Controlling the charge carriers recombination kinetics on the g-C3N4-BiSI n-n heterojunction with efficient photocatalytic activity in N2 fixation and degradation of MB and phenol

The challenges like the photocatalytic reduction of N₂ and elimination of contaminants from the wastewater are accessible by low cost, stable, and visible-light-driven semiconductor-based photocatalysis. A novel g-C₃N₄/BiSI nanocomposite was synthesized by hydrothermal method and applied for the first time in photocatalytic nitrogen fixation and degradation of methylene blue dye and phenol. The physicochemical features of the photocatalysts were studied by XRD, XPS, FTIR, BET, DRS, FESEM, TEM, EDX mapping, PL, EIS, Mott-Schottky, and photocurrent techniques. Experimental results showed that the production of ammonia in the presence of g-C₃N₄/BiSI nanocomposite was 1280 μmol L^?1 g^?1, while this values for g-C₃N₄ and BiSI were 274 μmol g^?1 L^?1 and 126 μmol g^?1 L^?1, respectively. Moreover prepared nanocomposite exhibited a higher rate constant in the MB (537.5 × 10^?4 min^?1) and phenol (353 × 10^?4 min^?1) degradation compared with the counterparts. The charge separation efficiency obviously improved, which was ascribed to the charges migration between g-C₃N₄ and BiSI in an n-n heterojunction system. In addition, high specific surface area and strong visible light absorption were identified as other factors affecting photocatalytic performance. This unique heterojunction photocatalyst has wide application prospects in environmental treatment.     

Synthesis and characterization of Bi2MoO6/MIL-101(Fe) as a novel composite with enhanced photocatalytic performance: Effect of water matrix and reaction mechanism

The integration of Bi₂MoO₆ with MIL-101(Fe) as a novel structure enhanced photocatalytic activity for RhB degradation. Bi₂MoO₆/MIL-101(Fe) composites were synthesized via the solvothermal procedure and characterized by XRD, EDX, FE-SEM, TEM, FT-IR, BET, TGA, UV–vis DRS, and PL. The optimal molar ratio Bi₂MoO₆:MIL-101(Fe) equal to 1:1 showed better photocatalytic activity than Bi₂MoO₆ and MIL-101(Fe) and other heterostructure composites. The effect of pH (5–9), reaction time (60–120 min), catalyst concentration (0.1–0.5 g/L), and dye concentration (10–20 ppm) were investigated on the removal performance of RhB by using central composite face-centered (CCF). In the optimal process factors where the [Catalyst]:0.4 g/L, [RhB]:20 ppm, pH: 6.5, irradiation time: 120 min, the RhB and TOC removal efficiency were 85% and 84.2%, respectively. The holes and superoxide radicals played a major role in the degradation of RhB. The addition of salt (NaCl, Na₂SO₄, and NaHCO₃) at different concentrations (100, 200, 400, and 800 ppm) revealed that the salts have an inhibitory role in the photocatalytic performance. At low concentrations of 100 ppm, the salts had a negative effect on removal efficiency (k_{Pure water} = 0.0155 min^?1, k_NaCl = 0.0075 min^?1, k_Na2SO4 = 0.0132 min^?1, k_NaHCO3 = 0.006 min^?1). Increasing the salt concentration to 800 ppm caused improved efficiency for NaCl (k_NaCl = 0.0141 min^?1), while for Na₂SO₄ this trend was decreasing (k_Na2SO4 = 0.011 min^?1), and for NaHCO₃ sharply diminished (k_NaHCO3 = 0.0026 min^?1).     

The fast degradation for tetracycline over the Ag/AgBr/BiOBr photocatalyst under visible light

A series of Ag/AgBr/BiOBr photocatalysts with different weight contents of Ag/AgBr were successfully constructed via a simple precipitation method in 80 °C water bath. Photocatalysts were characterized by XRD, XPS, SEM, TEM, N₂ Adsorption-Desorption (BET), and UV–Vis Diffuse Reflectance Spectroscopy (DRS). Compared with BiOBr and Ag/AgBr, all the composite photocatalysts show the prominent photocatalytic activity for the degradation of tetracycline (TC). Especially, 1:5Ag/AgBr/BiOBr (20%) has the highest reaction rate constant (kapp?=?0.20 min^?1). Moreover, according to the results of radical scavengers runs, ·OH and h⁺ acted as the main reactive species in the degradation process. Based on above, a possible photocatalytic mechanism for organics degradation over Ag/AgBr/BiOBr was proposed. Interestingly, the redox cycle between O₂/·O₂^? and Br^?/Br⁰ assisted with the surface plasmon resonance (SPR) effect of silver dramatically promotes the separation and transfer of electron–hole pairs, and improves the photocatalytic activity of the as-obtained composite samples.

