Photocatalytic Effect Research Articles

Titania stabilized Pickering emulsion for photocatalytic degradation of o-xylene

Efficient removal of insoluble volatile organic compounds (VOCs) from wastewater is a significant environmental challenge. In this work, we exploit the synergistic effect of photocatalysis and the high interfacial area of TiO2-stabilized Pickering emulsion to achieve efficient degradation of o-xylene, typically present in wastewater discharged from many industries. Interfacial photocatalysis is carried out by considering o-xylene in water Pickering emulsions stabilized by commercial titania nanoparticles in a multitube non-stirred reactor setup. Stable emulsions used for catalysis are formulated by optimizing o-xylene volume fraction, TiO2 concentration, pH, and homogenization conditions. The influence of photocatalyst loading, emulsion droplet size, and reaction conditions are systematically examined to determine their influence on the rate of photocatalytic degradation of o-xylene. Due to enhanced photocatalytic activity compared with conventional stirred batch photocatalysis, the TiO2-stabilized Pickering emulsion is found to increase the degradation rate and removal efficiency of o-xylene significantly. Furthermore, the Pickering emulsion stability during the photocatalytic process is studied, demonstrating the capacity of the emulsions to maintain stability and catalytic activity over a longer time period. The distinctive characteristics of Pickering emulsions – excellent storage stability and enhanced photocatalytic activity – make them a promising option for advanced wastewater treatment. The findings lead to the development of ecologically acceptable and sustainable VOC degrading strategies, which might be used in industrial and home wastewater treatment systems.

Antifouling characteristics and mechanisms in visible-light photocatalytic membrane bioreactor based on g-C3N4 modified membrane

A novel visible-light photocatalytic membrane bioreactor (R3) was constructed for membrane fouling control and effluent quality improvement. Specially, g-C3N4 modified membrane was evaluated for the performance of synergistic separation and photocatalysis. Another two parallel reactors, MBRs with ceramic membrane (R1) and g-C3N4 membrane in dark condition (R2), were operated synchronously for comparison. A satisfactory effluent quality was obtained in R3 with COD and NH4+-N around 22.0 mg/L and 1.02 mg/L during 60-day operation, which was superior to R1 (27.8, 1.42 mg/L) and R2 (29.9, 2.26 mg/L). The thickness of cake layer on membranes in R3 (2.46 μm) was thinner than R1 (3.52 μm) and R2 (4.97 μm) after operation, indicating the introduction of visible light could effectively mitigate membranes fouling. Moreover, microorganism community analysis revealed that visible light increased the relative abundance of Bacteroidetes and Chryseolinea, which not only enhanced the activity of microorganisms in metabolizing organic nutrients, but also improved the transfer and utilization of photogenerated electrons on the semiconductor-microorganism interface. The active aromatic protein metabolism and the upregulated related enzymes further demonstrated the synergistic effect of photocatalysis and microbial communities on the membrane fouling mitigation. This work provides a novel application of photocatalysis into antibiofouling effect in MBRs, and opens a strategy for bacteria inactivation and foulants removal with eco-friendly solar energy.

Photocatalytic Bleaching Process of Cotton Fabric with H2O2 and H2O2 /n-TiO2

This study delves into the exploration of an alternative bleaching method as a substitute for hydrogen peroxide, addressing concerns related to its excessive chemical usage, high waste load, and elevated energy and water consumption. Photocatalytic bleaching was implemented on 100% cotton fabrics. Initially, hydrogen peroxide served as a catalyst, and the photocatalytic effect was meticulously examined. Subsequently, nano-sized TiO2 was introduced into the photocatalytic recipe, and operational conditions were fine-tuned to determine the optimal bleaching process for cotton fabrics. All photocatalytic experiments were systematically compared with conventional hydrojen peroxide bleaching method. A comprehensive analysis, encompassing color spectrum values, SEM, SEM-EDX, XRD, and FTIR-ATR tests, was conducted. The results revealed a notable 13.36% enhancement in whiteness performance during bleaching when subjected to photocatalytic treatment with nano TiO2 and H2O2 in tandem. This study posits itself as an environmentally conscious alternative to the long-standing conventional bleaching processes prevalent in the textile industry.

