Degradation Mechanism Research Articles

Engineering biomimetic scaffolds for bone regeneration: Chitosan/alginate/polyvinyl alcohol-based double-network hydrogels with carbon nanomaterials

In this study, new types of hybrid double-network (DN) hydrogels composed of polyvinyl alcohol (PVA), chitosan (CH), and sodium alginate (SA) are introduced, with the hypothesis that this combination and incorporating multi-walled carbon nanotubes (MWCNTs) and graphene nanoplatelets (GNPs) will enhance osteogenetic differentiation and the structural and mechanical properties of scaffolds for bone tissue engineering applications. Initially, the impact of varying mass ratios of the PVA/CH/SA mixture on mechanical properties, swelling ratio, and degradability was examined. Based on this investigation, a mass ratio of 4:6:6 was determined to be optimal. At this ratio, the hydrogel demonstrated a Young's modulus of 47.5 ± 5 kPa, a swelling ratio of 680 ± 6 % after 3 h, and a degradation rate of 46.5 ± 5 % after 40 days. In the next phase, following the determination of the optimal mass ratio, CNTs and GNPs were incorporated into the 4:6:6 composite resulting in a significant enhancement in the electrical conductivity and stiffness of the scaffolds. The introduction of CNTs led to a notable increase of 36 % in the viability of MG63 osteoblast cells. Additionally, the inhibition zone test revealed that GNPs and CNTs increased the diameter of the inhibition zone by 49.6 % and 52.6 %, respectively.

Design, preparation and mechanical properties of novel glass fiber reinforced polypropylene bending bars

Fiber reinforced thermoplastic composite bars offered the advantages of repeated molding, high toughness, and recyclability, making them a promising alternative to steel bars. For the stirrups applications in concrete structures, it was essential to develop efficient bending technologies for producing high-quality thermoplastic bending bars. In the present paper, the bending properties of glass fiber reinforced polypropylene (GFRPP) composite bars were investigated by experimental and theoretical methods. A novel bending fixture of GFRPP bars was specifically designed for GFRPP bars to ensure the reliable bending of the bars. Finite element simulation was employed to analyze the stress distribution of GFRPP bars, providing valuable insights into their mechanical behavior. Additionally, a bending strength model was developed based on the material mechanics, offering a theoretical framework for understanding and predicting the bending strength of GFRPP bars. Finally, the bending mechanism of bars was further revealed according to experimental and theoretical findings. The results of the study demonstrated that the specially designed bending fixture was successful in minimizing damage to the bending section of the GFRPP bars, leading to a significant improvement in bending strength retention of up to 43.2 %. Furthermore, the theoretical results and experimental test have a good agreement in terms of stress distribution and failure mode. The maximum strain in the transition zone between the straight section and the bending section of the GFRPP bars was nearly double that of the straight section at the same stress levels. With the increase of bending radius to diameter ratio from 3.0 to 7.0, the tensile strength of GFRPP bending bars increased by ∼7.9 %. The study identified the transition area between the bending section and straight section of GFRPP bars as the most critical failure point. The strength degradation mechanism during the bending were attributed to the shrinkage and torsion of inner fibers owing to the compression caused the local stress concentration, which caused the inner resin matrix to crack and interface debonding of fiber/resin, leading to the premature tensile failure.

UV-metal ion synergistic activation of ferrate(VI) for the degradation of dimethoate

The improvement in the degradation efficiency of dimethoate was achieved through the activation of UV light and metal ions. The study found that Fe(VI) was effectively activated by Cu(II), Fe(III), and Fe(II), resulting in an improved removal rate of dimethoate in water, with the activation efficiency of Cu(II) > Fe(III) > Fe(II). Under UV irradiation, the synergistic activation effects of UV-Cu(II) and UV-Fe(III) were most pronounced and positively correlated with light intensity. The mineralization rate of dimethoate by UV-Fe(III)-Fe(VI) reached up to 37%, significantly outperforming the Cu(II)-Fe(VI) system. The main active species in the Cu(II)-Fe(VI) and Fe(III)-Fe(VI) systems were Cu(III) and Fe(IV)/Fe(V), while those in the UV-Fe(III)-Fe(VI) were ·OH and ·O2- radicals, respectively. In the UV-metal ions activated Fe (VI) system, the main degradation mechanisms of dimethoate were hydrolysis, cleavage, oxidation, and recombination. The impacts of water quality parameters on degradation efficiency were also investigated, finding that Cl- had almost no effect, while SO42- had a slight repression effect, and HCO3-, CO32- and NO2- exhibited strong inhibitory effects. Finally, the promising application of the UV-metal ion-Fe(VI) system in actual water environments was proposed, achieving effective removal with minimal environmental risks.