     

PH-induced structural evolution,photodegradation mechanism and application of bismuth molybdate photocatalyst

In this work, we have elucidated the pH-induced structural evolution of bismuth molybdate photocatalyst based on a hydrothermal synthesis route. With increasing the pH value of precursor solution, pure Bi₂MoO₆ was synthesized at pH 2–5, Bi₂MoO₆-Bi₄MoO₉ mixture was obtained at pH 7–9, pure Bi₄MoO₉ was obtained at pH 11, and pure α-Bi₂O₃ was derived at pH 13. The as-derived samples mainly present particle-like shapes but with different particle sizes (except the observation of Bi₂MoO₆ nanowires in sample S-pH9). The photocatalytic performances between the samples were compared via the degradation of methylene blue (MB) under irradiation of simulated sunlight. The Bi₂MoO₆ sample synthesized at pH 2 exhibited the highest photodegradation performance (η(30 min) = 89.8 %, k_app = 0.05007 min^?1) among the samples. The underlying photocatalytic mechanism and degradation pathways of MB were systematically analyzed. Moreover, the photodegradation performance of the Bi₂MoO₆ photocatalyst was further evaluated at different acidic-alkaline environments as well as in degrading various color and colorless organic pollutants, which provides an important insight into its practical application.     

High performance magnetically recoverable g-C3N4/Fe3O4/Ag/Ag2SO3 plasmonic photocatalyst for enhanced photocatalytic degradation of water pollutants

The g-C₃N₄/Fe₃O₄/Ag/Ag₂SO₃ nanocomposites have been successfully fabricated by facile refluxing method. The as-obtained products were characterized by XRD, EDX, SEM, TEM, UV–vis DRS, FT–IR, TGA, PL, and VSM techniques. The results suggest that the Ag/Ag₂SO₃ nanoparticles have anchored on the surface of g-C₃N₄/Fe₃O₄ nanocomposite, showing strong absorption in the visible region. The evaluation of photocatalytic activity indicates that for the g-C₃N₄/Fe₃O₄/Ag/Ag₂SO₃ (40%) nanocomposite, the degradation rate constant was 188 × 10^?4 min^?1 for rhodamine B, exceeding those of the g-C₃N₄ (16.0 × 10^?4 min^?1) and g-C₃N₄/Fe₃O₄ (20.2 × 10^?4 min^?1) by factors of 11.7 and 9.3, respectively. The results showed that the nanocomposite prepared by refluxing for 120 min has the superior photocatalytic activity and its activity decreased with rising the calcination temperature. The trapping experiments confirmed that superoxide ion radical was the main active species in the photocatalytic degradation process. Also, it was demonstrated that the magnetic photocatalyst has considerable activity in degradation of one more dye pollutant. Finally, the reusability of the photocatalyst was evaluated by five consecutive catalytic runs. This work may open up new insights into the utilization of magnetically separable nanocomposites and provide new opportunities for facile fabrication of g-C₃N₄-based plasmonic photocatalysts.     

Biomimetic Photocatalytic System Designed by Spatially Separated Cocatalysts on Z-scheme Heterojunction with Identified Charge-transfer Processes for Boosting Removal of U(VI)

Designing highly efficient photocatalysts with rapid migration of photogenerated charges and surface reaction kinetics for the photocatalytic removal of uranium (U(VI)) from uranium mine wastewater remains a significant challenge. Inspired by natural photosynthesis, a biomimetic photocatalytic system is assembled by designing a novel hollow nanosphere MnO_x@TiO₂@CdS@Au (MTCA) with loading MnO_x and Au nano particles (Au NPs) cocatalysts on the inner and outer surfaces of the TiO₂@CdS. The spatially separated cocatalysts efficiently drive the photogenerated charges to migrate in opposite directions, while the Z-scheme heterogeneous shell further separates the interfacial charges. Theoretical calculation identifies multiple consecutive forward charge transfers without charge recombination within MTCA. Thus, MTCA could efficiently remove 99.61% of U(VI) after 15 min of simulated sunlight irradiation within 3 mmol L⁻¹ NaHCO₃ with 0.231 min⁻¹ of the reduction rate constant, outperforming most previously reported photocatalysts. MTCA further significantly removes 91.83% of U(VI) from the natural uranium mining wastewater under sunlight irradiation. This study provides a novel approach to designing an ideal biomimetic photocatalyst for remediating environmental pollution.     

