Fenton-like Catalytic Activity Research Articles

Highly Crystalline Copper Aluminum-Layered Double Hydroxides with Intrinsic Fenton-Like Catalytic Activity for Robust Oral Health Management.

As the main challenge of dental healthcare, oral infectious diseases are highly associated with the colonization of pathogenic microbes. However, current antibacterial treatments in the field of stomatology still lack a facile, safe, and universal approach. Herein, we report the controllable synthesis of copper aluminum-layered double hydroxides (CuAl-LDHs) with high Fenton-like catalytic activity, which can be utilized in the treatment of oral infectious diseases with negligible side effects. Our strategy can efficiently avoid the unwanted doping of other divalent metal ions in the synthesis of Cu-contained LDHs and result in the formation of binary CuAl-LDHs with high crystallinity and purity. Evidenced by experimental and theoretical results, CuAl-LDHs exhibit excellent catalytic ability toward the ·OH generation in the presence of H2O2 and hold strong affinity toward bacteria, endowing them with great catalytic sterilization against both Gram-positive and Gram-negative bacteria. As expected, these CuAl-LDHs provide outstanding treatments for mucosal infection and periodontitis by promoting wound healing and remodeling of the periodontal microenvironment. Moreover, toxicity investigation demonstrates the overall safety. Accordingly, the current study not only provides a convenient and economic strategy for treating oral infectious diseases but also extends the development of novel LDH-based Fenton or Fenton-like antibacterial reagents for further biomedical applications.

Multifunctional trimetal-organic frameworks with enhanced fenton-like catalytic activity for inhibiting bacteria

AbstractAntibiotics and chemical disinfectants usually have serious problems of drug resistance and biosafety. Metal-organic frameworks (MOFs), as a new alternative method, have been studied to inhibit bacteria attributed to their tunability of compositions and structures, ideal biocompatibility and great catalytic properties. In the current study, two trimetal-organic frameworks (Ni1Co1Fe1-MOFs and Ni6Co3Fe1-MOFs) with different atomic ratios of Ni/Co/Fe were synthesized by a simple one-pot room temperature method. The fabricated MOFs showed outstanding Fenton-like catalytic activities and Ni1Co1Fe1-MOFs exerted greater catalytic activity. Based on a Fenton-like reaction, a high-efficiency antibacterial system was constructed. The manufactured Ni1Co1Fe1-MOF/sodium alginate composite coating delayed the weight loss of apple chunks and effectively inhibited E. coli bacteria from polluted apple chunks after storage for 2 d, significantly improving the fruit storage. This study proposed a novel and effective antibacterial strategy, which would open up a promising idea for the exploitation of food antibacterial agents in the future.

Metal-free diatomaceous carbon-based catalyst for ultrafast and anti-interference Fenton-Like oxidation

Herein, a diatomite biomorphic Si-O doped carbon-based catalyst (DB-SiOC) was prepared using natural mineral diatomite as the silicon source and porous template. The results showed that the metal-free DB-SiOC catalyst exhibited ultrafast oxidation towards chlorophenol (CP) via peroxymonosulfate (PMS) activation, which was almost one order of magnitudes than most of carbon-based catalysts. The DB-SiOC/PMS system also showed the high ability to resist the interference of environmental matrix. The radicals (•OH and SO4•‒) exhibited a very small contribution to the CP oxidation while the electron transfer processes (ETP) played the major role in the DB-SiOC/PMS system. The electron shuttles from the electron-donating CP molecules to the adjacent DB-SiOC/PMS* could be efficiently triggered via Si-O bonds as bridges, making it possible for ultrafast oxidation of CP. In addition, the hollow-disc shaped DB-SiOC provided the biomorphic DE structures with abundant pores for enriching the PMS and pollutants, thus further accelerating the oxidation reaction. This work provided a new routine for the fabrication of Si-O doped carbon-based catalysts with excellent Fenton-like catalytic activity, which would greatly promote their application prospects in Fenton-like systems.

Cobalt-based hybrid nanoparticles loaded with curcumin for ligand-enhanced synergistic nanocatalytic therapy/chemotherapy combined with calcium overload.

