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Visible-Light-Driven Photocatalytic Z-scheme Overall Water Splitting in La5Ti2AgS5O7-based Powder Suspension System
摘要： La5Ti2CuxAg1-xS5O7 (x=0-1) is a kind of long-wavelength-responsive oxysulfide photocatalysts for hydrogen evolution, and has been demonstrated to enable the Z-scheme water splitting coupling with oxygen evolution photocatalysts (OEP) the particulate sheet. We herein report that among La5Ti2CuxAg1-xS5O7, La5Ti2AgS5O7 was found to have the highest performance on Z-scheme overall water splitting in conjunction with PtOx-WO3 as an OEP, and a triiodide/iodide (I3?/I?) redox couple as a shuttle electron mediator in powder suspension system. Loading Pt/NiS on La5Ti2AgS5O7 benefits the Z-scheme to achieve an apparent quantum yield of 0.12% at 420 nm. The finding in powder suspension system is opposite to the earlier study on photocatalyst sheet configurations in which p-type doping and the formation of a solid solution can effectively enhance the water-splitting activity. This work not only shows a La5Ti2AgS5O7-based Z-scheme water splitting photocatalyst, but also may present a better understanding for the difference between particulate sheet and powder suspension system available in an optimal strategy for water splitting.
关键词： photocatalysis,water splitting,visible light,Z-scheme,oxysulfides
更新于2025-09-23 15:22:29
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Ag3PO4 modified phosphorus and sulphur co-doped graphitic carbon nitride as a direct Z-scheme photocatalyst for 2, 4-dimethyl phenol degradation
摘要： Very recently, hybrid photocatalysts are gaining importance due to their unique and enhanced photocatalytic activity. In precedent study, we have successfully prepared Ag3PO4 (AP) and P and S co-doped g-C3N4 (PSGCN) based AP/PSGCN photocatalyst via facile deposition-precipitation method. The P and S co-doped g-C3N4 was prepared via thermal poly-condensation using hexachlorotriphosphazene (HCCP) and thiourea as precursors. The photocatalysts were characterized by X-ray diffraction pattern (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectra (FTIR), X-ray photoelectron spectroscopy (XPS), Brunauer-Emmett-Teller (BET) and ultraviolet–visible diffuse reflectance spectroscopy (UV–Vis DRS). The thickness of AP/PSGCN was less than 9.0 nm. The zeta potential and Tyndall effect experiments validated the formation of well dispersed suspension of AP/PSGCN in water. The co-doping resulted in lowering of optical band gap of g-C3N4. The Tyndall effect experiments ascertained the formation of well dispersed suspension of AP/PSGCN. The photoluminescence and electrochemical impedance analysis confirmed reduction in recombination of photogenerated electron and hole pairs. The photodegradation of 2,4-dimethyl phenol (DMP) followed pseudo first order kinetics. The enhanced photocatalysis was due to direct Z-scheme mechanism. Hydroxyl and superoxide radicals were the two main reactive species during DMP degradation. The COD, HPLC and LC-MS investigations ascertained mineralization of DMP. AP/PSGCN displayed high stability and recycle efficiency significant for ten catalytic cycles.
关键词： DMP,Ag3PO4,P and S Co-doped g-C3N4,Nanocomposite,Z-scheme photocatalysis
更新于2025-09-23 15:22:29
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[IEEE 2018 International Multi-Conference on Industrial Engineering and Modern Technologies (FarEastCon) - Vladivostok, Russia (2018.10.3-2018.10.4)] 2018 International Multi-Conference on Industrial Engineering and Modern Technologies (FarEastCon) - The Increase of the Effectiveness of the Autonomous System of Solar Energy Supply
摘要： For the effective heat supply of the consumers the solar energy is viewed with the aim of replacing the organic fuel the costs on which constantly increase. The analysis of the existing solar collectors as the basic element of the system of solar heat supply and its factors for the increase of the effectiveness of its usage is shown. The interconnection of constructive and regime parameters of solar collectors and the necessity of the regulating the regime of their work for the effectiveness of the system of solar heat supply as a whole are also shown. To achieve the formulated purpose the regulating of the scheme of the connection of solar collectors between them is offered and as the source of power supply the solar battery is suggested for providing the autonomy of the system of solar heat supply. The principle of the control of the scheme of the connecting of solar collectors and the description of the regime of work of the suggested device are examined. The block scheme of the algorithm of control for providing the given parameters of regulating is worked out and shown.