Fabrication of Bi2WO6/In2O3 photocatalysts with efficient photocatalytic performance for the degradation of organic pollutants: Insight into the role of oxygen vacancy and heterojunction

Photocatalysis is an attractive and green strategy for organic pollutant removal. The development of alternative and effective photocatalysts has attracted great attention. Herein, we rationally engineer an alternative rich-oxygen vacancies (OVs) Bi₂WO₆/In₂O₃ composite photocatalyst via integrating the calcination and hydrothermal method for removing organic dyes (rhodamine B). Thanks to the synergistic effect of OVs and heterojunction structure, the 80 wt% Bi₂WO₆/In₂O₃ (BiIn80) displays enhanced photocatalytic degradation effect. The degradation rate of BiIn80 is up to 97.3% under light irradiation within 120 min and the reaction rate constant k value (0.03221 min⁻¹) is about 15-fold and 4.17-fold as high as those of In₂O₃ (0.00203 min⁻¹) and Bi₂WO₆ (0.00772 min⁻¹), respectively. The heterostructure of Bi₂WO₆/In₂O₃ can extend the lifespan of the photogenerated charge carriers. Moreover, the density functional theory (DFT) calculations reveal that the OVs in Bi₂WO₆/In₂O₃ can boost visible light absorbability by decreasing band gap value and serve as the extra electron transfer channels to enhance the separation efficiency of photogenerated electron-hole pairs. This study not only provides an alternative route for fabricating highly efficient heterojunction photocatalysts, but also obtains better understanding of the synergistic effect of OVs and heterojunction on enhancing the photocatalytic performance.     

Controlled synthesis of mesoporous α-Fe2O3 nanorods and visible light photocatalytic property

Porous α-Fe₂O₃ nanorods with typical pore size of 2–4 nm were controlled prepared by a facile hydrothermal process of Fe(NO₃)₃·9H₂O aqueous solution in the presence of NaOH, followed by a calcination treatment. Contrast experiments indicate that the morphology and crystalline structure of the hydrothermal products depend greatly on the quantity of NaOH. Hematite nanoparticles and microplates were respectively obtained under conditions without or with excess NaOH. The porous α-Fe₂O₃ nanorods exhibit a high BET surface area of 105.1 m² g^?1 and a pore volume of 0.13 m³ g^?1. UV–vis measurement shows wide absorption to visible light and an obvious blue-shift of the adsorption edge due to the quantum size effect. The visible-light photocatalytic performances of the as-prepared samples were evaluated by photocatalytic decolorization of methylene blue at ambient temperature. The results indicate that the photocatalytic activity of the porous α-Fe₂O₃ nanorods is superior to hematite nanoparticles and platelets and exhibit good reusable feature. The photocatalytic process of porous structure is determined to be pseudo-first-order reaction with apparent reaction rate constant of 1.04 × 10^?2 min^?1. And the optimum photocatalyst dosage is 20 mg per 100 mL of dye solution. The porous α-Fe₂O₃ nanorods are considered potential photocatalyst for practical application due to the excellent photocatalytic behavior and good reusability.     

Oxygen-vacancy-rich Ag/Bi5O7Br nanosheets enable improved photocatalytic NO removal and oxygen evolution under visible light exposure

Photocatalytic NO removal is a green and sustainable alternative to the conventional thermocatalysis in the conversion of NO to nitrates. However, the efficiency of photocatalytic NO removal is restricted by weak NO adsorption and high charge recombination on photocatalyst. Herein, we report on one-step synthesis of Ag/Bi₅O₇Br nanosheets with rich oxygen vacancies (OVs) by a facile liquid phase reduction method. Under visible light irradiation on oxygen-vacancy-rich Ag/Bi₅O₇Br for 50 min the photocatalytic NO removal ratio is up to 64.65%, which is about 1.6 times higher than that by using pristine Bi₅O₇Br. The average oxygen production rate is 823 μmol·g^?1·h^?1, which is nearly 10 times higher than that of Bi₅O₇Br. Density functional theory (DFT) calculations reveal that OVs incorporation and plasmonic Ag can synergistically strengthen NO adsorption on Bi₅O₇Br. This work highlights the great potential of defects and plasmonic metals on synergistic enhancement in photocatalytic NO removal and oxygen evolution.     