The therapeutic efficacy of Fenton or Fenton-like nanocatalysts is usually restricted by the inappropriate pH value and limited concentration of hydrogen peroxide (H2O2) at the tumor site. Herein, calcium carbonate (CaCO3)-mineralized cobalt silicate hydroxide hollow nanocatalysts (CSO@CaCO3, CC) were synthesized and loaded with curcumin (CCC). This hybrid system can simultaneously realize nanocatalytic therapy, chemotherapy and calcium overload. With the stabilization of liposomes, CCC is able to reach the tumor site smoothly. The CaCO3 shell first degrades in an acidic tumor environment, releasing Cur and Ca2+, and the pH value of the tumor is increased simultaneously. Then the exposed CSO catalyzes the Fenton-like reaction to convert H2O2 into ˙OH and enhances the cytotoxicity of curcumin (Cur) by catalytically oxidizing it to a ˙Cur radical. Curcumin not only induces the chemotherapy effect but also serves as a nucleophilic ligand and an electron donor in the catalytic system, enhancing the Fenton-like activity of CCC by electron transfer. In addition, calcium overload also amplifies the efficacy of ROS-based therapy. In vitro and in vivo results show that CCC exhibited an excellent synergistic tumor inhibition effect without any clear side effect. This work proposes a novel concept of nanocatalytic therapy/chemotherapy synergistic mechanism by the ligand-induced enhancement of Fenton-like catalytic activity, and inspires the construction of combined therapeutic nanoplatforms and multifunctional nanocarriers for drug and ion delivery in the future.

An “organic-inorganic” hybrid multilayer film for comprehensive support in soft and hard tissue regeneration after osteosarcoma resection

Three major complications often occur after osteosarcoma resection: large bone defects, infectious wounds, and tumor recurrence. In addition to conventional internal fixation and auto- or allografts, multifunctional supportive treatments are needed for limb reconstruction after tumor removal. With inspiration from the "organic-inorganic" hybrid concept, we developed a freestanding polyelectrolyte membrane (PEM) using a layer-by-layer (LBL) deposition of quaternized chitosan (QCS) and hyaluronic acid (HA), and with copper-doped laponite (CuLAP) intercalation. The CuLAP demonstrated photothermal conversion capabilities under near-infrared (NIR) light irradiation, and displayed glutathione (GSH)-depleted Fenton-like catalytic activity. The further engineered PEM possesses a "brick and mortar" structure with enhanced surface roughness and stiffness. The fusion of CuLAP-mediated GSH-depleted chemodynamic treatment (CDT) and moderate photothermal therapy (PTT) facilitated tumor ablation and bactericidal effects. Moreover, the continuous release of copper ions and silicates aided angiogenesis and osteogenesis, supporting the regeneration of both soft (skin) and hard (bone) tissues. This all-in-one platform offers a promising clinical tool for assisting tissue reconstruction after osteosarcoma resection.

Phospholipid membrane-protected photoelectrochemical chip: A specific test-to-treat platform for bacteria secreting pore-forming toxins with phosphatidylcholine receptor

Methicillin-resistant Staphylococcus aureus (MRSA) has emerged as a frequent cause of purulent skin and soft tissue infections. In this study, a test-to-treat chip was developed as an integrated platform for the highly sensitive detection and treatment of MRSA infections. By integrating arginine (Arg) ligand-doped FeMOFs onto TiO2 nanotube arrays (TNT), the resulting Arg-FeMOF-TNT chips exhibited excellent photoelectrochemical (PEC) activity under visible-light irradiation. As phosphatidylcholine (PC) specific pore-forming toxins (PC-PFTs) secreted by MRSA can specifically generate small holes in the phospholipid membrane (PM), the PM covered Arg-FeMOF-TNT photoactive surface can be re-exposed to the electrolyte in the presence of PC-PFTs and then reacted with electron donors in the electrolyte. On the basis of switch-on PEC signals, a detection limit as low as 6 CFU mL−1 was achieved for MRSA. Furthermore, benefitting from its intrinsic photocatalytic activity, the Fenton-like catalytic activity of FeMOFs, and the loaded Arg on the chip, abundant reactive oxygen species (ROSs) and nitric oxide (NO, arginine decomposition product) were generated in the bacterial microenvironment, resulting in the effective sterilization of MRSA. Importantly, the PM modification endow the chip to process good biosafety and remarkable antibacterial specificity towards MRSA. Animal experiment results further demonstrated that the chip can rapidly kill MRSA in wounds and promote wound healing under 532-nm-laser irradiation. This all-in-one chip offers a new method for the diagnosing bacteria and also provides new insight into the design of test-to-treat platforms for PC-PFTs bacteria.

