Why is Rose Bengal More Phototoxic to Fibroblasts In Vitro Than In Vivo?

Photosensitized protein cross‐linking has been recently developed to seal wounds and strengthen tissue. Although the photosensitizing dye, Rose Bengal (RB), is phototoxic to cultured cells, cytotoxicity does not accompany RB‐photosensitized tissue repair in vivo. We investigated whether the environment surrounding cells in tissue or the high irradiances used for photo–cross‐linking inhibited RB phototoxicity. Fibroblasts (FB) grown within collagen gels to mimic a tissue environment and monolayer cultured FB were treated with RB (0.01–1 mm ) and the high 532 nm laser irradiances used in vivo for tissue repair (0.10–0.50 W cm^?2). Monolayer FB were substantially more sensitive to RB photosensitization: the LD₅₀ was >200‐fold lower than that in collagen gels. Collagen gel protection was associated with increased Akt phosphorylation, a prosurvival pathway. RB phototoxicity in collagen gels was 25‐fold greater at low (0.030 W cm^?2) that at high (0.50 W cm^?2) irradiances. Oxygen depletion at high irradiance only partially accounted for the irradiance dependence of phototoxicity as replacing air with nitrogen only increased the LD₅₀ by four‐fold in monolayers. These results indicate that the lack of RB phototoxicity during in vivo tissue repair results from upregulation of prosurvival pathways in tissue cells, oxygen depletion and irradiance‐dependent RB photochemistry.     

Rose Bengal‐Sensitized Photooxidation of the Dipeptides l‐Tryptophyl‐l‐Phenylalanine,l‐Tryptophyl‐l‐Tyrosine and l‐Tryptophyl‐l‐Tryptophan: Kinetics,Mechanism and Photoproducts¶

The Rose Bengal‐sensitized photooxidations of the dipeptides l ‐tryptophyl‐l ‐phenylalanine (Trp‐Phe), l ‐tryptophyl‐l ‐tyrosine (Trp‐Tyr) and l ‐tryptophyl‐l ‐tryptophan (Trp‐Trp) have been studied in pH 7 water solution using static photolysis and time‐resolved methods. Kinetic results indicate that the tryptophan (Trp) moiety interacts with singlet molecular oxygen (O₂(¹Δ_g)) both through chemical reaction and through physical quenching, and that the photooxidations can be compared with those of equimolecular mixtures of the corresponding free amino acids, with minimum, if any, influence of the peptide bond on the chemical reaction. This is not a common behavior in other di‐ and polypeptides of photooxidizable amino acids. The ratio between chemical (k_r) and overall (k_t) rate constants for the interaction O₂(¹Δ_g)‐dipeptide indicates that Trp‐Phe and Trp‐Trp are good candidates to suffer photodynamic action, with k_rlk_t values of 0.72 and 0.60, respectively (0.65 for free Trp). In the case of Trp‐Tyr, a lower k_rlk_t value (0.18) has been found, likely as a result of the high component of physical deactivation of O₂(¹Δ_g) by the tyrosine moiety. The analysis of the photooxidation products shows that the main target for O₂(¹Δ_g) attack is the Trp group and suggests a much lower accumulation of kynurenine‐type products, as compared with free Trp. This is possibly because of the occurrence of another accepted alternative pathway of oxidation that gives rise to 3a‐oxidized hydrogenated pyrrolo[2,3‐b]indoles.     

ENHANCEMENT OF THE SENSITIVITY OF RADIATIVE and NON-RADIATIVE DETECTION TECHNIQUES IN THE STUDY OF PHOTOSENSITIZATION BY WATER SOLUBLE SENSITIZERS USING A REVERSE MICELLE SYSTEMS*,†

