Visible Light Irradiation In Presence Research Articles

A General Copper-Box System for the Asymmetric Arylative Functionalization of Benzylic, Propargylic or Allenylic Radicals.

Radical-involved arylative cross-coupling reactions have recently emerged as an attractive strategy to access valuable aryl-substituted motifs. However, there still exist several challenges such as limited scope of radical precursors/acceptors, and lack of general asymmetric catalytic systems, especially regarding the multicomponent variants. Herein, we reported a general copper-Box system for asymmetric three-component arylative radical cross-coupling of vinylarenes and 1,3-enynes, with oxime carbonates and aryl boronic acids. The reactions proceed under practical conditions in the absence or presence of visible-light irradiation, affording chiral 1,1-diarylalkanes, benzylic alkynes and allenes with good enantioselectivities. Mechanistic studies imply that the copper/Box complexes play a dual role in both radical generation and ensuing asymmetric cross-coupling. In the cases of 1,3-enynes, visible-light irradiation could improve the activity of copper/Box complex toward the initial radical generation, enabling better efficiency match between radical formation and cross-coupling.

“Efficacy of datura metel leaf extract on MnSrO2 NPs synthesized using a green method in terms of pollutant reduction and antimicrobial activity.”

In this work, we prepared both chemical and biogenic synthesis of MnSrO2 (0, 5, 20 ml DLE) nanoparticles using datura metel leaf extraction by co-precipitation method and also prepared Sulfadiazine dye for catalytic activity. The applications and properties of green MnSrO2 nanoparticles have compared and they were characterized via XRD, SEM, FT-IR, EDX, UV–visible, and PL techniques. These nanoparticles showed an 18–8 nm diameter range, which was arranged in a spherical form combined randomly. The evidence from FTIR spectra showed peaks around 492, 487, 483, 655, 606, and 603 cm−1 for the creation of SrMnO2 NPs. Antibacterial activity of MnSrO2 (0, 5, 20 ml DLE) was measured by the well-diffusion method against pathogens, Staphylococcus aureus and Klebsiella pneumonia. The photocatalytic activity of the synthesized metal oxide nanoparticles was investigated by UV–visible spectroscopy for Sulfadiazine dye degradation with bare MnSrO2 NPs, g-MnSrO2 NPs [5 ml DLE], and g-MnSrO2 NPs [20 ml DLE] in presence of visible light irradiation.

Mn-MOF derived N-doped MnOx@carbon heterogeneous catalysts for Vis-light, S2O82[sbnd], HSO5[sbnd], Vis/S2O82[sbnd], and Vis/HSO5[sbnd]-induced degradation of metronidazole: Kinetics and mechanistic study

Manganese oxide-based nanostructures have demonstrated remarkable potential for reactive radical generation to treat wastewater by activating persulfate (PS) and peroxymonosulfate (PMS) in the presence of visible-light irradiation. Herein, we report a facile strategy to synthesize nitrogen-doped porous MnOx@Carbon nanostructures by annealing Mn-based MOF at different temperatures and employed for the degradation of MTZ under Vis-light, PS, PMS, Vis/PS, and Vis/PMS systems. A significant catalytic synergy was found in the MnO-I/Vis/PMS system. Owing to the rational coordination of nitrogen-enriched porous manganese oxide embedded carbon, high surface area (179.6 m2/g), and surface-exposed abundant active sites, the composite named MnO-I exhibited excellent catalytic performance in all the studied processes. The carbonization process induces a polarization difference between Mn-N co-ordination, resulting in the carbon becoming an electron-deficient core and manganese an electron-rich center, thus providing more Mn (II/III) for PMS activation. The degradation study showed that 99 % removal of MTZ was achieved within 40 min, with a rate constant of 0.099 min−1, in the MnO-I/Vis/PMS system. Trapping experiments and EPR detection demonstrated that SO4•−, OH• and 1O2 radicals were the major species involved in the degradation process. Besides, the degradation pathway and impact of operational parameters, i.e., catalyst dosage, PMS concentration, initial pH, MTZ concentration, co-existing anions, and humic acid, on the removal of MTZ were also explored.

Chlorin Conjugates in Photodynamic Chemotherapy for Triple-Negative Breast Cancer.