An ultrasonic-assisted Synthesis, Characterization, and application of Nano-Fe3O4/TiO2 as nano-catalyst for the removal of organic dye by Like-Photo-Fenton reactions

In this research, Fe3O4 nanoparticles were synthesized via a simple co-precipitation method. Subsequently, these nanoparticles were used to synthesize TiO2-Fe3O4 nanocomposites via solvothermal ultrasonic-assisted method. Obtained nanomaterials Fe3O4 and TiO2-Fe3O4 were structurally characterized by UV–visible, XRD, and SEM-EDS. Synthesized nano-catalysts were tested as catalysis of organic dye degradation. Furthermore, an optimization study was conducted to evaluate selected TiO2-Fe3O4 nanocomposites to degrade Methylene Blue (MB) in an aqueous solution through Fenton-like reactions. Several experimental variables, including pH (from 2 to 8), H2O2 concentration (from 10-2 to 5.10-1M), catalyst amount (20 to 80 mg), and target organic compound concentrations, were tested in order to optimize the Fenton-like catalytic activity of the TiO2-Fe3O4 as a nano-catalyst to degrading MB under ambient light conditions (natural sunlight). The results showed that TiO2-Fe3O4 had an efficient degradation rate of up to 85% for MB at the optimal pH 3, H2O2 at 10-1M and 40 mg/L catalyst amount. Also, the results showed the good reusability of TiO2-Fe3O4 as a nanophotocatalyst. Also, based on the results of the scavenging agent experiments, hydroxyl radicals and superoxide radicals play an important role in methylene blue (MB) photodegradation. Finally, a possible mechanism for the photocatalytic degradation of MB was proposed. In this study, the synthesis and application of TiO2-Fe3O4 nanocomposite as a nano-catalyst in the Fenton-like oxidation process demonstrated a promising eco-friendly method for treating organic pollutants in water.

Full utilization of Cu single atoms on carbon nitride nanofibers for enhanced Fenton-like degradation of methylene blue

The utilization efficiency of single atoms is limited by the active sites being buried in support. To maximize atom utilization, Cu single atoms are anchored on the external surface of g-C3N4 nanofibers (CNNFs), which are fabricated by partial thermal decomposition and subsequent self-assembly in H2O. The abundant N and O-containing functional groups of CNNFs are vital for the loading of Cu. Benefited from the full utilization of Cu sites, CNNF-Cu exhibits excellent Fenton-like catalytic activity for Methylene Blue degradation. The reaction kinetic constant is more than 10 times higher than that of the traditional single-atom catalyst with Cu sites evenly distributed throughout the entire support. CNNF-Cu maintains most of its catalytic activity after five cycle tests, suggesting good stability. This work provides a convenient method to maximize the utilization of single metal atoms for catalytic applications.

Low H2O2 consumption Fenton-like catalysts for pollutant cleavage based on the construction of a dual reaction center

High energy consumption has seriously hindered the development of Fenton-like reactions for the removal of refractory organic pollutants in water. To solve this problem, we designed a novel Fenton-like catalyst (Cu-PAN3) by coprecipitation and carbon thermal reduction. The catalyst exhibits excellent Fenton-like catalytic activity and stability for the degradation of various pollutants with low H2O2 consumption. The experimental results indicate that the dual reaction centers (DRCs) are composed of Cu-N-C and Cu-O-C bridges between copper and graphene-like carbon, which form electron-poor/rich centers on the catalyst surface. H2O2 is mainly reduced at electron-rich Cu centers to free radicals for pollutant degradation. Meanwhile, pollutants can be oxidized by donating electrons to the electron-poor C centers of the catalyst, which inhibits the ineffective decomposition of H2O2 at the electron-poor centers. This therefore significantly reduces the consumption of H2O2 and reduces energy consumption.

