Degradation Of Organic Pollutants Research Articles

Activation of Peroxymonosulfate by Co-Ni-Mo Sulfides/CNT for Organic Pollutant Degradation

To explore advanced oxidation catalysts, peroxymonosulfate (PMS) activation by Co-Ni-Mo/carbon nanotube (CNT) composite catalysts was investigated. A compound of NiCo2S4, MoS2, and CNTs was successfully prepared using a simple one-pot hydrothermal method. The results revealed that the activation of PMS by Co-Ni-Mo/CNT yielded an exceptional Rhodamine B decolorization efficiency of 99% within 20 min for the Rhodamine B solution. The degradation rate of Co-Ni-Mo/CNT was 4.5 times higher than that of Ni-Mo/CNT or Co-Mo/CNT, and 1.9 times as much than that of Co-Ni/CNT. Additionally, radical quenching experiments revealed that the principal active groups were 1O2, surface-bound SO4•−, and •OH radicals. Furthermore, the catalyst exhibited low metal ion leaching and favorable stability. Mechanism studies revealed that Mo4+ on the surface of MoS2 participated in the oxidation of PMS and the transformation of Co3+/Co2+ and Ni3+/Ni2+. The synergism between MoS2 and NiCo2S4 reduces the charge transfer resistance between the catalyst and solution interface, thus accelerating the reaction rate. Interconnected structures composed of metal sulfides and CNTs can also enhance the electron transfer process and afford sufficient active reaction sites. Our work provides a further understanding of the design of multi-metal sulfides for wastewater treatment.

Geochip 5.0 insights into the association between bioleaching of heavy metals from contaminated sediment and functional genes expressed in consortiums.

The heavy metal contamination in river and lake sediments endangers aquatic ecosystems. Herein, the feasibility of applying different exogenous mesophile consortiums in bioleaching multiple heavy metal-contaminated sediments from Xiangjiang River was investigated, and a comprehensive functional gene array (GeoChip 5.0) was used to analyze the functional gene expression to reveal the intrinsic association between metal solubilization efficiency and consortium structure. Among four consortiums, the Acidithiobacillus thiooxidans and Leptospirillum ferrooxidans consortium had the highest solubilization efficiencies of Cu, Pb, Zn, and Cd after 15days, reaching 50.33, 29.93, 47.49, and 79.65%, while Cu, Pb, and Hg had the highest solubilization efficiencies after 30days, reaching 63.67, 45.33, and 52.07%. Geochip analysis revealed that 31,346 genes involved in different biogeochemical processes had been detected, and the systems of 15days had lower proportions of unique genes than those of 30days. Samples from the same stage had more genes overlapping with each other than those from different stages. Plentiful metal-resistant and organic remediation genes were also detected, which means the metal detoxification and organic pollutant degradation had happened with the bioleaching process. The Mantel test revealed that Pb, Zn, As, Cd, and Hg solubilized from sediment influenced the structure of expressed microbial functional genes during bioleaching. This work employed GeoChip to demonstrate the intrinsic association between functional gene expression of mesophile consortiums and the bioleaching efficiency of heavy metal-contaminated sediment, and it provides a good reference for future microbial consortium design and remediation of river and lake sediments.

Excellent efficiency and cycling performance for organic pollutant degradation using Sb2S3 tubular photocatalysts with heterojunction structures

Excellent efficiency and cycling performance for organic pollutant degradation using Sb2S3 tubular photocatalysts with heterojunction structures

Prediction of the degradation of organic pollutants by metal-activated peracetic acid using machine learning

This study utilized machine learning (ML) to predict the kinetic constant (k) of pollutant degradation by using metal-activated peracetic acid (PAA) and evaluated the performance of three different ML models. The Random Forest (RF) model obtained by parameter optimization had the best prediction performance. The study delved into the significance of various characteristics, and three catalogues (reaction conditions, properties of metal and pollutants) were considered. The results revealed that the density (ρ) and polar surface area (PSA) of pollutants, pH, humic acid (HA), metal ionization energy and atomic radius of metal (r) exhibited the most pronounced characteristic effects. Among them, ρ, PSA and r positively affected k. While HA, pH and ionization energy had negative effects. Based on the results, the metals met ionization energy < 710KJ/mol and r > 0.165nm (e.g., Ru, Mo, Ti and Tc) were suggested to be the catalyst to activate PAA. And pH < 8 was conducive to the reaction. Furthermore, the metal-activated PAA would be efficient to eliminate organic pollutants with the pollutant density > 1.6g/cm3 and PSA > 180 (e.g., tetracycline, macrocyclic lipids and antibiotics). The relevant conclusions and the determination of the optimal ML model could provide reference for future research.