Preparation of a 3D flower-like spherical structure g-C3N4/CuBi2O4/Bi2MoO6 photocatalyst for efficient removal of antibiotics under visible light

For the remediation of antibiotic-contaminated water bodies, this study synthesized g-C₃N₄/CuBi₂O₄/Bi₂MoO₆ 3D flower-like spherical photocatalysts by a solvothermal method. The tetracycline antibiotics were used as the target pollutants and degraded under visible light to evaluate the photocatalytic performance of the prepared photocatalysts. Notably, the g-C₃N₄/CuBi₂O₄/Bi₂MoO₆ photocatalyst achieved 84.6 % and 91.6 % for the degradation of tetracycline hydrochloride and chlortetracycline (100 mL, 20 mg/L), respectively, within 2 h under visible light irradiation. Furthermore, we found that the composites showed very low degradation rates for dye-based contaminants, but still exhibited excellent photocatalytic activity for antibiotics in a mixed contaminant system of dyes and antibiotics. And the intermediate was detected by gas chromatography-mass spectrometry (GC–MS), suggesting a possible photo-degradation pathway for tetracycline. Finally, biochemical experiments were carried out to further illustrate the effective degradation of antibiotics in water after photocatalytic degradation by observing and comparing the growth of mung bean seeds.     

Novel Mo/Bi2MoO6/Bi3ClO4 heterojunction photocatalyst for ultra-deep desulfurization of thiophene under simulated sunlight irradiation

In the present work, a visible-light-driven Mo/Bi₂MoO₆/Bi₃ClO₄ heterojunction photocatalyst was fabricated via the Pechini sol–gel process. The type and amount of gelling agent, chelating agent and mole ratio of chelating agent to total metals were balanced to generate ultrafine nanoparticles. The Mo/Bi₂MoO₆/Bi₃ClO₄ nanocomposite as a novel photocatalyst not only exhibited an excellent visible-light photocatalytic desulfurization performance of thiophene (~97%), but also had better photodesulfurization efficiency than Mo/Bi₂MoO₆ and Bi₃ClO₄ nanostructures. The ultra-deep photocatalytic desulfurization performance of the Mo/Bi₂MoO₆/Bi₃ClO₄ nanocomposite can be attributed to the strong visible-light absorption, unique nanostructures, high separation and low recombination of electron–hole pairs due to the as-formed heterojunctions. Furthermore, a photocatalytic desulfurization mechanism was elucidated via radical trapping experiments, which revealed that the ^?O₂^? and ^?OH radicals play a key role in the photocatalytic desulfurization process.     

The Ag-based SPR effect drives effective degradation of organic pollutants by BiOCOOH/AgBr composites

The easy recombination of electron-hole pairs produced by monomeric photocatalysts under light exposure severely limits their application in wastewater treatment. Based on this, BiOCOOH/Ag/AgBr ternary photocatalysts in flower-like microspheres were controllably synthesized by precipitation photoreduction and characterized by various techniques. In addition, the effects of different molar ratio of BiOCOOH and AgBr, catalyst dose, pH and coexisting ions on the photocatalytic degradation of rhodamine B (RhB) and tetracycline (TC) were investigated. The results showed that the BOC/Ag/AgBr-0.5 composite exhibited excellent photocatalytic activity for the degradation of RhB and TC. The excellent photocatalytic activity was mainly attributed to the surface plasmon resonance (SPR) effect of metallic Ag and charge transfer mechanism between composites, thus promoting charge separation. The degradation efficiency of RhB and TC was 92.7% and 72.3% with the degradation rate constant of 0.073 and 0.023 under light irradiation of xenon lamp in 30 and 45 min, respectively, which was 6 and 2 times higher than that of BiOCOOH and AgBr. The stability studies showed that BOC/Ag/AgBr-0.5 maintained a high catalytic activity after four cycles. The results of radical capture experiments showed that h⁺ and ·O₂^– were the main reactive radicals, while ·OH played a secondary role in the photocatalytic system. Subsequently, a potential photocatalytic mechanism was proposed based on the experimental results.     