Effects of Titanium Dioxide (TiO2) on Physico-Chemical Properties of Low-Density Polyethylene.

Hazardous chemicals are transported on rail and road networks. In the case of accidental spillage or terror attack, civilian and military first responders must approach the scene equipped with appropriate personal protective equipment. The plausible manufacturing of chemical protective polymer material, from photocatalyst anatase titanium dioxide (TiO2) doped low-density polyethylene (LDPE), for cost-effective durable lightweight protective garments against toxic chemicals such as 2-chloroethyl ethyl sulphide (CEES) was investigated. The photocatalytic effects on the physico-chemical properties, before and after ultraviolet (UV) light exposure were evaluated. TiO2 (0, 5, 10, 15% wt) doped LDPE films were extruded and characterized by SEM-EDX, TEM, tensile tester, DSC-TGA and permeation studies before and after exposure to UV light, respectively. Results revealed that tensile strength and thermal analysis showed an increasing shift, whilst CEES permeation times responded oppositely with a significant decrease from 127 min to 84 min due to the degradation of the polymer matrix for neat LDPE, before and after UV exposure. The TiO2-doped films showed an increasing shift in results obtained for physical properties as the doping concentration increased, before and after UV exposure. Relating to chemical properties, the trend was the inverse of the physical properties. The 15% TiO2-doped film showed improved permeation times only when the photocatalytic TiO2 was activated. However, 5% TiO2-doped film exceptionally maintained better permeation times before and after UV exposure demonstrating better resistance against CEES permeation.

Molybdenum Disulfide–Zinc Oxide Mixed Phase Network as Water Purifier

AbstractThe present work reports the development of oxide‐sulfide hybrid by simple hydrothermal process where zinc oxide (ZnO) prepared by simple chemical process is added in situ during the growth of molybdenum disulfide (MoS2) by hydrothermal process. The as prepared sample is characterized by X‐ray diffraction (XRD), field emission scanning electron microscope (FESEM), and energy dispersive X‐ray analysis (EDX). XRD confirms the coexistence of both ZnO and MoS2 in the sample whereas FESEM shows that fractal kind of sulfide structures get developed over ZnO rod. EDX carries the information regarding the stoichiometry of the sample. The sample is proven to be an excellent remover of textile dyes by synergistic effect of photocatalysis and adsorption with almost 100% efficiency following simple first‐order reaction kinetics. When the porous structure of the sample helps the process of adsorption, the charge transfer mechanism has been assumed to be responsible for photocatalytic dye degradation. The latter involves the transferring of electrons or holes between the photocatalyst and the dye molecules, leading to the generation of reactive species that initiate the degradation process. The combined effect of these two processes takes only 30 min to degrade textile dyes like Bengal rose (BR) and methylene blue (MB). Thus, the present work is supposed to serve as milestone in the associated field.

Biocompatible 2D SnSe Nanoflake Employed Enhanced Photocatalytic Degradation of Rhodamine B

AbstractIn this article, we report the results of the photocatalytic effect of the cost effective grown SnSe nanoparticles (NPs), nanoflakes (NFs), nanoflowers (NFLs) on the toxic water contaminant dye of Rhodamine B (RhB) under visible light irradiation different duration time. The results showed that for the degradation of 99 %, 96 % and 94 % of the RhB have been occurred in presence of NFs, NFLs, NPs, respectively for the irradiation time of 30 min, 45 min, 65 min, respectively. Before photocatalytic test, the grown SnSe were characterised optically and structurally. The nanoparticles, nano flakes, nanoflowers morphology along with atomic composition of Sn and Se were observed from FESEM images and EDAX analysis. The direct band gap of the NPs, NFs, NFLs was calculated from UV‐VIS spectrum and found to be 1.89 eV, 1.78 eV, 1.7 eV, respectively. The crystal structure showed orthorhombic crystal phase with nanocrystal sizes varies from 22 nm to 31 nm. The Scavenger test in presence of the scavenging elements BQ, IPA, ethanol and EDTA have been discussed. The stability test showed that SnSe NFs is a good and stable catalysis for practical applications. The effect of the NFs, NPs, NFLs on red blood cell showed that all the tested SnSe nanostructures had <2 % hemolysis, suggesting their hemocompatible nature.