Photonic crystal-assisted sub-bandgap photocatalysis via triplet-triplet annihilation upconversion for the degradation of environmental organic pollutants

This study explores novel approaches to enhance photocatalysis efficiency by introducing a photonic crystal (PC)-enhanced, multi-layered sub-bandgap photocatalytic reactor. The design aims to effectively utilize sub-bandgap photons that might otherwise go unused. The device consists of three types of layers: (1) two polymeric triplet-triplet annihilation upconversion (TTA-UC) layers converting low-energy green photons (λEx = 532 nm, 2.33 eV) to high-energy blue photons (λEm = 425 nm, 2.92 eV), (2) a platinum-decorated WO3 layer (Eg = 2.8 eV) serving as a visible-light photocatalyst, and (3) a PC layer optimizing both TTA-UC and photocatalysis. The integration of the PC layer resulted in a 1.9-fold increase in UC emission and a 7.9-fold enhancement in hydroxyl radical (•OH) generation, achieved under low-intensity sub-bandgap irradiation (17.6 mW cm–2). Consequently, the combined layered structure of TTA/Pt-WO3/TTA/PC achieved a remarkable 38.8-fold improvement in •OH production, leading to outstanding degradation capability for various organic pollutants (e.g., 4-chlorophenol, bisphenol A, and methylene blue). This multi-layered sub-bandgap photocatalytic structure, which uniquely combines TTA-UC and PC layers, offers valuable insights into designing efficient photocatalytic systems for future solar-driven environmental remediation.

Magnetic-supported catalyst derived from red mud-based Fe-Co PBA for efficient degradation of organic pollutants by activating peroxymonosulfate under visible light

To alleviate the environmental pressure caused by the continuous accumulation of solid waste red mud (RM) and organic pollutants, we developed a magnetic-supported catalyst derived from RM-based Fe-Co Prussian blue analogues (RM-Co PBA-D) using RM as the iron source and carrier. Then, the catalyst was used to activate peroxymonosulfate (PMS) under visible light for the degradation of tetracycline (TC) and rhodamine B (RhB). Due to the superior dispersion, strong visible light response, and high photo-generated carrier separation efficiency of the RM-Co PBA-D, the RM-Co PBA-D/PMS/Vis system could completely degrade both TC (10 mg/L) and RhB (20 mg/L) in 30 min, with mineralization efficiencies as high as 70.12 % and 60.59 %, respectively. Several reactive oxygen species (ROS) such as SO4⋅−, ⋅OH−, ⋅O2−, 1O2, and h+ were involved in the degradation process, with SO4⋅− and 1O2 playing a dominant role. More importantly, except for the production of ROS, the regeneration of active sites (Co2+/Fe2+) mediated by photo-generated carriers was also a critical factor in enhancing the removal of organic pollutants. In addition, the constructed system demonstrated significant potential for practical applications, which was attributed to the stable structure and catalytic performance of the catalyst as well as the strong ability of the system to resist interference by impurity anions and detoxify organic pollutants.

Enhanced Photocatalytic Degradation by the Preparation of a Stable La-Doped FeTiO3 Photocatalyst: Experimental and DFT Study.