Breast cancer (BC) is the most common type of cancer in women and the number of new cases in the US is still increasing each year. Triple-negative breast cancer (TNBC), which comprises 15-20% of all breast cancer, is a heterogeneous disease and is considered the most aggressive type of breast cancer due to the lack of estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2) expressions for treatments. Traditional chemotherapy is the standard protocol for the treatment of TNBC. Toxicity and multidrug resistance are major drawbacks to chemotherapy. The lack of molecular targets and poor prognosis for TNBC prompts an urgent need to discover novel therapeutic strategies to improve clinical outcomes and quality of life for patients. Photodynamic therapy (PDT) or light treatment is a binary anti-cancer procedure that uses a photosensitizer (PS) that, upon light activation, produces cytotoxic oxygen species, destroying tumor cells. PDT is minimally invasive and can be repeated a few times without accumulating significant toxicity in the surrounding tissues. The primary goal of this study was to investigate in vitro photodynamic chemotherapy as a ternary combination therapy using our synthesized photosensitizers (chlorin-vitamin conjugates and their corresponding indium complexes) co-treated with known chemotherapeutic agents (taxol, doxorubicin, cisplatin, fluorouracil, or methotrexate) in the presence of light and determine the optimum conditions as a pre-clinical study of an enhanced tumoricidal effect against TNBC. Our results indicated that the best combination for an effective chemophotodynamic effect involves a ternary treatment of the indium complex of the chlorin-lipoic acid conjugate (InCLA) co-treated with taxol, which exhibited strong synergism at the nanomolar concentration when combined in the presence of visible light irradiation. Other ternary combinations containing taxol with a synergistic anti-tumor effect against TNBC include chlorin-pantothenic acid (CPA) and chlorin-biotin (CBTN) conjugates. Several other ternary combinations containing InCLA, CBTN, and CPA with either cisplatin, fluorouracil, or methotrexate were identified to generate a synergistic or additive effect. The light dosage remained constant, but the dosages of photosensitizers and chemotherapy drugs were varied to obtain the lowest possible concentration for the desired effect. The synergistic, additive or antagonistic effects of the drug combinations were determined based on the Chou-Talalay method, with InCLA-taxol having the lowest combination index (CI) of 0.25. Fluorescence and transmission electron microscopy (TEM) images provided evidence of apoptosis as the preferred mode of cell death. Our study demonstrated the combination of PDT and chemotherapy as a potential treatment option for TNBC patients.

Novel Fe-MOF@Cu/NiAl-LDH as Photo-Catalysts in Methane Bireforming: Effect of Preparation Strategy

AbstractIn this work, Fe-MOF@Ni/CuAl-LDH nanocomposites are developed for the first time in photocatalytic CO2/CH4 conversion to ultrapure formaldehyde. The reaction takes place in a dynamic (continuous flow) photosystem working under atmospheric pressure in presence of visible-light irradiation. The visible-light-active photocatalysts are prepared using two strategies in order to enhance both morphology and optical properties of the new composite. First strategy based on growing of MOF on the in-situ N2 exfoliated LDH using solvothermal reaction (FMNHT and FMCHT), where, the MOF is formed on surface and/or inside lamellar layer. The second based on formation of LDH around the previously prepared Fe-MOF via microwave assisted method (NFMMW and CFMMW). The data herein indicate that, both samples NFMMW and CFMMW, have LDH/MOF strong electronic coupling and exhibit an adjustable band gap share in improve charge generation/separation rate, reduce e−/h+ recombination rate and increase light absorption capacity. Those characteristics provide higher efficiency in photocatalytic CH4/CO2 conversion and give high selectivity toward ultrapure formaldehyde formation (99.9%).

Regioselective Hydro(deutero)silylation of 1,3-Enynes Enabled by Photoredox/Nickel Dual Catalysis.

In the presence of visible light irradiation, organophoto/nickel dual catalysts, and the mild base K2HPO4, 1,3-enynes react with silanecarboxylic acids to give the corresponding α-silylallenes with high selectivity. In this uniquely decarboxylative hydrosilylation of 1,3-enynes, a silyl radical process is involved and diverse electron-rich and -poor substrates proceed smoothly in moderate to excellent yields. This transformation is particularly synthetically worthwhile when using MeOD as the solvent, which furnishes new access to α-silyldeuteroallenes.