Determination of the effect of low concentration titanium dioxide nano fuel additive in biodiesel on performance and emissions

In this study, the effect of nanoparticle addition into rapeseed methyl ester (R0) produced by the transesterification method on engine performance and emissions was experimentally investigated. Titanium dioxide was used as a nano fuel additive and was added to the test fuels at rates of 50 ppm (RTi50) and 75 ppm (RTi75) using an ultrasonic mixer. The effect of titanium dioxide on engine performance and exhaust emissions was experimentally determined by taking advantage of its photocatalysis effect and chemical reaction accelerator properties. Additionally, titanium dioxide additive reduced the viscosity and density of biodiesel fuel, resulting in higher micro explosion. According to the test results carried out at 4 different engine loads, brake specific fuel consumption decreased by 7.51% and 8.62% in RTi50 and RTi75 fuels compared to R0 fuel. Brake thermal efficiency increased by 2.47% and 6.21%, respectively. The improvement in combustion achieved by the nano additive increased the conversion of CO emissions into CO2, increased NOX emissions, reduced smoke emissions and caused more complete combustion products to come out of the exhaust.

Bionic solar-Driven interfacial evaporator for synergistic photothermal-Photocatalytic activities and salt collection during desalination

Solar-driven interfacial evaporation plays an essential part in the production of potable water. Nevertheless, the intricate water conditions in real-world scenarios continue to pose limitations on its utilization. This study prepared a novel bionic PPy/BiVO4-PI/MXene aerogel composite material with radial center structure through directional freezing as the evaporator, which integrates both photothermal and photocatalytic properties into the evaporation system. In order to evaluate the efficacy of photocatalytic degradation and salt collection during interfacial evaporation, high-concentration saline water, simulated seawater and dyeing wastewater were employed as substitutes for real contaminated water bodies. After being exposed to 1 kW/m−2(−|-) of irradiation, the PPy/BiVO4-PI/MXene composite exhibits an evaporation rate of 1.64 kg m-2h−1 and achieves a photothermal efficiency of 96.77 %. In high-concentration saltwater containing 20 wt% NaCl, the PPy/BiVO4-PI/MXene exhibited an evaporation rate of 1.32 kg m-2h−1 and a photothermal conversion efficiency of 77.41 %. Furthermore, approximately 26.7 g of salt can be collected after 15 days’ continuous evaporation. Furthermore, the PPy/BiVO4-PI/MXene demonstrated exceptional photocatalytic capabilities to organic dyes such as MB, RhB, CR and MG with removal efficiencies of 79.28 %, 70.96 %, 76.70 % and 80.95 %, respectively. This study realizes the synergistic effect of interfacial evaporation, photocatalysis and salt collection, providing a highly promising choice for the treatment of high-salt dyeing wastewaters.

Intrinsic metal ion dual-regulated fabrication of multifunctional nano-interfacial BiFeVO4/Fe-MOF for high photo-Fenton-like synergistic catalytic oxytetracycline removal