The rapid photocarrier recombination limits the photocatalytic activity of iron titanate (FeTiO3) to be further improved. Developing novel approaches to inhibit the rapid recombination rate of the FeTiO3 photocatalysts is crucial for efficiently degrading pollutants in wastewater. Rare earth ions, with unique electron dispositions and large ion radii, could effectively inhibit photocarrier recombination. Herein, novel lanthanum (La)-doped FeTiO3 photocatalysts were designed and successfully synthesized. The photocatalytic performance of the 12 mol % La/FeTiO3 photocatalyst was superior in degrading tetracycline hydrochloride (TCH), methylene blue (MB), and brilliant blue (BB). These degradation rate constants (k) were 0.12358, 0.01357, and 0.03064 L mg-1 min-1, respectively, which were 12.83, 1.61, and 7.78 times that of pure FeTiO3. The photoelectronic tests and density functional theory (DFT) calculations revealed that the La 4f orbital forms an impurity energy level in the conduction band of FeTiO3. This level narrows the bandgap and acts as an electron acceptor, capturing photoexcited electrons and inhibiting the rapid recombination of photoexcited electron-hole pairs in FeTiO3. This work enhances the potential of FeTiO3 in the photocatalysis field and provides important insights into the efficient degradation of organic pollutants in wastewater.

Fe3O4/ZnO/L-lysine functionalized graphene oxide a promising nanocomposite with double Z-scheme visible photocatalytic and dark catalytic activity for water remediation

Developing multifunctional catalysts for efficient pollutant degradation in dark and visible light conditions represents a significant advancement in water remediation technology. This study reports the synthesis of a novel Fe3O4/ZnO/Lys-rGO nanocomposite via environmentally friendly methods that exhibit catalytic-photocatalytic activity for efficient degradation of organic pollutants. The synergistic effect of compositing Lys-rGO, a bio-organic component with a narrow band gap (1.08 eV), into the Fe3O4/ZnO inorganic composite induces a double Z-scheme mechanism by providing two pathways for effective charge separation in the visible photocatalytic activity of the nanocomposite. Additionally, the stored electrons in the very conductive Lys-rGO layers offer active sites for the catalytic activity of the nanocomposite in the dark. Meanwhile, ZnO generates reactive oxygen species (ROS) through surface oxygen vacancies, further contributing to the nanocomposite’s dark catalytic activity. The degradation of various organic pollutants (Methylene Blue, Tetracycline, Ciprofloxacin, Rhodamine B, and their mixture), as well as Congo Red, with low catalyst dosage and visible light irradiation time, demonstrates the high performance and versatility of this nanocomposite. This research highlights the potential of Lys-rGO in compositing with semiconductors to design multifunctional catalysts for cost-effective sustainable water purification technologies.

Enhanced photocatalytic efficiency of BaTiO3 augmented by ZnS nanospheres via Type-II heterojunction for methyl orange degradation

The degradation of organic pollutants is significantly influenced by the recombination of photogenerated electron–hole pair, electron transfer and surface area of a photocatalyst. Barium titanate (BaTiO3) exhibits low photocatalytic activity due to the rapid recombination of photoinduced charge carriers. Hence, the photocatalytic performance of BaTiO3 (BTO) nanoparticles was improved by the construction of heterostructure with the addition of ZnS. BaTiO3 and ZnS were prepared using solid-state metathesis (SSM) and hydrothermal methods, respectively. Subsequently, a series of [(1-x)BaTiO3/(x)ZnS, x = 10, 30, 50 and 70 wt%] heterostructures were successfully constructed through a simple calcination method using pre-prepared BaTiO3 and ZnS. The XRD, FTIR, Raman, XPS and HRTEM analyses revealed the formation of heterostructure between the BTO and ZnS. The positron annihilation lifetime spectroscopy (PALS) results suggest the existence of defects within the materials. To explore the photocatalytic activity, the photodegradation of methyl orange (MO) dye was carried out under UV light illumination for 3 h. Among all the compositions, the heterostructure 70 BaTiO3/30 ZnS (BTZS(70-30)) demonstrated remarkable photocatalytic activity (91.38 %) which is 5.3 times higher than the pristine BTO (17.16 %). The improved photocatalytic activity of heterostructures may result from the effective charge carrier separation facilitated by the type –II band alignment structure between BTO and ZnS, as well as surface defects like oxygen (Vo), and sulphur (Vs) vacancies. The lowest photoluminescence of BTZS (70-30) clearly substantiated the observed high photocatalytic activity. The scavenger outcomes validated that superoxide radicals (•O2−) and holes (h+) played predominant role in the degradation of MO and a detailed explanation was provided for the plausible mechanism.