Effect of Lanthanum Loading on the Photocatalytic Degradation of Brilliant Yellow and Acid Blue Dyes in Visible Light and Sunlight over La2O3-TiO2 Nanocomposites

La-doped TiO2 nanocomposites were synthesized using the sol-gel process with different proportions of lanthanum doping (1-5 wt.%). The synthesized nanocomposites were analyzed thoroughly by X-ray diffraction (XRD), nitrogen adsorption, scanning electron microscopy (SEM) with extended X-ray diffraction (EDAX), transmission electron microscopy, ultraviolet-visible DRS spectra for optical properties, photoluminescence (PL) for emission behaviours, Fourier transform infrared (FTIR) spectroscopy (FTIR) for chemical bonding analysis and X-ray photoelectron spectroscopy (XPS) for surface chemical composition. The XRD analysis confirmed the anatase phase for all synthesized La-TiO2 nanocomposites. The UV-Vis spectra showed an increased absorption in the visible range and a slight red shift of binding energy as the % La doping increased from 1-5 wt.%. Similarly, the binding energy values varied from 3.02 to 2.75 eV with increased La doping. These nanocomposites exhibited the photocatalytic activity achieving 99% degradation of acid blue dye and 96% degradation of brilliant yellow dye in the presence of visible light irradiation. Scavenger studies indicated that the dye degradation was suppressed, suggesting the involvement of superoxide (O2–), hydroxyl radical (OH•) and holes (h+) in the reaction mechanism.

Unified Approach to Diverse Heterocyclic Synthesis: Organo-Photocatalyzed Carboacylation of Alkenes and Alkynes from Feedstock Aldehydes and Alcohols.

We report an organo-photocatalyzed carboacylation reaction that offers a springboard to create chemical complexity in a diversity-driven approach. The modular one-pot method uses feedstock aldehydes and alcohols as acyl surrogates and commercially available Eosin Y as the photoredox catalyst, making it simple and affordable to introduce structural diversity. Several biologically relevant skeletons have been easily synthesized under mild conditions in the presence of visible light irradiation by fostering a radical acylation/cyclization cascade. The proposed reaction mechanism was further illuminated by a number of spectroscopic studies. Furthermore, we applied this protocol for the late-stage functionalization of pharmaceuticals and blockbuster drugs.

An Efficient Intercalation Supramolecular Structure for Photocatalytic CO2 Reduction to Ethylene Under Visible Light

AbstractPhotocatalytic CO2 reduction (CO2PR) into multi‐carbon products (especially C2H4) is a highly attractive route for global carbon cycle, however, which is seriously limited by sluggish C‐C coupling kinetics and competitive hydrogen evolution reaction (HER) and so on. Herein, the fabrication of a novel supramolecular assembly of NiAl‐Fe‐TCPP is reported by intercalating iron porphyrin (Fe‐TCPP) into NiAl‐layered double hydroxide (NiAl‐LDH), and the resultant NiAl‐Fe‐TCPP exhibit superior catalytic performance on CO2PR to C2H4 under visible light irradiation in presence of photosensitizer. A high C2H4 selectivity up to 93.4% in the carbon‐containing products with the production rate as high as 24.7 µmol h−1 can be achieved over NiAl‐Fe‐TCPP. The ex/in situ X–ray absorption spectoscopy (XAS) indicates that the electron transfer between NiAl‐LDH and Fe‐TCPP can promote the generation of low‐valence of Fe sites, resulting in the efficient production of C2H4. The spin‐polarized density functional theory (DFT) calculations find that the synergistic mechanism that CO2 molecules are activated to CO on NiAl‐LDH and then spilled to Fe‐TCPP and coupled to COCHO#, which is further reduced to C2H4, are feasible in the perspective of Gibbs free energy. Moreover, the strong host‐guest interactions between NiAl‐LDH and Fe‐TCPP lead to the promoted photocatalytic activity and superior cycle stability.