Great disparity in crystal size and incompatibility in crystal interface of catalysts lead to low catalytic activity, restricting its application for antibiotic degradation. Herein, a dual regulation strategy via intrinsic ion interpenetration was proposed to engineer multifunctional nano-interfacial BiFeVO4/NH2-MIL-88B(Fe-Bi) (BFV/NMFB) catalysts for efficient photo-Fenton-like catalytic degradation OTC. These multifunctional nano-interfaces (Fe-O-Bi) with abundant vacancy defects enhanced electrical conductivity, broadened light absorption and narrowed band gap. Furthermore, the strong interface bonds enhanced H2O2 adsorption and activation, accelerated photogenerated carrier separation/transfer and promoted Fe3+/Fe2+ redox activity. These properties gave an excellent synergistic effect of photo and Fenton-like catalysis (synergy factor up to 4.6) via changing photocurrent transfer pathway and interfacial adsorption-activation mechanism. Therefore, the designed BFV/NMFB exhibited superior photo-Fenton-like catalytic activity (ka = 189 mol‧mg−1‧min−1), about 3.6–58 times higher than these of reported catalysts. The proposed strategy provided a promising method for the design of MOFs composition for application of antibiotic degradation.

Facile fabrication of multifunctional superhydrophilic composite membranes for efficient oil-in-water emulsion separation

Numerous superwetting separation membranes have been designed for the management of oily wastewater due to their highly efficient oil/water separation efficiency. However, the long-term stability of these developed membranes is still restricted by membrane fouling. In this study, we synthesized multifunctional superhydrophilic membranes with superior anti-adhesive and anti-biofouling properties through simple co-deposition of dopamine, polyethyleneimine and CoFe2O4 (CFO) photocatalyst on the porous PVDF substrates for sustainable management of oil-in-water emulsion. The resultant optimal composite membranes showed the superhydropilicity with an underwater oil contact angle of 162.4° and achieved ca. 99.51 % oil/water separation efficiency with a maximum permeability of 232.2 L·m−2·h−1 in the treatment of oil-in-water emulsions driven by gravity. Moreover, the outstanding antibacterial performance of composite membrane was demonstrated by a nearly 100 % antibacterial rate during the exposure in 120-min visible light irradiation. Based on the synergistic effect of superhydrophilicity and photocatalysis, the fabricated composite membranes experienced a stable gravity-driven oil/water separation (oil rejection: >99.46 %) even after a 50-cycle filtration. Such an impressive filtration performance of the polydopamine/PEI/CFO composite membranes highlights their promising potential for sustainable and efficient treatment of oily wastewater.

Pyroelectric field drived photocatalysis by ZnFe2O4/NaNbO3 heterojunction for dye degradation through integration of solar and thermal energy

A novel composite of ZnFe2O4/NaNbO3 (ZFO/NNO) nanorods with a p-n heterojunction structure was successfully synthesized via the hydrothermal method. The NNO nanorods were heated in situ using the photothermal effect of ZFO and subsequently cooled to room temperature, creating a cyclic heating and cooling process for ZFO/NNO. The catalytic activity of the resulting nanorods was assessed through the degradation of Rhodamine B, reaching 98% degradation efficiency after 180 min, attributed to the synergistic effect of pyrocatalysis and photocatalysis. Compared with NNO and ZFO individually, the enhanced performance of ZFO/NNO can be attributed to several synergistic factors, including the expanded spectral range of light absorption for ZFO, the establishment of the built-in electric field of the p-n junction between ZFO and NNO, and the NNO pyroelectric effect that further improved the charge transfer efficiency. Superoxide radicals and holes generated from photo-induced electrons were identified as the active species. Hydroxyl radicals generated from pyroelectrically-induced charge also participated in catalytic reaction. The combined effect of pyroelectric and photocatalytic processes could significantly improve the coupled pyro-photocatalytic reaction for pyroelectric semiconductor heterostructure, enabling the utilization of multiple energy sources, including solar and thermal energy.

Engineering Thermally Reduced Graphene Oxide for Synchronously Enhancing Photocatalytic Activity and Photothermal Effect.