In Situ Synthesis of Exfoliated Ni(OH)2 Nanosheets and AgNPs-Embedded Functionalized Polyindole-Based Trinary Hybrid Microspheres: A Z-Scheme Photocatalyst for the Sunlight-Driven Degradation of Organic Pollutants with Enhanced Antibacterial Efficacy.

Advancing a facile one-pot synthetic approach for the fabrication of a hybrid heterojunction photocatalyst remains a significant challenge in research pursuits. Herein, a microsphere-like trinary hybrid nanocomposite has been synthesized (NH/PIn/MAA/Ag). It comprises exfoliated single- and a few-layered Ni(OH)2 (NH nanosheets), mercaptoacetate-functionalized polyindole (PIn/MAA), and Ag nanoparticles (AgNPs) through an in situ approach. The formation mechanism is based on the exfoliation of stacked Ni(OH)2 multilayers [i.e., Ni(OH)2 microflowers] and stabilization of NH nanosheets through host-guest formation of PIn/MAA, followed by the adsorption-reduction of Ag+ ions in a one-pot reaction at low temperature. Surface morphological analyses of hybrid nanocomposite microspheres have exhibited that highly dense Ni(OH)2 microflowers have been transformed into low-density layered forms (NH nanosheets) within the polymeric platform (PIn/MAA) with deposited AgNPs. An interfacial heterojunction has been developed between the components in the depletion region, leading to an improvement in photocatalytic efficiency through a synergistic effect over the components for charge separation and transfer through the heterojunction interface via solid-state mediator Ag-based Z-scheme charge transfer dynamics. The superior photocatalytic degradation of tetracycline (98.2%) by trinary hybrid microspheres can be attributed to the deteriorated recombination rate of electron-hole pairs with reduced charge transfer resistance of the heterojunction in the photocatalyst, as obvious from photoluminescence, electrochemical impedance spectroscopy, chronoamperometry, and time-resolved photoluminescence (TRPL) analyses. Moreover, the antibacterial properties of microspheres against Bacillus pumilus (Gram-positive) and Escherichia coli (Gram-negative) bacteria have validated their potential as promising materials for the overall purification of aquatic systems.

Selective degradation of pollutants in the Mn-NG/PMS system: The crucial role of surface reactive Mn(IV) species

The combination of transition metal oxides with carbon-based materials is a promising strategy for constructing efficient catalysts for peroxymonosulfate (PMS) activation to degrade aqueous organic contaminants. However, the complex heterostructure of the composites often hinders the identification of the actual reactive species responsible for pollutant degradation. In this study, we integrate Mn3O4 into N-doped graphite (NG) to elucidate the mechanisms involved in the Mn-NG composite mediated PMS activation process. The Mn-NG/PMS system shows excellent performance in oxidizing bisphenol A (BPA) over a wide pH range (3.4 to 9.4) and in the presence of co-existing substrates. Mn sites in Mn3O4 are responsible for the activation of PMS, and the NG matrix enhances the dispersion of Mn in the Mn-NG composite. Multiple experimental results indicate that free radicals (i.e., hydroxyl radicals (HO•) and sulfate radicals (SO4•−)) are not generated, and surface reactive Mn(IV) is proposed as the primary reactive species for BPA oxidation. This study provides new insights into understanding the role of Mn oxides in carbon-based composites in PMS activation for degradation of organic pollutants.