Light-triggered defect dynamics in silicon wafers: understanding degradation mechanisms

Light-triggered defect dynamics in silicon wafers: understanding degradation mechanisms

Ti-MOG derived TiO2 facet heterojunction rich in C/Ti3+/Ov for adsorption-photocatalytic removal of pharmaceutical pollutants from water

Developing efficient, stable, and broad-spectrum responsive photocatalysts is an effective way to degrade pharmaceutical pollutants in water. In this work, using concentrated hydrochloric acid (HCl) as a modulator, titanium metal–organic gel (Ti-MOG) was prepared and used as a template for calcination in air to obtain anatase TiO2 facet heterojunction rich in C/Ti3+/oxygen vacancy (Ov) (MOG-TiO2), which has a hierarchical porous structure, large specific surface area, and highly dispersed active site. Compared to P25, P25 + C and MIL-125(Ti) derived TiO2 (MOF-TiO2), MOG-TiO2 exhibited obviously enhanced adsorption-photocatalytic performance for tetracycline (TC) and low concentrations ethenzamide (ETH) under broad-spectrum light irradiation. The photocatalytic degradation efficiency of ETH by MOG-TiO2 reached 92.8, 100 and 98.7 % within 240, 60 and 6 min under Vis, UV and VUV light illumination, respectively, which were much higher than those of P25 (62.7, 33.2 and 73.0 %), P25 + C (61.7, 31.2 and 72.5 %) and MOF-TiO2 (79.2, 86.8 and 88.7 %). Furthermore, concentrated HCl promoted the formation of Ti3+/Ov in MOG-TiO2, which was conducive to the improvement of its photocatalytic performance. MOG-TiO2 also displayed great adsorption-photocatalytic stability and reusability. Moreover, the biotoxicity of TC toward E. coli DH5a obviously decreased after photocatalytic degradation. Based on the TiO2 facet heterojunction rich in C/Ti3+/Ov and the generation of hole, hydroxyl radicals, and superoxide radicals, the possible photocatalytic degradation mechanism of MOG-TiO2 was proposed. Overall, this work provides insights into constructing a novel hierarchical porous carbon-doped facet heterojunction photocatalyst for efficient pharmaceutical contaminants removal.

Role of Mixed Oxidant and Controlled Oxygen Partial Pressure Heat Treatment to Regulate the Dielectric Properties and Resistivity of SrTiO3-based CP Ceramics

Sr0.99La0.01TiO3 (SLT10) colossal permittivity (CP) ceramic materials were synthesized using solid phase method and secondary heat treated using mixed oxidant 35%Bi2O3-10%Al2O3-20%MgO-25%CuO-10%SiO2 oxidant. The heat treatment atmospheres were chosen as O2, air, and Ar to correspond to different oxygen partial pressures. The dielectric properties of the Sr0.99La0.01TiO3-Percolated (SLT10-P) ceramics were investigated, and the contribution of the oxidant to the resistivity enhancement was verified by complex impedance spectroscopy and DC resistivity tests. Excellent dielectric properties were obtained for SLT10-P Air ceramic sample (16543 for dielectric permittivity and 0.016 for loss tangent), and the resistivity was increased from 2.13×108 Ω·cm (SLT10) to 1.23×1011 Ω·cm (SLT10-P Air). The resistance degradation mechanism of SLT10-P ceramics and oxygen vacancy migration in the process of resistance degradation were studied by using resistance monitoring device and thermally stimulated depolarization currents (TSDC) test. The introduction of oxidant optimizes the temperature stability and resistivity of SLT10 ceramics, but it will lead to the decrease of dielectric permittivity. The atmosphere of heat treatment changed the concentration of oxygen vacancy in ceramics. When SLT10-P O2 was treated in O2 atmosphere, the concentration of oxygen vacancy in ceramics decreased, which led to the decrease of dielectric permittivity and the increase of grain boundary resistance. For SLT10-P Ar ceramic, more oxygen vacancies and free electrons are induced by low oxygen partial pressure heat treatment, which enhances the dipole effect of electron pinning defects and leads to colossal dielectric permittivity, but high concentration of oxygen vacancies will affect the resistance decline. In SLT10-P Air ceramic, the coexistence of colossal permittivity and low loss tangent and high resistance is realized.