Facilely Tuning the First-Shell Coordination Microenvironment in Iron Single-Atom for Fenton-like Chemistry toward Highly Efficient Wastewater Purification.

Precisely identifying the atomic structures in single-atom sites and establishing authentic structure-activity relationships for single-atom catalyst (SAC) coordination are significant challenges. Here, theoretical calculations first predicted the underlying catalytic activity of Fe-NxC4-x sites with diverse first-shell coordination environments. Substituting N with C to coordinate with the central Fe atom induces an inferior Fenton-like catalytic efficiency. Then, Fe-SACs carrying three configurations (Fe-N2C2, Fe-N3C1, and Fe-N4) fabricate facilely and demonstrate that optimized coordination environments of Fe-NxC4-x significantly promote the Fenton-like catalytic activity. Specifically, the reaction rate constant increases from 0.064 to 0.318 min-1 as the coordination number of Fe-N increases from 2 to 4, slightly influencing the nonradical reaction mechanism dominated by 1O2. In-depth theoretical calculations unveil that the modulated coordination environments of Fe-SACs from Fe-N2C2 to Fe-N4 optimize the d-band electronic structures and regulate the binding strength of peroxymonosulfate on Fe-NxC4-x sites, resulting in a reduced energy barrier and enhanced Fenton-like catalytic activity. The catalytic stability and the actual hospital sewage treatment capacity also showed strong coordination dependency. This strategy of local coordination engineering offers a vivid example of modulating SACs with well-regulated coordination environments, ultimately maximizing their catalytic efficiency.

Photothermal and Acid-Responsive Fucoidan-CuS Bubble Pump Microneedles for Combined CDT/PTT/CT Treatment of Melanoma.

Transdermal cancer therapy faces great challenges in clinical practice due to the low drug transdermal efficiency and the unsatisfactory effect of monotherapy. Herein, we develop a novel bubble pump microneedle system (BPMN-CuS/DOX) by embedding sodium bicarbonate (NaHCO3) into hyaluronic acid microneedles (MNs) loaded with fucoidan-based copper sulfide nanoparticles (Fuc-CuS NPs) and doxorubicin (DOX). BPMN-CuS/DOX can generate CO2 bubbles triggered by an acidic tumor microenvironment for deep and rapid intradermal drug delivery. Fuc-CuS NPs exhibit excellent photothermal effect and Fenton-like catalytic activity, producing more reactive oxygen species (ROS) by photothermal therapy (PTT) and chemodynamic therapy (CDT), which enhances the antitumor efficacy of DOX and reduces the dosage of its chemotherapy (CT). Simultaneously, DOX increases intracellular hydrogen peroxide (H2O2) supplementation and promotes the sustained production of ROS. BPMN-CuS/DOX significantly inhibits melanoma both in vitro and in vivo by the combination of CDT, PTT, and CT. In short, our study significantly enhances the effectiveness of transdermal drug delivery by constructing BPMNs and provides a promising novel strategy for transdermal cancer treatment with multiple therapies.

Effects and Mechanisms of Cu Species in Fe-MOFs on Fenton-Like Catalytic Activity and Stability.

Fe-based MOFs (Fe-MOFs) are deemed promising Fenton-like catalysts due to their well-developed pores and accessible active sites. However, their inferior catalytic activity, iron leaching, and low H2O2 utilization always hinder their application as Fe-based MOF catalysts. In this work, we manipulated the structure of Fe-oxo nodes in MIL-88B(Fe) via a CuI species substitution method, affording a mixed-valence (Cu-incorporated Fe-MOFs) with highly improved Fenton-like performance. It is found that the CuI serves as a shuttle to promote transfer between FeII/FeIII, inducing the formation of a larger amount of stable FeII sites, which was proven by experimental and DFT calculation results. A linear relationship was observed for the Fenton-like performance and the amount of CuI species for the catalysts. The corresponding value of the •OH formation is 2.17 eV for Cu-incorporated MIL-88B(Fe), which is significantly lower than that of MIL-88B(Fe) (2.69 eV). Meanwhile, the enriched CuI species suppress Fe species leaching during the catalytic reaction. The Fe-ion leakage of 0.4Cu@MIL-88B is very tiny (0.01-0.03 mg/L), significantly less than that of MIL-88B (2.00-3.02 mg/L). At the same time, H2O2 utilization for 0.4Cu@ MIL-88B(Fe) is 88%, which is almost 4.4 times that of pure MIL-88B(Fe). This work provides insights into the rational design of Fe-MOFs as promising Fenton-like catalysts for wastewater treatment.