Highly selective regulation of non-radical and radical mechanisms by Co cubic assembly catalysts for peroxymonosulfate activation

Peroxymonosulfate (PMS) activation on efficient catalysts is a promising strategy to produce sulfate radical (SO4−) and singlet oxygen (1O2) for the degradation of refractory organic pollutants. It is a great challenge to selectively generate these two reactive oxygen species, and the regulation mechanism from non-radical to radical pathway and vice versa is not well established. Here, we report a strategy to regulate the activation mechanism of PMS for the selective generation of SO4− and 1O2 with 100 % efficiency by sulfur-doped cobalt cubic assembly catalysts that was derived from the Co-Co Prussian blue analog precursor. This catalyst showed superior catalytic performance in activating PMS with normalized reaction rate increased by 87 times that of the commercial Co3O4 nanoparticles and had much lower activation energy barrier for the degradation of organic pollutant (e.g., p-chlorophenol) (18.32 kJ⋅mol−1). Experimental and theoretical calculation results revealed that S doping can regulate the electronic structure of Co active centers, which alters the direction of electron transfer between catalyst and PMS. This catalyst showed a strong tolerance to common organic compounds and anions in water, wide environmental applicability, and performed well in different real-water systems. This study provides new opportunities for the development of metal catalyst with metal-organic frameworks structure and good self-regeneration ability geared specifically towards PMS-based advanced oxidation processes applied for water remediation.

Nitrogen-doped bismuth ferrite nanozymes: Tailored electronic structure for organic pollutant degradation

The insufficient catalytic activity and non-recyclability of nanozymes are major obstacles for nanozyme-mediated water purification. Since electronic transfer is the basic essence of catalysis-mediated redox reactions, this research reveals that meticulous tuning of the electronic structure of magnetic bismuth ferrite (BiFeO3) through nitrogen doping, allows for excellent performance in organic pollutants degradation in water (including dyestuff and antibiotics), along with magnet separation-mediated recyclability. Mechanically speaking, nitrogen-doping rational optimize their peroxidase-like activity by increasing the electron density of the Fe-N active center, meanwhile, the tailored bandgap significantly enhances the full-spectrum absorption, especially in the near-infrared region (NIR). Consequently, a light-enhanced N-doped BiFeO3 nanozyme has been engineered to generate excessive reactive oxygen species (14.63-fold in total) for pollutants degradation with recyclable capacity, 94.27% for Methylene Blue and over 60% for multiple antibiotics. This study underscores the efficacy of fine-tuning the electronic structure in enhancing the catalytic performance of nanozymes for organic pollutants removing.

Tetragonal/orthorhombic phase Bi2WO6 homojunction for photoelectrochemical degradation of rhodamine B with high efficiency

Photoelectrochemical (PEC) degradation of organic pollutants to CO2 and H2O is a promising strategy to solve the growing environmental problems. Bismuth tungstate (Bi2WO6) has attracted much attention due to its good chemical stability and moderate conduction band valence band position. However, the PEC activity of Bi2WO6 catalysts is greatly limited due to its rapidly complex electron-hole. This article reports a rational low-cost design that successfully prepares tetragonal/orthorhombic Bi2WO6 homojunction on FTO conductive glass substrates through a simple two-step solvothermal method, significantly enhancing the PEC performance. The study investigated the effectiveness of photoelectrochemical degradation of the recalcitrant organic pollutant Rhodamine B (RhB) and conducted an in-depth exploration of the photoelectrocatalytic reaction process and mechanism. The experimental results indicate that the homojunction achieves a degradation rate of up to 100 % for the recalcitrant organic pollutant RhB within 30 minutes, significantly surpassing that of single-phase Bi2WO6, and at the same time the sample maintains good stability after five cycles of operation. Further analysis of the capture experiments indicates that holes (h+) and superoxide radicals (·O2⁻) are the primary active species responsible for RhB degradation. This study not only provides new insights into the design of high-efficiency photoelectrode, but also offers new solutions for environmental pollution control.

Activation of H2O2-HCO3- by Ca2Co2O5 for pollutant degradation.