Electrochemical Analysis of an Electrolyte-Supported Solid Oxide Cell-Based MK35x Stack during Long-Term Electrolysis Operation

The currently ongoing scale-up of high-temperature solid oxide electrolysis (SOEL) requires an understanding of the underlying dominant degradation mechanisms to enable continuous progress in increasing stack durability. In the present study, the degradation behavior of SOEL stacks of the type “MK35x” with chromium-iron-yttrium (CFY) interconnects and electrolyte-supported cells (ESC) developed at Fraunhofer IKTS was investigated. For this purpose, the initial electrochemical performance of a 10-cell stack was characterized in various operating conditions in both fuel cell and electrolysis mode. Degradation was evaluated during galvanostatic steady-state steam electrolysis operation for more than 3000 h at an oxygen side outlet temperature of 816 °C and a current density of −0.6 A cm−2 and showed an average voltage evolution rate of −0.3%/kh demonstrating high stability. Initial and final characterization at the part load operating point at −0.39 A cm−2 and 800 °C led to the determination of a positive overall degradation rate of 0.4%/kh showing a considerable impact of the operating conditions on the degradation rate. By means of electrochemical impedance spectroscopy analysis it was shown that the stack’s ohmic resistance increased whereas the polarization resistance decreased most likely due to an enhancement in LSMM’/ScSZ oxygen electrode performance.

Catalyst residues severely impact the thermal stability and degradation mechanism of polycarbonates: How to turn a flaw into an opportunity

Three poly(cyclohexene carbonates) with molecular weights ranging from 4.9 to 9.4 kg/mol were synthesized from cyclohexene oxide and CO2 using macrocyclic phenolate dimetallic catalysts and purified by conventional purification procedure. A decrease in thermal stability of approximately 100 °C was observed in comparison to poly(cyclohexene carbonates) with similar molecular weights synthesized using salen metal catalysts. This decrease derives from the presence of traces of dimetallic catalyst which is able to promote the depolymerisation of poly(cyclohexene carbonate) to CO2 and cyclohexene oxide in contrast to the usual backbiting mechanism that leads to cyclic carbonate. The onset of the degradation can be precisely tuned by changing the amount of residual dimetallic catalyst or including species with functional groups that can reduce the availability of the catalytic centers. Therefore, the possibility of controlling the thermal stability of poly(cyclohexene carbonates) by varying the concentration of the catalyst and the surrounding chemical environment paves the way for the use of these polymers as components in self-sacrificial materials of interest for advanced applications.

Degradation of diethyl phthalate by photolysis of hydrogen peroxide electrogenerated using a Printex L6 carbon modified with Benzophenone cathode in an improved tangential flow cell