The study of photosensitization processes in aqueous solution is complicated by the unsuit-ability of water as solvent for the commonly used techniques for monitoring radiative and non-radiative relaxation processes. The infrared luminescence method is hampered by the relatively weak intensity of emission and short lifetime of singlet molecular oxygen, O₂(¹Δ_g), in water. Photoacoustic and photothermal detection of the dominant non-radiative relaxation process for O₂(¹Δ_g) is also inhibited by the unfavorable physico-chemical properties of water which reduce the sensitivities of these techniques for the study of sensitizers in aqueous with respect to non-aqueous media. Such problems have been alleviated by incorporating the sensitizer in the aqueous core of aerosol OT reverse micelles. It is demonstrated that the sensitivity of both radiative and non-radiative detection depends not on the local environment of the sensitizer but on the overall composition of the medium, which, in the case of reverse micelle solutions, is predominantly hydrocarbon. This produces a 4.5 and 6-fold enhancement of the sensitivity of luminescence and optoacoustic detection, respectively, in comparison to purely aqueous solution. The utility of the method is demonstrated for Rose Bengal, where quantum yields of intersystem crossing (φ_isc) of 0.78 (LIOAC) and singlet oxygen generation (φ_δ) of 0.81 (LIOAC) and 0.80 (TRLD) were measured. Phenazine was also studied for comparative purposes and to corroborate values obtained for Rose Bengal.     

Dye Binding Characteristics of N,N′‐Methylene‐bis‐acrylamide (NNMBA)‐Crosslinked Polyacrylamide‐Supported Amine and its Photooxidizing Ability

The dye binding characteristics of 8 mol% NNMBA‐crosslinked polyacrylamide‐supported amine is investigated with Rose Bengal (RB), Methyl Orange (MO), Methylene Blue (MB) and Methyl Red (MR). The influence of the concentration of dye solution on dye binding, time course of dye binding and characterization were explored. It is observed that binding is higher in the case of Rose Bengal and dye binding depends on the polarity, as well as the size of the dye molecule. The photooxidation property of polymer bound RB was investigated towards the oxidation of benzoin to benzil. RB bound polymer acts as an efficient heterogenous photooxidizing agent.     

Two‐Dimensional Cobalt‐/Nickel‐Based Oxide Nanosheets for High‐Performance Sodium and Lithium Storage

Two‐dimensional (2D) nanomaterials are one of the most promising types of candidates for energy‐storage applications due to confined thicknesses and high surface areas, which would play an essential role in enhanced reaction kinetics. Herein, a universal process that can be extended for scale up is developed to synthesise ultrathin cobalt‐/nickel‐based hydroxides and oxides. The sodium and lithium storage capabilities of Co₃O₄ nanosheets are evaluated in detail. For sodium storage, the Co₃O₄ nanosheets exhibit excellent rate capability (e.g., 179 mA h g^?1 at 7.0 A g^?1 and 150 mA h g^?1 at 10.0 A g^?1) and promising cycling performance (404 mA h g^?1 after 100 cycles at 0.1 A g^?1). Meanwhile, very impressive lithium storage performance is also achieved, which is maintained at 1029 mA h g^?1 after 100 cycles at 0.2 A g^?1. NiO and NiCo₂O₄ nanosheets are also successfully prepared through the same synthetic approach, and both deliver very encouraging lithium storage performances. In addition to rechargeable batteries, 2D cobalt‐/nickel‐based hydroxides and oxides are also anticipated to have great potential applications in supercapacitors, electrocatalysis and other energy‐storage‐/‐conversion‐related fields.     

Solute re-encounter probabilities from dissociative oxciplex relaxation

Measurements of the quantum yield of self-sensitized 1,3-diphenylisobenzofuran peroxidation as a function of dissolved oxygen of added azulene concentrations indicate that oxygen quenching of the sensitizer singlet state produces both triplet and ground states of the sensitizer in addition to O₂(¹Δ_g) and O₂(³Σ^?_g). This partitioning of quenching products may be due to the competitive relaxation of the initially formed complex (oxciplex), or to sequential relaxation of different oxciplex states in which symmetry and spin barriers are negotiated by complex dissociation and re-encounter of the solute pair in the required configuration. The latter interpretation provides re-encounter probabilities for the processes M(T₁) + O₂(¹Δ_g) → M(T₁) + O₂(³Σ^?_g) and M(T₁) + O₂(³Σ^?_g) → M(S_o) + O₂(¹Δ_g) from which estimated rate constants are compatible with theoretical expectation.     

