic recyclable ZnO/CaFe2O4 nanocomposite with a p-n based Z-scheme heterojunction architecture

T-2 toxin (T-2), one of the most toxic mycotoxins, has drawn extensive attention due to its universality and persistence in food and the environment. In this study, a novel magnetic ZnO/CaFe2O4 nanocomposite with a p-n based Z-scheme heterojunction was successfully constructed by a hydrothermal method for efficient photodegradation of T-2 toxin. The optimal cubic structure of ZnO/CaFe2O4 endows it with excellent photocatalytic efficiency in removing T-2 toxin, such that near-total degradation was achieved with an exceptionally high mineralization value (64 %) after 180 min of UV radiation. This efficacy was attributed not only to the abundant reaction sites on the binary composites, but also its Z-scheme heterojunction promoting the electron-hole (e−-h+) separation and hence favors redox processes. The OH played a major role in the photodegradation, and the decomposition pathway of T-2 was proposed based on the results of UHPLC-Q-TOF-MS/MS data and density functional theory (DFT) calculations. This work provided a green approach for removing the refractory natural pollutants.

Efficient visible light-driven photodegradation of glyphosate utilizing Bi2WO6 with oxygen vacancies: Performance, mechanism, and toxicity assessment

Global environmental deterioration poses a major risk to ecological security and human health, and emerging technologies are urgently needed to deal with it. Therefore, the exploitation of photocatalysts with favorable activity for efficient degradation of pesticide contaminants is one of the strategies to achieve environmental remediation. Herein, oxygen vacancy-rich Bi2WO6 (Ov-BWO) was prepared through a solvothermal method utilizing ethylene glycol (EG), which exhibited excellent photocatalytic efficiency in photodegradation of glyphosate. The formation of oxygen vacancies (Ovs) in Ov-BWO was demonstrated utilizing XPS and EPR. PL, TRPL, photocurrent tests, and EIS analyses revealed that Ovs accelerated effective transfer of photogenerated charge, extended lifetime of charge carriers, promoted production of active species and significantly improved the photocatalytic performance. Compared with the low-activity Bi2WO6 (BWO, 59.6%), Ov-BWO showed outstanding photocatalytic activity, achieving a degradation efficiency of 91% for glyphosate at 120 min of visible light irradiation. Moreover, Ov-BWO also displayed outstanding recyclable stability after four repeated uses. Based on the characterization of photoelectric properties, a feasible photocatalytic reaction was put forth, along with glyphosate degradation pathways. Furthermore, the degradation intermediates of glyphosate were analyzed in detail employing HPLC-MS. The toxicity assessment indicated that degraded products had been proven to be non-toxic to the ecological system. This work presents the potential of photocatalysts with Ovs for the photodegradation of pesticides, providing a viable strategy for environmental renovation.

Bi4O7 modified AgBiO3 to construct Z-scheme heterojunction for photocatalytic removing phenol

The Z-scheme heterojunction Bi4O7/AgBiO3 photocatalysts were synthesized by hydrothermal method. It exhibited excellent photocatalytic degradation efficiency (74.87%) for phenol, which is 2.6 and 4.5 times more efficient than pure AgBiO3 and Bi4O7, respectively. The improvement of photocatalytic performance can be ascribed the enhanced photo-induced charge separation efficiency of the Z-scheme heterostructure through various characterization analysis and experiment tests. In addition, the effective degradation of other organic pollutants like bisphenol A, tetracycline and ciprofloxacin of Bi4O7/AgBiO3 was also confirmed. This study provides a reference for designing photocatalysts that can degrade organic pollutants efficiently.