The structural composition of reduced graphene oxide (rGO) can be modified and controlled by appropriate reduction methods to modulate its electronic structure, rendering it a versatile platform for tailoring optoelectronic and catalytic properties. Nevertheless, it is uncommon to concurrently amplify the photocatalytic and photothermal effects when regulating and utilizing pure rGO. Here, we investigate the impact of structural variations in thermally reduced graphene oxide (TGO) on its photocatalytic and photothermal properties. Various characterization results demonstrate that appropriate thermal reduction facilitates the preservation and transformation of oxygenated groups and structure defects, which in turn encourages the formation of reactive carbon radicals and discrete graphitic domains, thereby strengthening the activation of molecular oxygen and the plasmonic photothermal effect under near-infrared (NIR) light irradiation. Moreover, the optimized TGOs exhibit efficient sterilization with NIR irradiation due to enhanced photocatalytic activities and photothermal effects. This work highlights the potential for developing photocatalytic and photothermal rGO-based materials through structural engineering.

Enhanced photocatalytic performance of (Mg, Cu) Dual-Doped ZnS nanosheets for Solar-Driven water treatment and embedded with PVA polymer membrane for reusability

Photocatalysis uses semiconductor materials to solar energy effectively purify to water by eliminating pollutants. Organic Dye degradation serves as a standard to assess the photocatalytic effects of the materials. In this study Mg, Cu dual-doped ZnS nanosheets were synthesized using the coprecipitation method. The impact of the concentration on the structural, morphology, optical, and degradation efficiency was investigated with XRD, XPS, TEM with EDAX, and UV spectroscopy. The pure ZnS and Zn0.98-xCu0.02MgxS (x = 0, 0.01, 0.02) (ZCM1, ZCM2, ZCM3, and ZCM4) nanosheets, exhibited cubic structure with high phase purity. The average crystalline size was calculated as 1.66, 1.60, 1.45, and 1.47 nm for the ZCM1, ZCM2, ZCM3, and ZCM4 nanosheets, respectively. TEM analysis revealed the presence of crumpled nanosheets. The bandgap of the ZCM1, ZCM2, ZCM3, and ZCM4 nanosheets were 3.99, 3.78, 4.03, and 4.09 eV respectively. This study investigated the photocatalytic activity of crystal violet dye when exposed to natural sunlight irradiation. Notably, ZCM3 nanosheets exhibited a high degradation rate of 99 % over 120 min under sunlight. Furthermore, the proposed dye degradation mechanism, effect of dosage, effect of dye variation, reusability, scavenging activity, and hemolytic activity were comprehensively discussed. The nanosheets embedded with the Polyvinyl alcohol (PVA) polymer membrane for reusability.

1 T/2 H mixed phase MoS2 nanosheets decorated with Ag nanoparticles for effective photocatalysis of organic dyes for wastewater treatment

The rapid industrialization and urbanization have led to the proliferation of organic dyes in wastewater, necessitating the development of efficient and sustainable treatment technologies. We report here a novel photocatalyst based on 1 T/2 H mixed-phase molybdenum disulfide nanosheets (1 T/2 H-MoS2 NSs) decorated with silver (Ag) nanoparticles for the enhanced photodegradation of both cataionic and anionic organic dyes under natural sunlight. Hydrothermally synthesized silver nanoparticles decorated 1 T/2 H MoS2 nanosheets (Ag-1 T/2 H MoS2 NSs) are characterized through X-ray diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM), Transmission Electron Microscopy (TEM), Raman spectroscopy, UV–vis spectroscopy, and Photoluminescence (PL) spectroscopy. FESEM results reveal that MoS2 NSs of thickness 17 nm clustered into nanoflowers where Ag nanoparticles are embedded in them. XRD results show the characteristic diffraction peaks at 2ϴ value 9.80 and 32.380 for (002) and (100) planes respectively. Photocatalytic performance has been evaluated by the degradation of Crystal Violet (CV) and Methyl Orange (MO) under direct sunlight irradiation. Nanocomposites exhibit a significant improvement in degradation efficiency i.e. 97 % for both (CV) and (MO) in 15 minutes and 25 minutes respectively compared to pure MoS2. The superior activity of the Ag-1 T/2 H MoS2 composite is attributed to the synergistic effects of the mixed-phase MoS2 structure and the charge transfer phenomenon provided by Ag nanoparticles. This work highlights the potential of Ag-1 T/2 H MoS2 NSs as an effective photocatalyst for the treatment of dye-contaminated wastewater.