In this work, a gas diffusion electrode (GDE) made of Printex L6 carbon modified with 2.0% w/w of benzophenone-3,3′,4,4′-tetracarboxylic dianhydride (PL6C/BTDA 2%) was employed as cathode in a new 3D printed electrochemical cell with tangential flow. With this configuration, the performance of the technology was evaluated for hydrogen peroxide (H2O2) electrogeneration and remediation of aqueous wastes contaminated with diethyl phthalate (DEP) using different H2O2-based advanced oxidation processes (AOPs). The electrogeneration study was carried out varying the current density applied to the system, and it was found that 50mAcm-2 was the best performing value, resulting in remarkable faradaic efficiencies of nearly 100%. This led to the production of higher amounts of H2O2 (442.5mgL-1) in 90minutes at an acceptable energy consumption (8.5 kWh kg-1) compared to values reported in the literature. Based on these findings, H2O2-based AOPs were employed to investigate the removal of DEP in cathodic compartment, including mediated electrochemical degradation with electrogenerated H2O2 (e-H2O2) and the integration of this technology with ultraviolet-C (UVC) photolysis (e-H2O2/UVC). The integrated e-H2O2/UVC obtained the best performance compared to single photolysis and e-H2O2, leading to the total elimination of DEP (90 μmol L-1) within only 30min of treatment, reaching the highest kinetic rate constant (0.3min-1). Fifteen by-products, generated through oxidation processes studied, were successfully identified by LC-MS/MS, enabling the proposal of the degradation mechanism of DEP.

Selective oxidation behavior based on iron-doped MOF derived carbon-based catalysts: Active site regulation and degradation mechanism analysis

Selective removal of target organic pollutants in complex water quality of municipal sewage is extremely important for the deep treatment of water quality. Here, energetic MOF and Fe-MOF are doped in electrostatic spinning process to adjust the structure and composition of the catalysts, active oxygen species (ROSs), realizing the selective removal of organic pollutants. Non-azo and azo pollutants are selected as target pollutants. Catalysts PCFe-8 with Fe nanoclusters, EPCFe-8 with Fe-Nx, and EPC-8 without Fe doping are used to activate peroxymonosulfate (PMS) for degrading pollutants. The results show that the PCFe-8/PMS system can produce the most SO4− and exhibit superior removal of azo pollutants, whereas the degradation behavior of non-azo pollutants is more inclined to occur in the EPCFe-8/PMS system and the EPC-8/PMS system. This work provides a reference for elucidating the relationship between catalyst structure and components, types of ROSs, and selective degradation of pollutants.

Efficient photodegradation of antibiotics by g-C3N4 and 3D flower-like Bi2WO6 perovskite structure: Insights into the preparation, evaluation, and potential mechanism

Antibiotics are emerging organic pollutants that have attracted huge attention owing to their abundant use and associated ecological threats. The aim of this study is to develop and use photocatalysts to degrade antibiotics, including tetracycline (TC), ciprofloxacin (CIP), and amoxicillin (AMOX). Therefore, a novel Z-scheme heterojunction composite of g-C3N4 (gCN) and 3D flower-like Bi2WO6 (BW) perovskite structure was designed and developed, namely Bi2WO6/g-C3N4 (BW/gCN), which can degrade low-concentration of antibiotics in aquatic environments under visible light. According to the Density Functional Theory (DFT) calculation and the characterization results of X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FITR), Scanning electron microscopy - energy spectroscopy (SEM-EDS) and X-ray photoelectron spectroscopy (XPS), this heterojunction was formed in the recombination process. Furthermore, the results of 15 wt%-BW/gCN photocatalytic experiments showed that the photodegradation rates (Rp) of TC, CIP, and AMOX were 92.4%, 90.1% and 82.3%, respectively, with good stability in three-cycle photocatalytic experiments. Finally, the quenching experiment of free radicals showed that the holes (h+) and superoxide radicals (·O2−) play a more important role than the hydroxyl radicals (·OH) in photocatalysis. In addition, a possible antibiotic degradation pathway was hypothesized on the basis of High performance liquid chromatography (HPLC) analysis. In general, we have developed an effective catalyst for photocatalytic degradation of antibiotic pollutants and analyzed its photocatalytic degradation mechanism, which provides new ideas for follow-up research and expands its application in the field of antibiotic composite pollution prevention and control.