Novel morphological mono-metallic substituted polyoxometalate immobilized 3-(aminopropyl)-imidazole photocatalysts for visible-light driven degradation: Anti-bacterial activity, membrane bacterial activity applications

A novel keggin-type tetra-metalates substituted polyoxometalate was functionalized by 3-(aminopropyl)-imidazole (3-API) supporting a ligand substitution method. In this paper, polyoxometalate (POMs) (NH4)3 [PMo12O40] and transition metal substituted of (NH4)3 [{PMIVMo11O40}.(H2O)] (M = Mn, V) are used as one of the adsorbents. The 3-API/POMs hybrid have been synthesized and used as adsorbent for the photo-catalysis of azo-dye molecule degradation after visible-light illumination as a simulated organic contaminant in water. The transition metal (M = MIV, VIV) substituted keggin-type anions (MPOMs) were synthesized, which reveals the degradation of methyl orange (MO) of about 94.0 % and 88.6 %. Immobilizing high redox ability POMs as an efficient acceptor of photo generated electron, on metal 3-API. In the presence of visible light irradiation result reveals that 3-API/POMs (89.9 %) have incredibly achieved after certain irradiation time and at specific conditions (3)-API/POMs; photo-catalysts dose = 5mg/100 ml, pH = 3 and MO dye concentration = 5 ppm). As the surface of POM catalyst has strong absorption of azo-dye MO molecule engaged as a molecular exploration through photo catalytic reactant. From the SEM images it is clear that the synthesized POMs based materials and POMs conjugated MO have varieties of morphological changes observed such as flakes, rods and spherical like structures. Anti-bacterial study reveals that the process of targeted microorganism occur higher activity against pathogenic bacterium for 180 min of visible-light irradiation is measured in terms of zone of the inhibition. Furthermore, the photo catalytic degradation mechanism of MO using POM, metaled POMs and 3-API/POMs also has been discussed.

Photocatalytic Disulfide Bond Coupling by Surface-Reduced Manganese Oxide for Controlled Polysulfide-Based Polymer Synthesis

Manganese oxide (MnO2) is a commonly used vulcanizing agent, which can convert polysulfide oligomers with reactive terminal mercaptans into polymeric networks. Herein, an elegant approach for the fast and facile curing behavior of polysulfide rubbers was disclosed under visible-light irradiation. Photocatalytic disulfide bond coupling of mercaptan end groups can be achieved on MnO2 in the presence of visible-light irradiation. More importantly, compared with pristine MnO2, surface-reduced MnO2 (R-MnO2) with abundant Mn3+ sites and oxygen vacancies exhibited superior vulcanizing performance. Theoretical simulation uncovers that R-MnO2 can facilitate electron transfer due to a narrowed energy band gap and reduce the energy barriers required for photocatalytic disulfide bond formation. This work opens up the potential of using visible light together with surface modification to tune the vulcanizing process and the properties of polysulfide rubbers.

Rational design of Mg2Sn2O4/rGO/Ag nanocomposites with enhanced photocatalytic and antibacterial activities

A Mg2Sn2O4, Mg2Sn2O4/rGO and Mg2Sn2O4/rGO/Ag nanocomposites encompass a new brand of the nanocatalyst, which can be broad-minded to a professional photocatalyst via visible light because of this attractive photocatalytic activity by UV Visible spectroscopy. In particular, Mg2Sn2O4 nanoparticles enclose low bandgap energy consequently enhancing photocatalytic dye degradation. Herewith, these Mg2Sn2O4, Mg2Sn2O4/rGO and Mg2Sn2O4/rGO/Ag nanocomposites were prepared by a hydrothermal method. The Mg2Sn2O4, Mg2Sn2O4/rGO and Mg2Sn2O4/rGO/Ag nanocomposites were tested towards FT-IR, XRD, Raman, DRS UV–Visible spectroscopy and Scanning electron microscopy (SEM) analysis. In FT-IR spectroscopy investigations, Peaks 423 and 548 cm−1 is confirmed to the Mg–O–Mg (M-O-M) and O–Sn–O (O-M-O) groups. The 485, 658, and 750 cm−1 is can be assigned to the Sn–O modes and peaks 578 and 917 cm−1 is corresponds to Mg–O bonds, which was carried out by Raman spectroscopy analysis. The Mg2Sn2O4 nanoparticle's cubic phase of the crystal system was confirmed by XRD studies. Pure Mg2Sn2O4 nanoparticle's observed band gap energies values at 2.7eV. The crystal shape and sheets like morphology were determined by SEM analysis. Mg2Sn2O4, Mg2Sn2O4/rGO and Mg2Sn2O4/rGO/Ag nanocomposites were evaluated by photocatalytic activities under visible light irradiation in presence of Malachite Green dye (MG). Hence, Mg2Sn2O4/rGO/Ag nanocomposites have higher degradation efficiency when compare to the Mg2Sn2O4, Mg2Sn2O4/rGO nanocomposites. Moreover, the Mg2Sn2O4/rGO/Ag nanocomposites was tested to the antibacterial activity with Gram-positive Staphylococcus aureus (S. Aureus) and Gram-negative Salmonella Typhi (S. Typhi) bacteria. Finally, as proposed materials are enhanced to the antibacterial and photocatalytic activities.