Promoting •OH-dominant Fenton-like process over peracetic acid activation by ultrafine FeOx nanoclusters anchored carbonaceous nanosheets

Peracetic acid (PAA) has recently been considered a promising oxidant candidate for heterogeneous Fenton-like reactions; however, the main generation and contribution of organic radicals (R-O•) with unsatisfactory oxidation potential compromises wastewater decontamination efficiency. In this study, we demonstrate the rational design and synthesis of ultrafine FeOx nanocluster-anchored carbonaceous nanosheets (UFe-CN) for altering the PAA activation pathway from R-O• to •OH dominant process via in situ framework collapse carbonization of MIL-53(Fe). The constructed UFe-CN/PAA system effectively accelerated refractory micropollutant (e.g., p-nitrophenol (4-NP)) decomposition by the enhanced •OH formation (up to 65.24 µmol L−1) under a wide pH range (3.0–9.0), outperforming the benchmark iron-based catalyst counterparts by 4.2–10.8 times. This outstanding Fenton-like catalytic activity of UFe-CN is primarily attributed to the significant improvement in electron mitigation, ca. 49 times higher than that of its MIL-53(Fe) counterpart, for interface catalysis reactions triggered by iron species cycling. Furthermore, to facilitate adaptive engineering, the organic pollutant removal efficiency could be easily tuned by varying several key treatment factors, including the initial pH, PAA concentration, and UFe-CN dosage. More importantly, the excellent practicality of UFe-CN/PAA was demonstrated by systematically evaluating the impact of the water matrix, catalyst regeneration capability, and wastewater treatment efficiency. Overall, this study provides a significant understanding of •OH-dominated PAA activation and an effective catalyst development paradigm to facilitate the practical application of PAA-based Fenton-like oxidation.

Crystallinity engineering for overcoming the activity–stability tradeoff of spinel oxide in Fenton-like catalysis

A precise modulation of heterogeneous catalysts in structural and surface properties promises the development of more sustainable advanced oxidation water purification technologies. However, while catalysts with superior decontamination activity and selectivity are already achievable, maintaining a long-term service life of such materials remains challenging. Here, we propose a crystallinity engineering strategy to break the activity-stability tradeoff of metal oxides in Fenton-like catalysis. The amorphous/crystalline cobalt-manganese spinel oxide (A/C-CoMnOx) provided highly active, hydroxyl group-rich surface, with moderate peroxymonosulfate (PMS)-binding affinity and charge transfer energy and strong pollutant adsorption, to trigger concerted radical and nonradical reactions for efficient pollutant mineralization, thereby alleviating the catalyst passivation by oxidation intermediate accumulation. Meanwhile, the surface-confined reactions, benefited from the enhanced adsorption of pollutants at A/C interface, rendered the A/C-CoMnOx/PMS system ultrahigh PMS utilization efficiency (82.2%) and unprecedented decontamination activity (rate constant of 1.48min-1) surpassing almost all the state-of-the-art heterogeneous Fenton-like catalysts. The superior cyclic stability and environmental robustness of the system for real water treatment was also demonstrated. Our work unveils a critical role of material crystallinity in modulating the Fenton-like catalytic activity and pathways of metal oxides, which fundamentally improves our understanding of the structure-activity-selectivity relationships of heterogeneous catalysts and may inspire material design for more sustainable water purification application and beyond.

Preparation and Characterization of a Coordination Polymer Based on Iron (III)-Cyamelurate as a Superior Catalyst for Heterogeneous Fenton-Like Processes.