A novel g-C3N4@La:Y2O3 nanocomposite fluorescence sensor for simultaneous determination and photocatalytic degradation of Ulipristal acetate and Tacrolimus using Doehlert design optimization

Graphitic carbon nitride nanocomposite doped with La:Y2O3 was used as a new sensor for detection and determination of two hazardous active pharmaceutical compounds, Tacrolimus and Ulipristal acetate, by fluorescence spectrophotometry. This novel nanosensor has a fantastic ability to detect these drugs quickly, accurately, and simultaneously. The effect of Tacrolimus on this nanosensor is the quenching of fluorescence emission intensity at the wavelength of 369 nm while the Ulipristal acetate increases the fluorescence emission at 433 nm. Doehlert design was used to optimize the effective factors to reach the maximum fluorescence emission intensity of the nanosensor. Factors including pH, buffer solution concentration and the ratio of La:Y2O3 dopant in the nanocomposite structure. Under optimal conditions, the limit of detection of 17 nM and the limit of qualification of 58 nM for Tacrolimus and the limit of detection of 11 nM and the limit of qualification of 36 nM for Uipristal acetate were obtained with good accuracy. The prepared g-C3N4@La: Y2O3 nanocomposite has a reasonable ability to photodegrade these two drugs. In this regard, the process of photocatalytic degradation of Tacrolimus and Ulipristal acetate was investigated under visible light irradiation. The effect of active species in photocatalytic degradation was evaluated in order to determine the exact degradation mechanism, and the effect of Fenton factors on analytes degradation was also investigated.

Nb speciation and microstructural characterization of the oxide layer formed on neutron-irradiated Zr-2.5 Nb alloy in high-temperature water

It is crucial to understand the degradation mechanisms of the alloy Zr-2.5Nb, which make the pressure boundary in Canada Deuterium Uranium reactors. In the present study, Zr-2.5Nb coupons were exposed for 567 days at 325 °C with and without neutron-irradiation in simulated primary water chemistry. A combination of scanning/transmission electron microscopy with energy dispersive X-ray spectroscopy, and electron energy loss spectroscopy was used to investigate the base metal and oxide. The obtained results suggest that the distribution of nanopores and the variation in Nb oxidation state likely create a gradient in the oxygen concentration and electrochemical potential through the film.

Data-driven diagnosis of high temperature PEM fuel cells based on the electrochemical impedance spectroscopy: Robustness improvement and evaluation

Utilizing machine learning techniques for data-driven diagnosis of high temperature PEM fuel cells is beneficial and meaningful to the system durability. Nevertheless, ensuring the robustness of diagnosis remains a critical and challenging task in real application. To enhance the robustness of diagnosis and achieve a more thorough evaluation of diagnostic performance, a robust diagnostic procedure based on electrochemical impedance spectroscopy (EIS) and a new method for evaluation of the diagnosis robustness was proposed and investigated in this work. To improve the diagnosis robustness: (1) the degradation mechanism of different faults in the high temperature PEM fuel cell was first analyzed via the distribution of relaxation time of EIS to determine the equivalent circuit model (ECM) with better interpretability, simplicity and accuracy; (2) the feature extraction was implemented on the identified parameters of the ECM and extra attention was paid to distinguishing between the long-term normal degradation and other faults; (3) a Siamese Network was adopted to get features with higher robustness in a new embedding. The diagnosis was conducted using 6 classic classification algorithms—support vector machine (SVM), K-nearest neighbor (KNN), logistic regression (LR), decision tree (DT), random forest (RF), and Naive Bayes employing a dataset comprising a total of 1935 collected EIS. To evaluate the robustness of trained models: (1) different levels of errors were added to the features for performance evaluation; (2) a robustness coefficient (Roubust_C) was defined for a quantified and explicit evaluation of the diagnosis robustness. The diagnostic models employing the proposed feature extraction method can not only achieve the higher performance of around 100% but also higher robustness for diagnosis models. Despite the initial performance being similar, the KNN demonstrated a superior robustness after feature selection and re-embedding by triplet-loss method, which suggests the necessity of robustness evaluation for the machine learning models and the effectiveness of the defined robustness coefficient. This work hopes to give new insights tothe robust diagnosis ofhigh temperature PEM fuel cells andmore comprehensive performance evaluation of the data-drivenmethod fordiagnosticapplication.