关键词： system of solar heat supply,parameters of solar collector,algorithm of control,scheme of the connection of the collectors,solar collector,solar battery,solar radiation
更新于2025-09-23 15:22:29
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New Optical Properties of Ice Crystals for Multi-Class Cloud Microphysics
摘要： New optical properties of ice crystals were implemented in a general circulation model (GCM). Ebert and Curry’s (1992) and Fu’s (1996) parametrizations are widely used in the GCM radiation scheme. However, the validity of the data is limited to an effective radius (size) of 130 or 140 μm. This limit exceeds the median of the effective radius of snow (~200 μm), which is computed from the multi-class cloud microphysics scheme. A comparable amount of snow exists in the upper atmosphere near the lower part of ice clouds. Although the cross section of snow (extinction probability) is smaller than cloud ice, its impact on radiation has not been properly considered so far. We constructed a new lookup table of optical properties based on recent data for an extended effective radius up to 500 μm. The old data (< 130 μm) also need to be updated with a more recent and elaborate method. We processed extensive data provided by Yang et al. (2013) and linked to the radiation module of the Korean Integrated Model (KIM). The new optical properties change the shortwave scattering features, thus increasing the heating rate. This tendency is checked in both one-dimensional and global weather forecast simulations. With the new optical properties, KIM shows better performance by reducing bias with respect to the Integrated Forecasting Systems (IFS) analysis data.
关键词： weather forecasting,optical properties,cloud microphysics,ice crystals,radiation scheme
更新于2025-09-23 15:21:21
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Bio-inspired Z-scheme g-C3N4/Ag2CrO4 for efficient visible-light photocatalytic hydrogen generation
摘要： Due to low charge separation efficiency and poor stability, it is usually difficult for single-component photocatalysts such as graphitic carbon nitride (g-C3N4) and silver chromate (Ag2CrO4) to fulfill photocatalytic hydrogen production efficiently. Z-scheme charge transport mechanism that mimics the photosynthesis in nature is an effective way to solve the above problems. Inspired by photosynthesis, we report Ag2CrO4 nanoparticles-decorated g-C3N4 nanosheet as an efficient photocatalyst for hydrogen evolution reaction (HER) with methanol as sacrificial agent. The formation of Z-scheme g-C3N4/Ag2CrO4 nanosheets photocatalysts could inhibit the recombination of photogenerated electron-hole pairs, promote the generation of hydrogen by photosplitting of water. The experiment results indicate that g-C3N4/Ag2CrO4 nanocomposites present enhanced photocatalytic activity and stability in the H2 evolution of water splitting. And the nanocomposites g-C3N4/Ag2CrO4(23.1%) show the 14 times HER efficiency compared to that of bare g-C3N4.
关键词： visible-light,Z-scheme,hydrogen production,g-C3N4,Ag2CrO4,photocatalysts
更新于2025-09-23 15:21:21
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Two-dimensional g-C3N4/TiO2 Nanocomposites as Vertical Z-scheme Heterojunction for Improved Photocatalytic Water Disinfection
摘要： Developing highly active photocatalysts towards effective microorganism inactivation is a green and energy-smart strategy in response to the growing demands to water quality under the background of the water crisis. Here, a vertical face-to-face heterojunction was fabricated by horizontally assembling TiO2 nanosheets with {001} facets exposed on graphitic carbon nitride (g-C3N4) sheets through a facile hydrothermal driving coupling. The vertical heterojunction could almost completely disinfect 103 CFU/mL E. coli within 30 min under solar light, which was more efficient than the physically mixed composite and pure g-C3N4 and TiO2. The two-dimensional (2D) morphology provides ample surface area in forming the vertical heterojunction and enables intimate contact which is advantageous to charge transfer between g-C3N4 and TiO2. A Z-scheme charge transportation mechanism is confirmed through band structure analysis and reactive species (RSs) probing and trapping experiments. In comparison with physically mixed composite and the single-phase counterparts, the nanocomposite based on Z-scheme electron transfer mode effectively prompts charge pair dissociation and subsequently encourages bacterial inactivation by boosting the generation of RSs. The constructing vertical Z-scheme heterojunction highlights the potential of 2D nanomaterials for accelerated water sterilization.