ZnO−Ag Hybrid Nanoparticles Used in the Antimicrobial Solvent‐Based Coatings: Antibacterial Studies in the Darkness and Under Visible‐Light Irradiation

AbstractThis study explores how hybrid nanoparticles can be used to improve the antibacteial properties of both single nanoparticles and their polymeric nanocomposite coatings. Hybridization of two different nanoparicles, such as nano‐ZnO and silver nanoparticles (AgNPs) has been carried out to combine advantages of the individual particles. For these purposes, firstly ZnO−Ag hybrid nanoparticles were chemically fabricated by reducing Ag+ precursor on the as‐received nano‐ZnO using sodium borohydride in aqueous medium. Thereafter, these ZnO−Ag nanohybrids were introduced into the acrylic polyurethane matrix (at 2 wt.%) under sonication in xylene/toluene solvents. To reveal the effect of hybridization on the antibacterial activity against E. coli of both ZnO−Ag nanohybrids and their nanocomposite coatings, two antibacterial tests have been carrieried out in presence of visible light irradiation or without light (in dark). The agar‐well diffusion method indicated that ZnO−Ag nanohybrids exhibited high antibacterial activity against E.coli at the low concentration (8 mg/mL). In addition, their larger inhibition zones under visible light exposure were observed, when compared to the dark condition. Similarity, antibacterial test (ISO 22196 : 2007 standard) indicated that nanocomposite coating under visible light exposure had a higher antibacterial activity than that in the dark condition. Data from this antibacterial test after 24 h indicated that the visible light exposure provided more bactericidal efficiency for APU/ZnO−Ag coating (4.17 log), as compared to the dark condition (4.07 log). This increase in the bactericidal efficiency can be attributed to the hybridization of nano‐ZnO and AgNPs in their hybrid nanostructure. From the experimental data, we propose the mechanism for antibacterial activity of ZnO−Ag hybrid nanoparticles. In addition, TEM photographs indicated that AgNPs (10–30 nm) were attached to the surface of nano‐ZnO (<100 nm). Data from the diffused reflectance spectra indicated that the deposition of AgNPs on nano‐ZnO reduced its band gap energy (Eg) from 3.2 eV to 2.75 eV. In case of nanocomposite coating, addition of 2 wt.% ZnO−Ag nanohybrids into the acrylic polyurethane matrix significantly increased their impact strength and abrasion resistance.

Cover Feature: Fe3O4/g‐C3N4 Nanozyme for Production of L‐DOPA as Mimetics of Tyrosine Hydroxylase (ChemNanoMat 2/2023)

A nanozyme was developed for biomimetic synthesis of L-DOPA by mimicking natural tyrosine hydroxylase. Fe3O4/g-C3N4 nanocomposite performed as a nanozyme with close resemblance in structure, activity, and mechanism to tyrosine hydroxylase. Fe atoms coordinated with N atom in g-C3N4 nanosheet served as the active site of the nanozyme. The nanozyme catalyzed selective hydroxylation of tyrosine to L-DOPA in the presence of visible light irradiation and hydrogen peroxide. The nanozyme shared an identical catalytic mechanism with tyrosine hydroxylase from the aspect of involvement of FeIVO2+. More information can be found in the Research Article by Wenbin Liu et al.

A Z-scheme BiYO3/g-C3N4 heterojunction photocatalyst for the degradation of organic pollutants under visible light irradiation.