Enhancement of the Efficacy of Photodynamic Inactivation of Candida albicans with the Use of Biogenic Gold Nanoparticles

This study reports on successful photodynamic inactivation of planktonic and biofilm cells of Candida albicans using Rose Bengal (RB) in combination with biogenic gold nanoparticles synthesized by the cell‐free filtrate of Penicillium funiculosum BL1 strain. Monodispersed colloidal gold nanoparticles coated with proteins were characterized by a number of techniques including SEM–EDS, TEM, UV–Vis absorption and fluorescence spectroscopy, as well as Fourier transform infrared spectroscopy to be 24 ± 3 nm spheres. A Xe lamp (output power of 20mW, delivering intensity of 53 mW cm^?2) was used as a light source to study the effects of RB alone, the gold nanoparticles alone and the RB‐gold nanoparticle mixture on the viability of C. albicans cells. The most effective reduction in the number of planktonic cells was found after 30 min of Xe lamp light irradiation (95.4 J cm^?2) and was 4.89 log₁₀ that is 99.99% kill for the mixture of RB with gold nanoparticles compared with 2.19 log₁₀ or 99.37% for RB alone. The biofilm cells were more resistant to photodynamic inactivation, and the highest effective reduction in the number of cells was found after 30 min of irradiation in the presence of the RB–gold nanoparticles mixture and was 1.53 log₁₀, that is 97.04% kill compared with 0.6 log₁₀ or 74.73% for RB. The probable mechanism of enhancement of RB‐mediated photodynamic fungicidal efficacy against C. albicans in the presence of biogenic gold nanoparticles is discussed leading to the conclusion that this process may have a multifaceted character.     

The Properties and Activity of TiO2/beta‐SiC Nanocomposites in Organic Dyes Photodegradation

The TiO₂/beta‐SiC nanocomposites containing 0–25 wt. % of beta‐SiC were synthesized by the sol‐gel method and tested in the photodegradation of methylene blue and methyl orange water solutions. With the increase in SiC content, only a slight decrease in energy band gap was observed (3.19–3.12 eV), together with significant increase in the surface area of the catalysts (42.7–80.4 m² g^?1). In the synthesized material, the anatase phase of TiO₂ was present in the form of small agglomerates resulting from the mechanical mixing process. In the process conditions (catalyst concentration 0.5 g L^?1, initial dye concentration 100 ppm, light source 100 W UV‐Vis lamp), we have observed no signs of catalyst deactivation. The significantly higher photodegradation activity of methylene blue than methyl orange can be attributed to the preferable pH of the solution compared to pH_PZC and the cationic character of the first dye. In case of methyl orange, pH process conditions substantially limit the contact of the catalyst with the dye, as negatively charged surface of the catalysts repels the dissociated anionic dye molecules.     

The Effect of pH Values on the Synthesis,Microstructure and Photocatalytic Activity of Ce‐Bi2O3 by a Two‐Step Hydrothermal Method

In this study, the effect of pH values on the microstructure and photocatalytic activity of Ce‐Bi₂O₃ under visible light irradiation was investigated in detail. In alkaline condition (e.g. pH = 9), the as‐prepared Ce‐Bi₂O₃ exhibited an agglomerated status and mesoporous structures without a long‐range order. While in weak acid condition (e.g. pH = 5), the Ce‐Bi₂O₃ exhibited a best morphology with irregular nanosheets. Correspondingly, it possessed largest surface area (24.641 m² g^?1) and pore volume (9.825E‐02 cm³ g^?1). These unique nanosheets can offer an attachment for pollutant molecules and reduce the distance of electron immigration from inner to surface, thus facilitating the separation of photoelectron and hole pairs. Compared with the pure Bi₂O₃, the band gap of Ce‐Bi₂O₃ prepared at different pH was much lower. Among them, the band gap of Ce‐Bi₂O₃ (pH of 5) was lowest (2.61 eV). Ce‐Bi₂O₃ (pH of 5) exhibited as tetragonal crystal with the bismuth oxide in the form of the composites, which could reduce the band gap width or suppress the charge‐carrier recombination, subsequently possessing great photocatalytic activity for acid orange II under visible light irradiation. After 2 h degradation under visible light, the degradation rate of acid Orange II was up to 96.44% by Ce‐Bi₂O₃ prepared at pH 5. Overall, it can be concluded that the pH values had effects on the microstructure and photocatalytic activity of Ce‐Bi₂O₃ catalysts.     