Synthesis of carbon dots with tailored heteroatomic structure for achieving ultrahigh effectiveness in persulfate activation

Carbon dots (CDs) are normally feature with zero-dimensional structure, excellent solubility, good biosafety, and exceptional photoelectronic properties, thus, awakening the homogeneous-like photocatalytic potency of CDs in peroxymonosulfate (PMS) activation can afford new idea for water body remediation. Herein, we presented a facile nitrogen and sulfur co-doping strategy for the development of high-performance CDs-based photocatalysts. Through the deep investigation on the structure-activity relationship, we proposed that the incorporated pyridinic N within CDs structure could serve as efficient Lewis basic sites for PMS confinement. Importantly, the co-existence of oxidized sulfur groups and specific nitrogen speciation (pyridine N and pyrrolic N) induced unique “push-pull” effect on the photogenerated carriers within the surface state of S,N co-doped CDs. The unique synergy sites and surface hydrophilic nature conferred the CDs exceptional photocatalytic effectiveness, presenting a remarkable PMS consumption ratio of 7.62 per gram of the CDs photocatalyst within just 20 min. Profited from the improved kinetics of interfacial reactions, the CDs-photocatalyzed oxidation system that consisted largely of sulfate radicals can completely degrade rhodamine B within 12.5 min, and hold great potential in long-term operation without needing to regenerate CDs catalyst.

Microfluidic Platform for Semiconductor and MOF Integrated Photocatalysts: A Review over Synthesis Approaches and Applications

AbstractThe synergy of integrating semiconductors and MOF photocatalysts is the chief motive for this review paper. This merit has been combined with the microfluidic platforms, which are the cutting‐edge technology of synthesis. The microfluidic synthesis of semiconductors and MOF photocatalysts are categorized according to morphology and linker, respectively. Enhancing the effectiveness of photocatalysis comes along with adding a proper amount of electron acceptor or hole scavenger, combing electrochemical with photocatalytic degradation, and optimizing the photocatalyst band gap. Moreover, approaches for improving photocatalytic activity of MOFs can be classified as functionalization of organic linkers/metal centers, sensitization, incorporation of nanoparticles, and hybridization with semiconductors. Finally, the current applications of microfluidic devices, from the detection of water quality parameters to the elimination of water contaminants, have been addressed.

Riboflavin as a Coloring Agent of Tablets Affects the Photostability of Manidipine after the Change of Dosage Forms

Manidipine (MP) is widely used for reducing high blood pressure. Calslot® (CALS) tablets, which are the original MP medicines, and their generic medicines have been used for patients in clinical situations. The authors hypothesized that the photodegradability of MP drug substance in CALS tablets might be enhanced when the tablets were photo-exposed after the change of the dosage form by the presence of riboflavin (RF), which is utilized as a coloring agent and a well-known photosensitizer. The present study clarified that RF enhanced the photodegradation of MP when the powders and the suspensions of CALS tablets were ultraviolet light (UV) irradiated. The addition of RF to the suspension of MP standard substances also promoted MP photodegradation along with the increase of the generation rate of its main photoproduct, benzophenone. Finally, the authors performed the photostabilization of MP suspensions based on the addition of quercetin (QU), which is one of polyphenols and has both the antioxidative potency and the UV filtering potency. It is summarized that QU has a protective potency for MP’s own photodegradation, and it partially suppresses the photocatalytic effect of RF. Further studies focused on the photochemical behaviors of utilized additives for medicines are needed for their safe use.