A novel 0.9KNbO3–0.1BaNi0.5Nb0.5O3(KBNNO):Ag2O/Bi2O3 heterojunction photocatalyst: synthesis,characterization and excellent photocatalytic performance

In the present study, first 0.9KNbO₃–0.1BaNi_0.5Nb_0.5O₃(KBNNO) nanosized powder was synthesized by solution combustion method and then a series of KBNNO:Ag₂O and KBNNO:Bi₂O₃ composites with varying weight ratios (75:25, 50:50, and 25:75) were prepared by a simple precipitation technique/solid-state method. Preparation method and processing temperature have significant effect on phase stability and interface formation. The structural, morphological and photoabsorption behaviour of the synthesized powders were studied systematically by XRD, TEM, XPS and UV–visible spectroscopy. The photocatalytic performance of the photocatalysts was evaluated for the degradation of rhodamine B (RhB) solution under visible light exposure. In particular, KBNNO:Ag₂O composites exhibited better photodegradation of RhB. KBNNO:Ag₂O (50:50) nanocomposite can completely mineralize the RhB in 25 min, whereas KBNNO:Bi₂O₃ (25:75) can mineralize 96% of RhB in 45 min. The rate constant (k) for dye degradation of KBNNO:Ag₂O (50:50) (0.113 min^?1) sample showed the highest value which was 4.71 and 5.94 times better than that of KBNNO and Ag₂O under visible light irradiation. The rate constant for KBNNO:Bi₂O₃ (25:75) (0.048 min^?1) exhibited the highest k value which is 1.94 and 3.13 times greater than that of KBNNO and Bi₂O₃ under similar irradiation condition. The significant absorption in visible region and reduced recombination time of charge carriers in the composite than the parent materials were responsible for excellent photocatalytic properties. The mechanism for degradation was also studied in detail. Moreover, a reasonable degradation of 95% (on an average) was observed after five cycles, suggesting a good photocatalytic stability of the composites.

     

Fabrication and characterization of electrospun Ag doped TiO2 nanofibers for photocatalytic reaction

Titanium dioxide is one of the best semiconductor photocatalysts available for photocatalytic reaction of dye pollutants. To prevent the recombination caused by the relatively low photocatalytic efficiency, Ag doped TiO₂ nanofiber was prepared by electrospinning method. The photocatalysts (pure TiO₂ nanofiber and Ag doped TiO₂ nanofiber) were characterized by FE-SEM, XRD, XPS, and PL analysis. These photocatalysts were evaluated by the photodecomposition of methylene blue under UV light. Ag doped TiO₂ nanofiber was found to be more efficient than pure TiO₂ fiber for photocatalytic degradation of methylene blue. The photocatalytic degradation rate was applied to pseudo-first-order equation. The degradation of Ag doped TiO₂ nanofiber was significantly higher than the degradation rate of pure TiO₂ nanofiber. Activation energy was calculated by applying Arrhenius equation from the rate constant of photocatalytic reaction. The activation energies for the pure TiO₂ nanofibers calcined at 400 and 500 °C were 16.981 and 12.187 kJ/mol and those of Ag doped TiO₂ nanofibers were 18.317 and 7.977 kJ/mol, respectively.     

Mesoporous Polymeric Cyanamide‐Triazole‐Heptazine Photocatalysts for Highly‐Efficient Water Splitting

Conjugated polymers are promising light harvesters for water reduction/oxidation due to their simple synthesis and adjustable bandgap. Herein, both cyanamide and triazole functional groups are first incorporated into a heptazine‐based carbon nitride (CN) polymer, resulting in a mesoporous conjugated cyanamide‐triazole‐heptazine polymer (CTHP) with different compositions by increasing the quantity of cyanamide/triazole units in the CN backbone. Varying the compositions of CTHP modulates its electronic structures, mesoporous morphologies, and redox energies, resulting in a significantly improved photocatalytic performance for both H₂ and O₂ evolution under visible light irradiation. A remarkable H₂ evolution rate of 12723 µmol h^?1 g^?1 is observed, resulting in a high apparent quantum yield of 11.97% at 400 nm. In parallel, the optimized photocatalyst also exhibits an O₂ evolution rate of 221 µmol h^?1 g^?1, 9.6 times higher than the CN counterpart, with the value being the highest among the reported CN‐based bifunctional photocatalysts. This work provides an efficient molecular engineering approach for the rational design of functional polymeric photocatalysts.     