Assessing the Applicability of Singlet Oxygen Photosensitizers in Leaf Studies

Singlet oxygen (¹O₂) is of special interest in plant stress physiology. Studies focused on internal, chlorophyll‐mediated production are often complemented with the use of artificial ¹O₂ photosensitizers. Here, we report a comparative study on the effects of Rose Bengal (RB), Methylene Violet (MVI), Neutral Red (NR) and Indigo Carmine (IC). These were infiltrated into tobacco leaves at concentrations generating the same fluxes of ¹O₂ in solution. Following green light‐induced ¹O₂ production from these dyes, leaf photosynthesis was characterized by Photosystem (PS) II and PSI electron transport and oxidative damage was monitored as degradation of D1, a PSII core protein. Cellular localizations were identified on the basis of the dyes’ fluorescence using confocal laser scanning microscopy. We found that RB and NR were both localized in chloroplasts but the latter had very little effect, probably due to its pH‐dependent photosensitizing. Both RB and intracellular, nonplastid MVI decreased PSII electron transport, but the effect of RB was stronger than that of MVI and only RB was capable of damaging the D1 protein. Intercellularly localized IC had no significant effect. Our results also suggest caution when using RB as photosensitizer because it affects PSII electron transport.     

Photodynamic Action Mechanism Mediated by Zinc(II) 2,9,16,23‐Tetrakis[4‐(N‐methylpyridyloxy)]phthalocyanine in Candida albicans Cells

The photoreaction type I/type II pathways mediated by zinc(II) 2,9,16,23‐tetrakis[4‐(N‐methylpyridyloxy)]phthalocyanine (ZnPPc⁴⁺) was studied in Candida albicans cells. This photosensitizer was strongly bound to C. albicans cells at short times. After 30 min irradiation, 5 μM ZnPPc⁴⁺ produced ~5 log decrease in cell viability. Different probes were used to detect reactive oxygen species (ROS) in cell suspensions (~10⁶ CFU mL^?1). Singlet molecular oxygen, O₂(¹Δ_g), was observed by the reaction with 9,10‐dimethylanthracene (DMA) and tetrasodium 2,2‐(anthracene‐9,10‐diyl)bis(methylmalonate) (ABMM), whereas the nitro blue tetrazolium (NBT) method was used to sense superoxide anion radical (). Moreover, the effects produced by an anoxic atmosphere and cell suspensions in D₂O, as well as the addition of sodium azide and mannitol as ROS trapping were evaluated in the PDI of C. albicans. These investigation indicates that O₂(¹Δ_g) is generated in the cells, although a minor extension other radical species can also be involved in the PDI of C. albicans mediated by ZnPPc⁴⁺.     

One‐Step Pyro‐Synthesis of a Nanostructured Mn3O4/C Electrode with Long Cycle Stability for Rechargeable Lithium‐Ion Batteries

A nanostructured Mn₃O₄/C electrode was prepared by a one‐step polyol‐assisted pyro‐synthesis without any post‐heat treatments. The as‐prepared Mn₃O₄/C revealed nanostructured morphology comprised of secondary aggregates formed from carbon‐coated primary particles of average diameters ranging between 20 and 40 nm, as evidenced from the electron microscopy studies. The N₂ adsorption studies reveal a hierarchical porous feature in the nanostructured electrode. The nanostructured morphology appears to be related to the present rapid combustion strategy. The nanostructured porous Mn₃O₄/C electrode demonstrated impressive electrode properties with reversible capacities of 666 mAh g^?1 at a current density of 33 mA g^?1, good capacity retentions (1141 mAh g^?1 with 100 % Coulombic efficiencies at the 100^th cycle), and rate capabilities (307 and 202 mAh g^?1 at 528 and 1056 mA g^?1, respectively) when tested as an anode for lithium‐ion battery applications.     