Photocatalysis is one of the fascinating fields for the wastewater treatment. In this regard, the present study deals with an effective visible light active BiYO3/g-C3N4 heterojunction nanocomposite photocatalyst with various ratios of BiYO3 and g-C3N4 (1:3, 1:1 and 3:1), synthesised by a wet chemical approach. The as-synthesised nanocomposite photocatalysts were investigated via different physicochemical approaches like Fourier transform infrared (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), transmission electrons microscopy (TEM), UV-vis diffuse reflectance spectroscopy (DRS), photoluminescence (PL) and photoelectrochemical studies to characterise the crystal structure, morphology, optical absorption characteristics and photoelectrochemical properties. The photocatalytic degradation ability of the prepared photocatalytic samples was also analysed through the degradation of RhB in the presence of visible light irradiation. Of all the synthesised photocatalysts, the optimised CB-1 composite showed a significant photocatalytic efficiency (88.7%), with excellent stability and recyclability after three cycles. O2•- and •OH radicals were found to act a major role in the RhB degradation using optimised CB-1 composite, and it possessed ~ 1 times greater photocurrent intensity than the pristine g-C3N4 and BiYO3. In the present work, a direct Z-scheme heterojunction BiYO3/g-C3N4 with a considerably improved photocatalytic performance is reported.

Improved catalytic efficiency by N-doped TiO2 via sol gel under microwave irradiation: Dual applications in degradation of dye and microbes

The present research is to develop a facile and a fast microwave irradiation method to synthesise uniform and well-defined nitrogen-doped TiO2 nanocatalysts through the microwave-assisted sol-gel method. Advanced spectroscopic and analytical techniques are to be used to investigate the characteristics of the prepared catalyst samples. The synthesised nanocatalyst's XRD analysis shows lattice fringes for anatase phases. The XPS reveals the electronic state and composition of the dopant, which is almost consistent with the practically added concentration of dopant. The spectral shift (red shift) to the visible light region was demonstrated by the UV-visible diffuse reflectance spectroscopy analysis. The results demonstrated that NT3M4 has a reduced band gap of 2.56 ​eV. The HRTEM images of the NT3M4 analysis illustrate nanoparticles of spherical shape with a particle size of 6.3 ​nm. The surface properties and elemental composition were studied by SEM analysis, which depicts the irregular and rough morphology of the nanocatalysts. According to the Brunauer-Emmett-Teller (BET) results, NT3M4has a large surface area of 103 m2/g1. Type IV isotherms indicate the presence of the mesoporous structure in the nitrogen adsorption-desorption isotherm. The synthesised nanocatalyst NT3M4 demonstrated the best photocatalytic ability under visible light, which enhanced the rate of degradation of indigo carmine dye within 70 ​min. NT3M4 also exhibits antibacterial and antifungal activity. Further, this catalyst shows almost equal activity with standard chloramphenicol. Thus, the current study suggests microwave-assisted sol-gel methods for fabricating N-TiO2 nanocatalysts with the best photocatalytic performance for the degradation of harmful organic pollutants and pathogens in the presence of visible light irradiation.

Synthesis and characterization of SbSI modified g-C3N4 composite for photocatalytic and energy storage applications

Two dimensional carbon related materials with superior charge separation and excellent transport properties have been highly used in the field of photocatalytic and electrochemical applications. The hydrothermally synthesized antimony sulfoiodide (SbSI) doped g-C3N4 composite (CSI) has excellent charge storage and charge transport properties. The physio-chemical properties of the synthesized SbSI doped g-C3N4 materials are examined by X-ray diffraction (XRD), transmission electron microscopy (TEM) energy dispersive x-ray spectroscopy (EDS), Fourier transform-infra red spectroscopy (FT-IR), Ultraviolet-diffuse reflectance spectroscopy (UV-DRS), X-ray photoelectron spectroscopy (XPS) and photoluminescence spectroscopy (PL) techniques. The photocatalytic examination of the synthesized catalyst materials is carried out in presence of visible light irradiation using Rhodamine B (RhB), Bromophenol blue (BPB) and mixed dye effluents. The synthesized photocatalyst material CSI shows excellent photocatalytic activity of 94%, 80% and 92% against BPB, RhB and mixed dye effluent and the stability of the prepared material was 95% even after four consecutive photocatalytic performances. In addition, the electrochemical properties of the synthesized CSI composite is examined by cyclic voltammetry (CV), galvanostatic charge-discharge (GCD) analysis and electrochemical impedance spectroscopy (EIS) investigations. The synthesized composite material depicts good specific capacitance of 212 F/g at 0.5 A/g current density and retains 96% of the stability after 1000 consecutive GCD performance. The experimental finding confirms that the CSI composites have enhanced photocatalytic and electrochemical performance than the synthesized SbSI and g-C3N4 materials.