We report on a new iron (iii)-cyamelurate-based coordination polymer. The new material based on a heptazine derivative was prepared in aqueous medium and characterized by a variety of techniques including TGA, FTIR, XRD, HRTEM, and STEM. Due to the high structural stability of the complex in aqueous media, its heterogeneous Fenton-like catalytic activity was evaluated using a model molecule. The results obtained showed a high catalytic activity in both in basic and acid media. The pseudo-first-order rate constants normalized by iron(III) concentrations was approximately 1000 times higher than the result obtained for traditional heterogeneous catalysts based on iron(III) oxyhydroxides. The best observed catalytic activities were attributed to the increase in the binding sites of Fe3+ ions, in parallel with the increased exposure of the catalytic sites, leading to a higher atomic efficiency of the reaction.

Synergy between graphitized biochar and goethite driving efficient H2O2 activation: Enhanced performance and mechanism analysis

Due to the contradiction between attractive properties and undesirable Fenton-like catalytic performance of iron minerals, how to enhance their Fenton-like catalytic activity is a critical but challenging issue. Here, we took an eco-friendly approach to improve the Fenton-like catalytic capacity of goethite (α-FeOOH) by loading it on graphitized biochar (GBC), and the results indicated that the existence of GBC could successfully facilitate the oxytetracycline (OTC) removal. The degradation rate constant of α-FeOOH/GBC-10 composite was approximately 2.1 times higher than that of α-FeOOH. GBCs with different graphitization degrees were obtained by adjusting the pyrolysis temperature. Interestingly, the improvement of catalytic activity of α-FeOOH/GBC was well correlated with the graphitization degree of GBC, and the graphitized structures (sp2-C) and functional group (CO) in GBC could expedite the blocked Fe(III)/Fe(II) cycling by speeding up the electrons transfer from H2O2 to α-FeOOH and donating electrons to Fe(III). In addition, the electron spin resonance and quenching experiments demonstrated that OTC removal was attributed to the joint action of •OH, O2−, and 1O2. This study sheds light on the possible role of GBC in Fenton-like reactions based on iron minerals and thus, lays the groundwork for the rational construction of more efficient Fenton-like catalytic systems.

Cobalt/nitrogen co-carved carbon nanorod for efficient Fenton-like reaction: Degradation efficacy, reaction mechanism and singlet oxygen generation

• A CoNC Fenton-like catalyst can efficiently degrade organic pollutants. • It is confirmed that 1 O 2 is the dominant active species for degrading organics. • A CoN 2 C 2 ligands structure has the best catalytic activity for peroxymonosulfate activation. • The generation pathway of 1 O 2 is clearly clarified via DFT calculations. • Electrons can be easily transferred from the organics to peroxymonosulfate. The Fenton-like process shows promising potential to generate reactive oxygen species for the remediation of increasingly environmental pollutants. However, the slow development of high-activity catalysts with strong stability and low leaching of metal ions has greatly inhibited scale-up application of this technology. Here, cobalt (Co)/nitrogen (N) atom co-curved carbon nanorod (CoNC) containing highly uniform CoN x active sites is developed as a Fenton-like catalyst for the effective catalytic oxidation of various organics via peroxymonosulfate (PMS) activation with high stability. As confirmed by the experimental results, singlet oxygen ( 1 O 2 ) is the dominant active species for the degradation of the organics, with a proportion of 100%. Furthermore, density functional theory calculations indicate that CoN 2 C 2 is the most effective ligand structure with more negative adsorption energy for PMS and the shortest length Co–O bond, while the most reasonable generation pathway for 1 O 2 was CoN 2 C 2 –PMS → CoN 2 C 2 –OH* → 2O* → 1 O 2 . Further studies demonstrate that the electron can be transferred from the highest occupied molecular orbitals of the organics to the lowest unoccupied molecular orbitals of the PMS via CoN 2 C 2 action. In addition, the CoNC presents strong resistance to inorganic ions and natural organic matter in the Fenton-like catalysis process. The presence of CoN 2 C 2 active centre can significantly shorten the migration distance of the 1 O 2 generated from PMS activation, which further enhances the Fenton-like catalytic activity in terms of mineralising various organic contaminants with high efficiency over a wide pH range.