Discrete element modelling of the elastic-plastic and viscoelastic properties of a lithium-ion battery electrode layer

Mechanical degradation mechanisms are one of the leading causes of charge capacity loss in lithium-ion batteries. This study further develops a discrete element method (DEM) simulation framework, which investigates how the local contact behaviour affect the mechanical properties of the global active layer. The local microstructure consists of active particles held together by a binder domain, making up a granular medium. This study investigates the impact of the layer's global properties from the type of particle contact model. Experiments were also performed to measure size distribution and the material properties of the active material. The time dependency of the active layer, stemming from the viscoelastic binder domain, was studied in relaxation simulations, which were based on experimental measurements.

An Improved Hot Spot Mitigation Approach for Photovoltaic Modules Under Mismatch Conditions

The reduction of photogenerated current in photovoltaic (PV) cells due to various degradation mechanisms leads to hot spot (HS) generation, resulting in serious safety and reliability concerns. This article presents a novel hot spot mitigation circuit (HSMC), which effectively counters HS formation in cells under mismatch situations, improving the reliability of the entire PV arrangement. The effectiveness of the proposed HSMC is compared extensively with the conventional bypass diode (BPD) through experimentation on a 3×1 PV string and a 3×3 series-parallel (SP) PV array in an outdoor setting. Detailed thermographic analysis showed that the maximum temperature of the PV module under low shading levels reached 119.16% and 54.11% higher with the traditional BPD than with the proposed HSMC when tested on a 3×1 PV string and 3×3 SP PV array, respectively. This indicates that the mismatched cell was subjected to elevated temperatures with BPD. Moreover, the experimental results confirm that the proposed HSMC resulted in enhanced power output and a significant reduction of power loss in the bypass path of the shaded module under increased shading levels compared to the traditional BPD. The proposed HSMC reduced mismatch loss by up to 89.82% when tested on a 3×1 PV string.

Influence of glass-phase structure on the degradation of rare-earth (Y2O3, La2O3)-doped CaO–Al2O3–SiO2–B2O3 glass-ceramics in citric acid solution

Liquid-phase sintering anorthite (LSA) glass-ceramics with degradation in citric-acid solution have been prepared from CaO–Al2O3–SiO2–B2O3 low-melting compositions. By means of the chemical corrosion of the glass phases, LSA glass-ceramics are effectively degraded in the citric acid solution. Then, the influence of B2O3 and rare-earth (RE) on the structures of glass phases, the degradation of LSA glass-ceramics in the citric-acid solutions, and the dielectric properties are investigated systematically. The results suggest that when the B2O3 molar ratio in the composition CaO–Al2O3–SiO2–B2O3 is 0.5, doping LSA glass-ceramics with RE can reduce the quantity of bridging oxygen and [BO4] units in the glass phase, as well as the degree of network connection of [AlO4] units in the glass network. Conversely, when the B2O3 molar ratio is decreased down to 0.3, doping RE into LSA glass-ceramics increases the quantity of bridging oxygen and [BO4] units for glass phase. This improvement in chemical stability effectively impedes the degradation of LSA glass-ceramics in citric-acid solutions. Concurrently, the degradation mechanism of LSA glass-ceramics in citric acid solution is analyzed and explained in terms of classical glass corrosion theory, while the microstructural characteristics of LSA glass-ceramics are utilized to investigate their dielectric properties. It indicates that the dielectric loss and dielectric constant of LSA glass-ceramics are significantly lowered as a result of the existence of the glass phase. Especially when the B2O3 molar ratio in the composition CaO–Al2O3–SiO2–B2O3 is 0.3, and the La2O3 doping percentage into LSA glass-ceramics is 0.5 wt%, the LSA glass-ceramics exhibit the lowest dielectric loss value of 3.13 × 10−3 and εr = 4.17. Developing the LSA glass-ceramic with degradation in organic acids can provide a new idea for the recycling and disposal of e-waste.