Preparation of nitrogen-doped aluminium titanate (Al2TiO5) nanostructures: Application to removal of organic pollutants from aqueous media

Recently, aluminum titanate (Al₂TiO₅)-based nanostructures have been proved to serve as an efficient photocatalytic material with satisfactory photodegradation capacity. In this study, the citrate sol–gel method was used to synthesize these nanostructures and inspect the significant impacts of nitrogen-doping-originated crystalline defects on their photocatalytic performance in some details for the first time. The results indicated that the penetration of nitrogen atoms into AT crystal lattice, depending on the nitriding time and temperature, can induce a great deal of the residual stress and result in propagating the existing cracks and breaking down the particles. The XPS and FTIR results confirmed the formation of some new bonds in the crystal structure (including O-Ti-N and Ti-N), the substitutional and interstitial replacement of nitrogen atoms with oxygen atoms, oxygen vacancies, and the attachment of nitrogen species at superficial oxygen sites. These events may vary the bandgap values from 2.88 eV for pristine AT to 2.73 eV for the nitrided one, thereby manipulating the charge carrier recombination rate and activation of superficial catalytic reactions in the particles. Numerically, the band structure variations can efficiently increase the photodegradation efficiency of methylene blue (MB) and apparent rate constant (k) by 1.4 times (from 38.9 to 55.9%) and 1.8 times (from 0.0038 to 0.0068 min⁻¹), respectively. Finally, the results show that the synthesized photocatalyst can successfully compete with TiO₂-based photocatalysts in terms of photocatalytic performance.     

Enhanced photocatalytic activity of Fe3O4-WO3-APTES for azo dye removal from aqueous solutions in the presence of visible irradiation

Development of highly active photocatalysts for treatment of dye-laden wastewaters is vital. The photocatalytic removal of azo dye Reactive Black 5 was investigated by Fe₃O₄-WO₃-3-aminopropyltriethoxysilane (APTES) nanoparticles in the presence of visible light. The Fe₃O₄-WO₃-APTES nanoparticles were synthesized via a facile coprecipitation method. The photocatalyst was characterized by XRD, FT-IR, SEM, EDX, VSM, UV–Vis, and pH_PZC techniques. The effects of some operational parameters such as solution pH, nanophotocatalyst dosage, initial RB5 concentration, H₂O₂ concentration, different purging gases, and type of organic compounds on the removal efficiency were studied by the Fe₃O₄-WO₃-APTES nanoparticles as a photocatalyst. Maximum phtocatalytic activity was obtained at pH 3. The photocatalytic removal of RB5 increased with increasing H₂O₂ concentration up to 5?mM. The removal efficiency declined in the presence of different purging gases and all types of organic compounds. First-order rate constant (k_obs) decreased from 0.027 to 0.0022?min^?1 and electrical energy per order (E_Eo) increased from 21.33 to 261.82 (kWh/m³) with increasing RB5 concentration from 10 to 100?mg/L, respectively. The efficiency of LED/Fe₃O₄-WO₃-APTES process for RB5 removal was approximately 89.9%, which was more effective than the LED/Fe₃O₄-WO₃ process (60.72%). Also, photocatalytic activity decreased after five successive cycles.     

The mechanism insight for improved photocatalysis and interfacial charges transfer of surface-dispersed Ag0 modified layered graphite-phase carbon nitride nanosheets