Inkjet‐Printed Flexible and Transparent Ti3C2Tx/TiO2 Composite Films: A Strategy for Photoelectrically Controllable Photocatalytic Degradation

The 2D Ti3C2Tx MXene has a large specific surface area, abundant functional groups, and low work function, which has potential in the field of photocatalytic materials. However, the manufacturing of controllable films with high photocatalytic properties and desirable transmittance is a challenging task. Herein, low‐cost, large‐scale, and rapid preparation of Ti3C2Tx/TiO2 flexible composite films have been successfully prepared by inkjet printing technology, which can be applied in complex and special environments, as well as in photoelectrically controllable places for photocatalytic performance. With the increase of the anatase TiO2, the transmittance of Ti3C2Tx/TiO2 films increases from 55.37% to 73.27% at 780 nm, corresponding to the square resistance of 1.112–206.496 kΩ sq−1 and the figure of merit of 0.48–0.005. When the amount of anatase TiO2 is 15%, the film has the best photocatalytic effect on methylene blue (MB) dye, reaching 68.94%. After five cycles of testing, the degradation efficiency of MB dye decreases by only 5.68%, showing that the film has good cycling stability. This work provides a new research direction for photoelectrically controllable photocatalytic degradation in complex and special environments.

LLDPE/TiO2 composites with high UV aging resistance and mechanical properties by controlling the alumina coating on TiO2

AbstractFor preparing high performance LLDPE film, the photocatalytic activity and the UV absorption capacity of TiO2 were regulated by the alumina coating content on the surface of TiO2. Alumina‐coated TiO2 was prepared by the chemical liquid deposition method, and characterized by element analysis, TGA, FTIR, and morphology observation. The alumina coating layer had been proven to covalently bind to the surface of TiO2 through AlOTi bonds, which formed a continuous and dense coating layer, followed by forming a loose flocculent coating layer with the increase of alumina content. The alumina coating layer could significantly reduce the formation of carbonyl group on the LLDPE chains, and enhance UV aging resistance of LLDPE by inhibiting the photocatalytic activity of TiO2. Moreover, the dispersion of alumina‐coated TiO2 in the LLDPE matrix was improved. Thus, the transmittance of LLDPE/alumina‐coated TiO2 composites was reduced and the whiteness was improved. Importantly, the continuous and dense alumina coating layer was enough to inhibit the photocatalysis effect of TiO2 on LLDPE. The further increase of alumina coating content reduced the UV absorption capacity of alumina‐coated TiO2 and its compatibility with the LLDPE matrix. Therefore, the best alumina coating content on the surface of TiO2 was 1.46 wt% for preparing high performance LLDPE/TiO2 composites.Highlights Alumina‐coated TiO2 with controllable coating thickness was successfully synthesized. LLDPE/alumina‐coated TiO2 has excellent UV aging resistance and mechanical properties. The photocatalytic activity and UV absorption capacity of TiO2 could be regulated. 1.46 wt% of alumina coating is the best content for high performance LLDPE/TiO2 composites.

Nickel-catalyzed in situ synthesis of UHMWPE/TiO2 composites with enhanced mechanical properties and adjustable photocatalytic degradabilities

Expanding the application field of polyolefin materials through functionalization has been a research hotspot in the past three decades. Here, a TiO2-supported anilinenaphthoquinone nickel catalyst was assembled and applied for in situ ethylene polymerization with high activity (>2000 kg mol–1h−1) to produce ultra-high molecular weight polyethylene (UHMWPE)/TiO2 composites with unique physicochemical performance. The UHMWPE/TiO2 composite films and fibers prepared by in-situ ethylene polymerization are superior to the samples from the blend system in issues such as TiO2 dispersibility, mechanical property, and photocatalytic degradability. The mechanical properties (strength up to 26.8 cN/dtex, modulus up to 1248.8 cN/dtex) of the obtained UHMWPE/TiO2 composite fibers are significantly improved with a very low dosage of TiO2 (as low as 1.4 wt‰). Moreover, UHMWPE/TiO2 composites obtained by coating Al2O3 and SiO2 on the surface of TiO2 not only retain the strong absorption of ultraviolet rays, but also effectively weaken the photocatalytic degradation effect.