The bicarbonate-activated hydrogen peroxide (BAP) system is widely studied for organic pollutant degradation in wastewater treatment. Ca2Co2O5, a heterogeneous catalyst containing multivalent cobalt including Co(II) and Co(III), was herein investigated as a BAP activator, and Acid Orange 7 (AO7) was used as a model pollutant. Ca2Co2O5 exhibited good activation performance. The degradation rate and the initial rate constant of the Ca2Co2O5-activated BAP system were 5.4 and 11.2 times as high as the BAP system, respectively. The removal rate of AO7 reached 90.9% in 30min under optimal conditions (AO7 20mg/L, Ca2Co2O5 0.2g/L, H2O2 1mM, NaHCO3 5mM, pH 8.5, 25℃). The Ca2Co2O5 catalyst exhibited good stability and recyclability, retaining 85% of AO7 removal rate in the fifth run. Compared to the BAP system, a lower dosage of H2O2 was required and a higher initial concentration of pollutants allowed for effective degradation in the Ca2Co2O5-BAP system. X-ray photoelectron spectroscopy was used to analyze the catalytic mechanism. The analysis showed that the good catalytic performance of Ca2Co2O5 attributes to its high proportion of oxygen vacancies and Co(III) species, and the presence of Ca. The active species O2•-, •OH, and 1O2 are responsible for the degradation, as indicated by the quenching experiments. The degradation mechanism of AO7 was speculated based on UV-Vis spectral analysis and the identification of degradation intermediates. The azo form, naphthalene and benzoic rings in the AO7 structure are destroyed in the decomposition. This research provides a feasible approach to designing effective and reusable BAP activators for pollutant degradation in wastewater treatment.

Eco-Friendly g-C3N4/Carboxymethyl Cellulose/Alginate Composite Hydrogels for Simultaneous Photocatalytic Degradation of Organic Dye Pollutants.

The presented study was focused on the simple, eco-friendly synthesis of composite hydrogels of crosslinked carboxymethyl cellulose (CMC)/alginate (SA) with encapsulated g-C3N4 nanoparticles. The structural, textural, morphological, optical, and mechanical properties were determined using different methods. The encapsulation of g-C3N4 into CMC/SA copolymer resulted in the formation of composite hydrogels with a coherent structure, enhanced porosity, excellent photostability, and good adhesion. The ability of composite hydrogels to eliminate structurally different dyes with the same or opposite charge properties (cationic Methylene Blue and anionic Orange G and Remazol Brilliant Blue R) in both single- and binary-dye systems was examined through adsorption and photocatalytic reactions. The interactions between the dyes and g-C3N4 and the negatively charged CMC/SA copolymers had a notable influence on both the adsorption capacity and photodegradation efficiency of the prepared composites. Scavenger studies and leaching tests were conducted to gain insights into the primary reactive species and to assess the stability and long-term performance of the g-C3N4/CMC/SA beads. The commendable photocatalytic activity and excellent recyclability, coupled with the elimination of costly catalyst separation requirements, render the g-C3N4/CMC/SA composite hydrogels cost-effective and environmentally friendly materials, and strongly support their selection for tackling environmental pollution issues.

Scalable synthesis of Bi2O2S nanoplates with large piezoelectric potential induced by a built-in electric field in a [Bi2O2]2+ layer for the degradation of organic contaminants.

2D piezoelectric catalysts with strong piezoresponse and high piezoelectric potential have valuable applications in catalytic degradation of organic pollutants and antibiotics, but the development of novel nanomaterials with powerful piezopotential still remains a serious challenge. Bismuth oxysulfide (Bi2O2S) nanosheets possessing large piezoelectric potentials were prepared using a low-heating solid-state chemical reaction and used for the first time for piezoelectric catalysis in this work. Moreover, Bi2O2S nanosheets can degrade pollutants universally, and the degradation efficiencies of methyl blue and rhodamine B are as high as 97.7% and 92.9% within 60 min under ultrasonication, respectively, which is superior to most piezoelectric materials reported in the literature.

One-step formation of synergistic ZnO/SnO2 composite nanostructures derived from annealing of crystalline ZnSn(OH)6 nanocubes for enhanced catalytic degradation of organic pollutants