A series of surface-dispersed Ag⁰ modified lamellar-graphite-phase carbon nitride nanosheets (Ag/LGCNs) are synthesized by a straightforward method to construct the noble metal/semiconductor heterojunction. The localized surface plasmon resonance (LSPR) effect results in an optimum degradation rate (K_app) for rhodamine B ～ 5.53 × 10^?2?min^?1 (9 times higher than that of pure LGCNs), and the sample exhibited outstanding stability. The experiments with sacrificial reagents showed that the h⁺ and ?O₂^– are primary active photocatalytic species in the present samples. The optical and photo-electro-chemical studies of the samples, confirm enhanced photo-responsiveness and photogenerated carriers' separation and transport with an appropriate amount of Ag⁰. The corresponding mechanism is formulated using photocurrent analysis, impedance analysis, finite-difference time-domain (FDTD) simulation and density functional theory (DFT). FDTD simulation evidenced an intense electromagnetic field at the Ag/LGCN’s interface under visible radiation attributable to the LSPR effect of Ag⁰ nanoparticles and an increased field intensity with the size of Ag⁰ nanoparticles. The DFT computations show that the difference in Fermi energy level and the work function contributes to an interfacial built-in electric field between Ag⁰ nanoparticles and LGCNs. Furthermore, the mechanism for reduced band gap and improved photocatalytic performance for Ag/LGCNs is explained by the energy band studies.     

Crafting Mussel‐Inspired Metal Nanoparticle‐Decorated Ultrathin Graphitic Carbon Nitride for the Degradation of Chemical Pollutants and Production of Chemical Resources

The development of efficient photocatalysts for the degradation of organic pollutants and production of hydrogen peroxide (H₂O₂) is an attractive two‐in‐one strategy to address environmental remediation concerns and chemical resource demands. Graphitic carbon nitride (g‐C₃N₄) possesses unique electronic and optical properties. However, bulk g‐C₃N₄ suffers from inefficient sunlight absorption and low carrier mobility. Once exfoliated, ultrathin nanosheets of g‐C₃N₄ attain much intriguing photocatalytic activity. Herein, a mussel‐inspired strategy is developed to yield silver‐decorated ultrathin g‐C₃N₄ nanosheets (Ag@U‐g‐C₃N₄‐NS). The optimum Ag@U‐g‐C₃N₄‐NS photocatalyst exhibits enhanced electrochemical properties and excellent performance for the degradation of organic pollutants. Due to the photoformed valence band holes and selective two‐electron reduction of O₂ by the conduction band electrons, it also renders an efficient, economic, and green route to light‐driven H₂O₂ production with an initial rate of 0.75 × 10^?6 m min^?1. The improved photocatalytic performance is primarily attributed to the large specific surface area of the U‐g‐C₃N₄‐NS layer, the surface plasmon resonance effect induced by Ag nanoparticles, and the cooperative electronic capture properties between Ag and U‐g‐C₃N₄‐NS. Consequently, this unique photocatalyst possesses the extended absorption region, which effectively suppresses the recombination of electron–hole pairs and facilitates the transfer of electrons to participate in photocatalytic reactions.     

Preparation,characterization, and photocatalytic activity of novel AgBr/ZIF-8 composites for water purification

A highly efficient photocatalyst, AgBr coupled zeolitic imidazolate framework-8 (AgBr/ZIF-8) hybrid, was prepared for photocatalytic degradation of dyes under illumination of visible light. The hybrid structure of AgBr and ZIF-8 was confirmed via X-ray diffraction (XRD). Meanwhile, metal Ag was also detected via X-ray photoelectron spectroscopy (XPS), indicating that the real composition of the complex is Ag-AgBr-ZIF-8. N₂-adsorption, UV–visible diffuse reflection spectroscopy (DRS), transient photocurrent (PC), electrochemical impedance spectroscopy (EIS) and linear sweep voltammetry (LSV) analyses were performed to reveal the influence of the added AgBr on the specific surface area, charge separation efficiency and optical property of ZIF-8. Results indicated that the photoabsorption performance and the specific surface area of the AgBr/ZIF-8 composite are between that of pure AgBr and ZIF-8. Nevertheless, the synergy of ZIF-8 and AgBr in separating electrons and holes was observed, which induced significantly improved efficiency in charge separation, and subsequently resulted in the enhanced photoactivity of the AgBr/ZIF-8 composite. The performance evaluation demonstrated that the optimized AgBr/ZIF-8 presented a methylene blue (MB) degradation rate of 0.0273 min⁻¹, which was 3.59 times as high as that of AgBr. Additionally, the composite also worked well in photocatalytic decomposition of methyl orange (MO) and rhodamine B(RhB) under visible light. The degradation efficiency reached to 99.5% under visible light irradiation for 60 min. This work provides a hybrid photocatalyst with high efficiency, and may shed some light on the application of MOF-based composite in photocatalytic field.