Hydrothermal preparation of magnetic recyclable In-doped MoO3/SrFe12O19 ternary nanocomposites with enhanced visible-light-driven photocatalytic performance

SrFe12O19 as a novel magnetic matrix has drawn increasing attention in photocatalysis. In the current study, a novel magnetically recoverable In-MoO3/SrFe12O19 ternary composite photocatalyst was fabricated with the hydrothermal method, and the photocatalytic activity was evaluated by degrading rhodamine B (RhB) solution through simulated solar irradiation. The results demonstrated that the outstanding degradation rate of RhB (96.5%) could be achieved within 70 min when the mass ratio of both doped In and SrFe12O19 in the ternary composite photocatalyst was 5% (5-IMS-5). The enhancement of the photocatalytic degradation performance was mainly related to the self-sensitization of RhB, the magnetic field effect of SrFe12O19, and the introduction of impurity energy levels by In doping. More importantly, the degradation rate of RhB by 5-IMS-5 was still up to 90.8% after 4 times of recycling, verifying that the prepared ternary composite sample has good recyclability and stability. This study proves a novel ternary composite photocatalyst that can be used for organic wastewater treatment, and its photocatalytic degradation mechanism provides great reference significance for the synthesis of other SrFe12O19-based magnetic semiconductor photocatalysts.

TiO2@Ti3C2Tx@ZnFe2O4-based long-lasting filter with photocatalytic activity

In the present work, the novel TiO2@Ti3C2Tx@ZnFe2O4 composites were synthesized by an ultra-sonicated method. The influence of MXene content and ZnFe2O4 nanoparticles on the photocatalytic performance and degradation efficiency of methylene blue (MB) solution were studied by different measurements such as X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), Electrochemical impedance spectroscopy (EIS), and ultraviolet (UV)-visible spectroscopy. Among synthesized composites, the optimum photocatalyst showed excellent degradation efficiency of MB solution (100 % in 2 h) and high photocatalytic activity compared to the Ti3C2Tx and TiO2@Ti3C2Tx composites. The degradation mechanism of MB dye by TiO2@Ti3C2Tx@ZnFe2O4 composites was illuminated through kinetic studies. The results demonstrated the key role of ZnFe2O4 nanoparticles in dye removal. In addition, the optimum composite was deposited on nickel foam to construct a novel filter and photocatalytic measurements with long-time experiments had shown the stability and photocatalytic performance of the synthesized filter. Therefore, the optimal TiO2@Ti3C2Tx@ZnFe2O4 composite exhibits significant promise for practical water pollution degrading applications.

Construction of coordination polymer [Ni(ppda) (tib) (H2O)]·H2O and photocatalytic degradation of indigo carmine

Semiconductor coordination polymers have garnered significant attention as photocatalysts for wastewater treatment owing to their adaptable structure, expansive specific surface area, and outstanding selectivity, stability, and sensitivity. In this study, coordination polymer [Ni(ppda) (tib) (H2O)]·H2O was synthesized utilizing flexible phenyldiacetic acid (H2ppda) and rigid 1,3,5-tris(1-imidazolyl)benzene (tib). Crystal structure analysis revealed that the three-linked tib ligands and the central Ni(II) ion create a wavy 2D surface. Additionally, cis-ppda2- ligands form a 1D wave chain alongside central Ni(II), which traverse through a 2D layer. Adjacent layers are interlaced via ppda2−, resulting in a complex 3D supramolecular structure. The fundamental framework of [Ni(ppda) (tib) (H2O)]·H2O exhibits stability up to 316 °C and remains stable over 5 cycles, with a band gap energy of 2.9 eV, rendering it a viable candidate for catalytic applications. In aqueous systems, [Ni(ppda) (tib) (H2O)]·H2O demonstrates efficient photocatalytic degradation of Indigo Carmine (IC), achieving a degradation rate of 98.5% and a reaction rate of 0.027 min−1, showcasing commendable selectivity and semiconductor properties. The primary photocatalytic degradation mechanism involves the synergistic formation of ·OH and ·O2- active species through the interaction between [Ni(ppda) (tib) (H2O)]·H2O and H2O2, facilitating the oxidative degradation of dye molecules.