A ferrocene‐containing porous organic polymer linked by tetrahedral silicon‐centered units for gas sorption

A novel ferrocene‐containing porous organic polymer (FPOP) has been prepared by Sonogashira‐Hagihara coupling reaction of 1,1′‐dibromoferrocene and tetrakis(4‐ethynylphenyl)silane. Compared with other polymers, the resulting polymer possesses excellent thermal stability with the decomposition temperature of 415°C and high porosity with Brunauer–Emmett–Teller (BET) surface area of 542 m² g^?1 as measured by nitrogen adsorption‐desoprtion isotherm at 77 K. For applications, it shows moderate carbon dioxide uptakes of up to 1.42 mmol g^?1 (6.26 wt%) at 273 K/1.0 bar and 0.82 mmol g^?1 (3.62 wt%) at 298 K/1.0 bar, and hydrogen capacity of up to 0.45 mmol g^?1 (0.91 wt%) at 77 K/1.0 bar, indicating that FPOP might be utilized as a promising candidate for storing carbon dioxide and hydrogen. Although FPOP possesses lower porosity than many porous polymers, the gas capacities are higher or comparable to them, thereby revealing that the incorporation of ferrocene units into the network is an effective strategy to enhance the affinity between the framework and gas.     

Anchoring H3PW12O40 on aminopropylsilanized spinel‐type cobalt oxide (Co3O4‐SiPrNH2/H3PW12O40): A novel nanohybrid adsorbent for removing cationic organic dye pollutants from aqueous solutions

In this work, phosphotungstic acid (H₃PW₁₂O₄₀; PW₁₂) was chemically anchored on aminopropylsiloxane functionalized spherical Co₃O₄ nanoparticles (Co₃O₄–SiPrNH₂) and the resultant nanocomposite (Co₃O₄–SiPrNH₂/PW₁₂) was fully characterized. The results demonstrated successful anchoring of PW₁₂ on the surface of Co₃O₄–SiPrNH₂nanoparticles. The Co₃O₄–SiPrNH₂/PW₁₂ nanohybrid indicated a specific surface area of 42.14 m² g^?1, which was greater than that of pure PW₁₂ (ca. 5 m² g^?1). The adsorption efficiency of this novel adsorbent nanomaterial was evaluated for removing methylene blue (MB), rhodamine B (RhB) and methyl orange (MO) dyes from aqueous solutions. The hybrid nanomaterial exhibited a high adsorption rate and selective adsorptivity for the cationic MB and RhB dyes compared to those for anionic MO dye. The prepared hybrid nanomaterial removed over 98% of MB within 12 min. The effects of initial pH, contact time, adsorbent dosage, and temperature were investigated on the adsorption process. The adsorption capacity of nanohybrid for cationic MB dye was 38.46 mg g^‐1. Also, adsorption kinetics indicated that the adsorption by Co₃O₄–SiPrNH₂/PW₁₂ was well‐modeled using pseudo‐second‐order kinetic model. Finally, thermodynamic parameters revealed that the adsorption was endothermic and spontaneous. The adsorption rate and ability of the Co₃O₄–SiPrNH₂/PW₁₂ were enhanced as compared with Co₃O₄ and Co₃O₄–SiPrNH₂ samples due to enhanced electrostatic attraction intraction. The nanohybride was easily separated and reused without any change in structure. Thus, it could be a promising green adsorbent for removing organic pollutants in water.     