Preparation of 2D Polyaniline/MoO3- x Superlattice Nanosheets via Intercalation-Induced Morphological Transformation for Efficient Chemodynamic Therapy.

Organic intercalation of layered nanomaterials is an attractive strategy to fabricate organic/inorganic superlattices for a wide range of promising applications. However, the synthesis of 2D organic/inorganic superlattice nanosheets remains a big challenge. Herein, the preparation of 2D polyaniline/MoO3- x (PANI/MoO3- x ) superlattice nanosheets via intercalation-induced morphological transformation from MoO3 nanobelts, as efficient Fenton-like reagents for chemodynamic therapy (CDT), is reported. Micrometer-long MoO3 nanobelts are co-intercalated with Na+ /H2 O followed by the guest exchange with aniline monomer for insitu polymerization to obtain PANI/MoO3- x nanosheets. Intriguingly, the PANI intercalation can induce the morphological transformation from long MoO3 nanobelts to 2D PANI/MoO3- x nanosheets along with the partial reduction of Mo6+ to Mo5+ , and generation of rich oxygen vacancies. More importantly, thanks to the PANI intercalation-induced activation, the PANI/MoO3- x nanosheets exhibit excellent Fenton-like catalytic activity for generation of hydroxyl radical (·OH) by decomposing H2 O2 compared with the MoO3 nanobelts. It is speculated that the good conductivity of PANI can facilitate electron transport during the Fenton-like reaction, thereby enhancing the efficiency of CDT. Thus, the polyvinylpyrrolidone-modified PANI/MoO3- x nanosheets can function as Fenton-like reagents for highly efficient CDT to kill cancer cells and eradicate tumors.

Covalency competition triggers Fe-Co synergistic catalysis for boosted Fenton-like reactions

Fe-Co based oxides demonstrate excellent Fenton-like catalytic activity, but the intrinsic mechanism of Fe-Co synergy remains elusive. Here, we uncover the influence of covalency competition between Fe and Co on catalytic behaviors in peroxymonosulfate (PMS) activation. Theoretical and experimental analysis reveals that higher electron delocalization of octahedral Co (CoOh)-O unit and lower electron delocalization of FeOh-O unit boost electron transfer between Co and O species and transformation of SO5•− towards surface-bounded and free SO4•− instead of 1O2. With favorable covalency competition, electron transfer capability, active oxidizing species, (Co0.8Fe0.2)Oh-O unit exhibits superior activity with rate constant of 0.27 min−1, 254.7, 37.5 and 2.2 times of that in PMS, FeOh-O unit/PMS and CoOh-O unit/PMS systems, respectively, outperforming all the reported Fe-Co based oxides in removal of refractory pollutants. The improved insights into the origin of Fe-Co synergy advance the rational development of highly efficient catalytic oxidation systems for water decontamination.

Enhancing the Photocatalytic Degradation Efficiency of Dyes of Copper-Based Metal-Organic Frameworks through a Dimension-Induced Structural Strategy.

Photocatalytic degradation of pollutants is an effective environment purification strategy. Metal-organic frameworks (MOFs) have attracted extensive attention in the field of photocatalysis owing to their structural diversity, uniform cavity, and large specific surface area. However, poor electrical conductivity, light absorption, and water stability restrict their development. The tailorable structure of MOFs may effectively overcome these limitations. Herein, three Cu-based MOFs (complexes 1-3) with one-dimensional (1D), two-dimensional (2D), and three-dimensional (3D) structures, respectively, were successfully prepared by introducing different uncoordinated ligands and adjusting the ligand/metal salt ratio. Among them, complex 1 with a 1D chain was constructed as a typical J-type aggregation by π-π stacking interactions between adjacent naphthalene rings. This intermolecular aggregation mode enhances strong exciton coupling between conjugated rings, reduces the transition energy, expands the intrinsic light absorption edge, and provides a channel for electron transport, thus improving the charge-separation efficiency. As expected, complex 1 with a 1D chain structure exhibited excellent Fenton-like catalytic activity. The apparent reaction rates were 3.2 and 2.0 times higher than those of 2D and 3D MOFs, respectively.