Photocatalytic efficient cleavage of C-C bond in lignin model using water as solvent

Photocatalytic lignin C-C bond (LCCD) cleavage is one possible strategy to promote high-value utilization of lignin. However, it still confronts many difficulties due to the stability of the lignin structure and the high activation energy of LCCD. Herein, a graphitic carbon nitride photocatalyst with the introduction of cyano groups and K+ ions (6MCN) is synthesized. Compared with pure carbon nitride (PCN), 6MCN exhibits superior photogenerated carrier separation ability, excellent sunlight capture ability, and greater oxidation capability. Under simulated sunlight, 6MCN significantly improves the photocatalytic efficiency of LCCD breakage in β-1 lignin models and aromatic vicinal diols (ACD), compared with earlier literature. The improved Cβ radical mechanism and single-electron transfer (SET) pathway are the primary mechanisms in the photocatalytic reaction. Hydroxyl radicals, superoxide radicals, and photogenerated holes are all involved in the photocatalytic cleavage of LCCD. However, hydroxyl radicals, as the most important active radicals, not only trigger the SET mechanism and Cβ radical mechanism but also provide the O and H atoms required for photocatalytic fracture of LCCD, which is very critical to obtain excellent photocatalytic efficiency. This work offers new insights into the photocatalytic breakage of LCCD in β-1 lignin models and ACD through the development of high-performance photocatalysts and the control of radical types.

Schottky-Functionalized Type-II heterojunction of Ag/CuNb2O6/g-C3N4: Efficient photoredox capability of CO2 to valuable fuel products via gas phase adsorption

Owing to encyclopedic energy crises and ecological concerns, the conversion of solar energy into sustainable value-added fuel products using a reasonable photocatalyst has received a lot of interest. The crucial challenge of the photoreduction of CO2 into fuel products such as CO and CH4 is the minor output and poor selectivity. Herein, a novel synthesized schottky-functionalized type-II heterojunction, Ag/CuNb2O6/g-C3N4 (Ag/CNO/g-CN), is extensively characterized to provide insights regarding its photocatalytic performance in reducing CO2. More significantly, electron paramagnetic resonance was employed to assist in understanding the inclusion of Schottky-junction and type II heterojunction charge transfer. The CO2 photoreduction to CO (2.78 μmol g−1h−1) with Ag/CNO/g-CN was 5- and 3-fold higher than single CNO and single g-CN, and the CO2 photoreduction to CH4 was 0.15 μmol g−1h−1 under simulated solar irradiation. This enhanced CO2 photoreduction was attributed to the large surface area and type II heterojunction, which promoted the separation as well as the transformation of photoinduced e−/h+ pairs and the superior redox ability of charge carriers. The composite's excellent photocatalytic efficiency towards CO2 was exceptionally enhanced by depositing Ag on CNO/g-CN. This study paves the way for immediate needs to explore the selective conversion of CO2 into CO and CH4 via systematic designing and effective schottky-functionalized type-II heterojunction.

Distinguishable photorecycling of PVDF nanocomposites membrane for reactive yellow 145 dye and real industrial wastewater treatment by different photocatalytic processes

This paper investigates the photocatalytic performance and recyclability of PVDF-MWCNTs-TiO2 nanocomposite membranes for the treatment of textile wastewater under sunlight irradiation. The nanocomposites were fabricated by incorporating varying weight ratios of MWCNTs-TiO2 (1 %, 3 %, 6 %, and 9 %) into PVDF matrices using a solvent casting method. Optimal loading of MWCNTs-TiO2 at 9 wt% resulted in nanocomposites with enhanced surface area (94.15 m2/g), reduced band gap (2.38 eV), uniform dispersion of nanoparticles, and abundant surface hydroxyl groups. Under Xenon lamp irradiation, the optimized PVDF-9 %(MWCNTs-9 %TiO2) nanocomposite achieved a high apparent reaction rate constant (kapp) of 9.92 × 10−3 s−1 for photocatalytic degradation of the model dye Reactive Yellow 145. Significantly, when tested on-site at a Saudi Arabian textile facility over 6 months, this nanocomposite effectively reduced the chemical oxygen demand (COD) of real wastewater samples to regulatory limits of 1000 ppm under natural sunlight irradiation. The COD values were lowered from an initial 5050–6200 ppm to a final range of 785–945 ppm using the PVDF-9 %(MWCNTs-9 %TiO2) membrane. Furthermore, the optimized nanocomposite exhibited good recyclability, retaining around 87 % of its initial activity after 8 reuse cycles for industrial wastewater treatment. The excellent photocatalytic efficiency and reusability of the MWCNTs-TiO2 modified PVDF nanocomposite under solar irradiation highlight its promise as a sustainable membrane technology for environmental remediation.