Synthesis of noble‐metal‐free ternary K7HNb6O19/Cd0.5Zn0.5S/g‐C3N4 tandem heterojunctions for efficient photocatalytic performance under visible light

Exploring noble‐metal‐free, highly active and durable catalysts is vital to get to grips with the energy and environmental issues. Herein, we first dexterously design and synthesize a class of ternary Nb₆/CZS/g‐CN photocatalysts for the removal of hexavalent chromium Cr (VI) and organic dye pollutant (MO) from wastewater under visible‐light irradiation. A heterojunction Nb₆–1/CZS/g‐CN loaded with 0.01 g K₇HNb₆O₁₉ showed excellent photocatalytic performance, with the MO photodegradation efficiency of 94% in 1 h and the Cr (VI) (150 mg/l) photoreduction efficiency as high as 91% in 2 hr. The main active species were deemed to be O₂^.‐. Additionally, the as‐prepared ternary heterojunction exhibits superior hydrogen evolution reaction (HER) rate. A heterojunction Nb₆–4/CZS/g‐CN loaded with 0.5 g K₇HNb₆O₁₉ exhibited the highest H₂ evolution rate as high as 1777.86 μmol h^?1 g^?1 under visible‐light illumination, which is increased to 5.7 and 2.7 times that of bare CZS and biphase heterojunction CZS/g‐CN_. These findings afford a new class of promising low‐cost photocatalyst bodying for its huge potential value in sustainable energy development and wastewater treatment.     

One‐Pot Synthesis of Pomegranate‐Structured Fe3O4/Carbon Nanospheres‐Doped Graphene Aerogel for High‐Rate Lithium Ion Batteries

A unique hierarchically nanostructured composite of iron oxide/carbon (Fe₃O₄/C) nanospheres‐doped three‐dimensional (3D) graphene aerogel has been fabricated by a one‐pot hydrothermal strategy. In this novel nanostructured composite aerogel, uniform Fe₃O₄ nanocrystals (5–10 nm) are individually embedded in carbon nanospheres (ca. 50 nm) forming a pomegranate‐like structure. The carbon matrix suppresses the aggregation of Fe₃O₄ nanocrystals, avoids direct exposure of the encapsulated Fe₃O₄ to the electrolyte, and buffers the volume expansion. Meanwhile, the interconnected 3D graphene aerogel further serves to reinforce the structure of the Fe₃O₄/C nanospheres and enhances the electrical conductivity of the overall electrode. Therefore, the carbon matrix and the interconnected graphene network entrap the Fe₃O₄ nanocrystals such that their electrochemical function is retained even after fracture. This novel hierarchical aerogel structure delivers a long‐term stability of 634 mA h g^?1 over 1000 cycles at a high current density of 6 A g^?1 (7 C), and an excellent rate capability of 413 mA h g^?1 at 10 A g^?1 (11 C), thus exhibiting great potential as an anode composite structure for durable high‐rate lithium‐ion batteries.     

Photo‐Fenton and Riboflavin‐photosensitized Processes of the Isoxaflutole Herbicide

The proherbicide Isoxaflutole (IXF) hydrolyzes spontaneously to diketonitrile (DKN) a phytotoxic compound with herbicidal activity. In this work, the sensitized degradation of IXF using Riboflavin (Rf), a typical environmentally friendly sensitizer, Fenton and photo‐Fenton processes has been studied. The results indicate that only the photo‐Fenton process produces a significant degradation of the IXF. Photolysis experiments of IXF sensitized by Riboflavin is not a meaningful process, IXF quenches the Rf excited triplet (³Rf*) state with a quenching rate constant of 1.5 · 10⁷ m ^?1 s^?1 and no reaction is observed with the species O₂(¹Δ_g) or ${\mathrm{O}}_2^{·?}$ generated from ³Rf*. The Fenton reaction produces no changes in the IXF concentration. While the photo‐Fenton process of the IXF, under typical conditions, it produces a degradation of 99% and a mineralization to CO₂ and H₂O of 88%. A rate constant value of 1.0 × 10⁹ m ^?1 s^?1 was determined for the reaction between IXF and HO˙. The photo‐Fenton process degradation products were identified by UHPLC‐MS/MS analysis.     