Fe3O4/g‐C3N4 Nanozyme for Production of L‐DOPA as Mimetics of Tyrosine Hydroxylase

AbstractL‐DOPA is in large demand as the mainstay of therapeutic treatment for Parkinson's disease. The development of a facile route is urgently required for production of L‐DOPA. A nanozyme was developed for biomimetic synthesis of L‐DOPA by mimicking natural tyrosine hydroxylase. Fe3O4/g‐C3N4 nanocomposite was fabricated by introducing iron oxide into g‐C3N4 nanosheets. Formation of Fe−N bonds with structure resembled the active center. The nanozyme possessed superparamagnetic characteristics and wide light response range. The nanozyme exhibited similar activity as tyrosine hydroxylase by catalyzing hydroxylation of tyrosine in the presence of visible light irradiation and hydrogen peroxide. Maximum yield and titer was obtained as 15% and 1 mM for production of L‐DOPA, respectively. The nanozyme demonstrated high stability and reusability. The nanozyme catalyzed the reaction in an analogous mechanism with FeIVO2+ as the dominant active species. It might provide a promising insight to produce L‐DOPA due to advantages of easy separation and mild conditions.

Fabrication of 0D/1D/2D ZnS–CuS nanodots/GNRs/g-C3N4 heterojunction photocatalyst for efficient photocatalytic overall water splitting

Photocatalytic water splitting has become a significant challenge in modern chemistry. In this process, the rate-determining step is the hydrogen evolution reaction (HER). In the present work, a surface modification approach for graphitic carbon nitride (g-C3N4) was applied to improve its photocatalytic HER. 0D ZnS–CuS nanodots were synthesized with the hydrothermal method as a co-catalyst to enhance the capability and stability of water splitting in the presence of visible light irradiation. Also, graphene nanoribbons were synthesized from CNTs unzipping to reduce the energy barrier of HER, improve the HE kinetic, and enhance the catalytic performance of the g-C3N4. By using ZnS–CuS/GNRs(2)/g-C3N4 photocatalyst, a low onset potential of 130 mV, slight Tafel slope of 41 mV dec−1, as well as excellent stability of 2000 s was obtained in acidic media. This efficient performance is attributed to the increased visible light absorption level in the proposed photocatalyst and the high stability in electron-hole pairs.

Toward enhanced visible-light photocatalytic dye degradation and reusability of La3+ substituted ZnFe2O4 nanostructures

The present work focused on the synthesis of novel ZnLaxFe2−xO4 catalysts (x = 0, 0.01, 0.03, 0.05) and their utilization for the photocatalytic degradation of Rhodamine B dye. Structurally, the band gap energy of the catalysts tended to decrease (1.94–1.70 eV) with increasing the amount of La3+ dopant. ZnLa0.05Fe1.95O4 had an average particle size (40 nm), high surface area (41.07 m2 g−1) and large pore volume (0.186 cm3 g−1). Moreover, the effect of doping ratio, reaction time, H2O2 concentration, catalyst loading on the treatment performance of La3+ substituted ZnFe2O4 nanocomposites was investigated. ZnLa0.05Fe1.95O4/H2O2 system exhibited the highest degradation efficiency of 99.5% and nonlinear pseudo first-order kinetic reaction rate (14.8 × 10−3 min−1) in the presence of visible light irradiation. The key role of reactive oxygen species involving •O2− and •OH radicals was well explained through the scavenger study. A plausible mechanism of the degradation of Rhodamine B dye was also proposed. Due to two advantageous points including high recyclability (up to 4 cycles) and stability, La3+ substituted ZnFe2O4 nanocomposites can be an effective and competitive catalyst for the visible light-driven photodegradation of toxic dyes in the real wastewaters.