Binary metal oxides/hydroxides derived primary metal oxide composites have a pivotal role in diverse applications because of the beneficial interfacial contact, good synergism, high porous nature, and high stability. The current work deals with the derived ZnO/SnO2 composite nanostructures from post-annealing crystalline ZnSn(OH)6 (ZTO-RT) nanocubes, initially synthesized via a single-step hydrothermal synthesis method. First, the pristine ZTO-RT is synthesized @ 180 °C in a hydrothermal autoclave. Further, the transformation of ZTO-RT to ZnO/SnO2 composite nanostructures is performed at two different annealing temperatures of 500 °C (ZTO-DV-500) and 750 °C (ZTO-DV-750) in the vacuum. The respective samples' physical characterization was studied and compared using various analytical techniques. The X-ray diffraction analysis affirms the amorphous nature of ZTO-DV-500 and the poly-crystalline nature of ZTO-DV-750. The nanocube morphologies of the samples are retained even at high-temperature sintering. The existence of metal-oxygen bonds on the surface of the ZnO/SnO2 composite is sustained by X-ray photoelectron spectroscopy. ZTO-DV-750 has larger pores (pore volume - 0.091 cm3 g−1) than the ZTO-DV-500 (0.051 cm3 g−1). In the presence of NaBH4 aqueous solution, the enhanced rhodamine B dye degradations of ZTO-DV-750 are observed. At low RhB concentrations (5 mg L−1), the ZTO-DV-500 and ZTO-DV-750 rate constants are determined to be 0.099 and 0.156 min−1, respectively, while at high concentration (10 mg L−1), these values are 0.043, and 0.091 min−1. Therefore, the ZTO-DV-750 composite has shown potent catalytic activity with NaBH4 over ZTO-DV-500 to decolourise organic dyes.

Coupling Cu Coordination Polymers with CdS Forming an S-Scheme Heterojunction for Rapid Charge Separation and High Photocatalytic Activity.

Energy and the environment are significant impacting factors for the future development of humankind. In order to improve the corrosion resistance of CdS and decrease the recombination of photogenerated carriers, a novel Cu-CPs@CdS heterojunction with high efficiency mesopores was constructed by a simple hydrothermal method. The effective interfacial contact formation between nano-CdS and Cu-CPs promotes the transfer of photogenerated carriers while exhibiting a high spatial separation rate of charges. The photocatalytic performance of the heterojunction was evaluated by the photocatalytic degradation of organic pollutants and photocatalytic hydrogen generation. The photocatalytic degradation of ciprofloxacin (CIP) could reach 90.34%, and the hydrogen generation was high as 9227.82 μmol·g-1 under simulated sunlight irradiation. The boosted photocatalytic activity of Cu-CPs@CdS results from (i) the formation of coordination bonds, which not only enhanced the stability of heterojunctions but also provided a path for photogenerated carrier migration, (ii) integrating Cu-CPs, which provided more active sites, and (iii) the matched energy band structure between CdS and Cu-CPs that promoted speedy S-scheme interfacial charge-transfer pathways, culminating in efficient photogenerated charge separation and transfer. This research offered a fresh tactic to restrict photocorrosion and enhance the production of photocatalytic H2 over CdS-based catalysts.

Crystal phase-driven performance of MnO2 in aqueous phase low-temperature thermal catalysis: Synergistic interactions between Mn3+ and surface lattice oxygen

Catalytic oxidation at mild conditions is crucial for mitigating the high pressure and high temperature challenges associated with current catalytic wet air oxidation (CWAO) technologies in wastewater treatment. Among potential materials for catalytic oxidation reactions, polycrystalline MnO2 existed in natural minerals holds considerable promise. However, the relationships between different crystal phases of MnO2 and their catalytic activity sources in aqueous phase remain uncertain and subject to debate. In this research, we synthesized various MnO2 crystal phases, comprising α-, β-, δ-, γ-, ε-, and λ-MnO2, and assessed their catalytic oxidation efficiency during low-temperature heating for treatment of organic pollutants. Our findings demonstrate that λ-MnO2 exhibits the highest catalytic activity, followed by δ-MnO2, γ-MnO2, α-MnO2, ε-MnO2, and β-MnO2. The variations in catalytic activity among different MnO2 are attributed to variances in their oxygen vacancy abundance and redox activity. Furthermore, we identified the primary active species, which include Mn3+ and superoxide radicals (•O2–) generated by surface lattice oxygen of MnO2. This research highlights the critical role of crystal phases in influencing oxygen vacancy content, redox activity, and overall catalytic performance, providing valuable insights for the rational design of MnO2 catalysts tailored for effective organic pollutant degradation in CWAO applications.