Octa[4‐(9‐carbazolyl)phenyl]silsesquioxane‐Based Porous Material for Dyes Adsorption and Sensing of Nitroaromatic Compounds

A new fluorescent hybrid porous polymer (HPP) is synthesized by an anhydrous FeCl₃‐mediated oxidative coupling reaction of octa[4‐(9‐carbazolyl)phenyl]silsesquioxane (OCPS). The polymer possesses a surface area of 1741 m² g^?1 and hierarchical bimodal micropores (1.41 and 1.69 nm) and mesopores (2.65 nm). The material serves as an excellent adsorbent for CO₂ and dyes with high adsorption capacity for CO₂ (8.53 wt %,1.94 mmol g^?1), congo red (1715 mg g^?1) and rhodamine B (1501 mg g^?1). In addition, the presence of peripheral cabozolyl groups with extended π‐conjugation in the crosslinked framework imparts luminescent character to the polymer and offers the detection of nitroaromatic compounds.     

Self‐Assembling Synthesis of Free‐standing Nanoporous Graphene–Transition‐Metal Oxide Flexible Electrodes for High‐Performance Lithium‐Ion Batteries and Supercapacitors

The synthesis of nanoporous graphene by a convenient carbon nanofiber assisted self‐assembly approach is reported. Porous structures with large pore volumes, high surface areas, and well‐controlled pore sizes were achieved by employing spherical silica as hard templates with different diameters. Through a general wet‐immersion method, transition‐metal oxide (Fe₃O₄, Co₃O₄, NiO) nanocrystals can be easily loaded into nanoporous graphene papers to form three‐dimensional flexible nanoarchitectures. When directly applied as electrodes in lithium‐ion batteries and supercapacitors, the materials exhibited superior electrochemical performances, including an ultra‐high specific capacity, an extended long cycle life, and a high rate capability. In particular, nanoporous Fe₃O₄–graphene composites can deliver a reversible specific capacity of 1427.5 mAh g^?1 at a high current density of 1000 mA g^?1 as anode materials in lithium‐ion batteries. Furthermore, nanoporous Co₃O₄–graphene composites achieved a high supercapacitance of 424.2 F g^?1. This work demonstrated that the as‐developed freestanding nanoporous graphene papers could have significant potential for energy storage and conversion applications.     

Photoinduced Degradation of the Herbicide Clomazone Model Reactions for Natural and Technical Systems

The photodegradation of the herbicide clomazone in the presence of S₂O₈^2? or of humic substances of different origin was investigated. A value of (9.4 ± 0.4) × 10⁸ m ^?1 s^?1 was measured for the bimolecular rate constant for the reaction of sulfate radicals with clomazone in flash‐photolysis experiments. Steady state photolysis of peroxydisulfate, leading to the formation of the sulfate radicals, in the presence of clomazone was shown to be an efficient photodegradation method of the herbicide. This is a relevant result regarding the in situ chemical oxidation procedures involving peroxydisulfate as the oxidant. The main reaction products are 2‐chlorobenzylalcohol and 2‐chlorobenzaldehyde. The degradation kinetics of clomazone was also studied under steady state conditions induced by photolysis of Aldrich humic acid or a vermicompost extract (VCE). The results indicate that singlet oxygen is the main species responsible for clomazone degradation. The quantum yield of O₂(a¹Δ_g) generation (λ = 400 nm) for the VCE in D₂O, Φ_Δ = (1.3 ± 0.1) × 10^?3, was determined by measuring the O₂(a¹Δ_g) phosphorescence at 1270 nm. The value of the overall quenching constant of O₂(a¹Δ_g) by clomazone was found to be (5.7 ± 0.3) × 10⁷ m ^?1 s^?1 in D₂O. The bimolecular rate constant for the reaction of clomazone with singlet oxygen was k_r = (5.4 ± 0.1) × 10⁷ m ^?1 s^?1, which means that the quenching process is mainly reactive.