关键词： photocatalysis,Z-scheme heterojunction,vertical heterojunction,two-dimensional materials,water disinfection
更新于2025-09-23 15:21:21
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Assembly of graphene on Ag3PO4/AgI for effective degradation of carbamazepine under Visible-light irradiation: Mechanism and degradation pathways
摘要： A highly efficient visible-light-driven photocatalyst Ag3PO4/AgI-Graphene (Ag3PO4/AgI-G) was synthesized through a chemical coprecipitation procedure. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) were performed to study the physicochemical structural of the photocatalysts. The photocatalytic activity of the samples was examined by the carbamazepine (CBZ) degradation under artificial visible light and natural sunlight irradiation. Experimental results indicated that the introduction of low mass content of graphene enhanced the photocatalytic performance of Ag3PO4/AgI, and the photocatalytic degradation efficiency of CBZ over Ag3PO4/AgI-3%G (mass ratio of graphene : Ag3PO4/AgI = 3:100) reached 93.06% within 21 min, which was much higher than that over pure Ag3PO4 (26.92%) and Ag3PO4/AgI (74.38%). UV-vis diffuse reflectance spectra, photoluminescence (PL) spectra, transient photocurrent responses and electrochemical impedance spectra (EIS) of the samples were conducted to verify the high photocatalytic performance of the Ag3PO4/AgI-3%G. In addition, possible photocatalytic degradation pathways of CBZ were proposed based on the analysis of transformation products during the reaction. The reactive species trapping experiments and Electron spin resonance (ESR) analysis demonstrated that h+ and ·O2- were the main active oxidant species responsible for CBZ photodegradation. The photocatalytic degradation mechanism of CBZ over Ag3PO4/AgI-3%G under visible light irradiation was schematically proposed. This study not only provides a new technique for the synthesis of Ag3PO4-based photocatalysts with high photocatalytic activity, but also demonstrates that the Ag3PO4/AgI-3%G composite could be a promising photocatalyst for the treatment of waters containing CBZ.
关键词： Photocatalytic degradation,Carbamazepine,Z-scheme,Graphene,Ag3PO4/AgI,Visible light
更新于2025-09-23 15:21:21
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Visible-light degradation of sulfonamides by Z-scheme ZnO/g-C3N4 heterojunctions with amorphous Fe2O3 as electron mediator
摘要： ZnO grafted amorphous Fe2O3 matrix (ZnO/Fe2O3) was coupled with g-C3N4 to synthesize heterojunction photocatalysts with a loosened multilayered structure. The ZnO/Fe2O3/g-C3N4 exhibited enhanced photocatalytic performance in the degradation of sulfamethazine under visible-light irradiation (λ > 420 nm), with an optimum photocatalytic degradation rate approximately 3.0, 2.4 times that of pure g-C3N4 and binary ZnO/g-C3N4. Moreover, the target sulfonamides spiked in actual surface water samples could be efficiently photodegraded by ZnO/Fe2O3/g-C3N4 after 8 h of irradiation, demonstrating its practical potential. An amorphous Fe2O3-mediated Z-scheme mechanism was proposed for the charge transfer at the heterojunction surface, which involved a Fe(III)/Fe(II) oxidation-reduction center that favored the retarded charge recombination and improved photocatalytic activity. Such a mechanism was well supported by the direct detection of surface generated ·O2? and ·OH reactive species. Finally, detailed transformation pathways were proposed based on the photodegradation products identified by QToF-MS analyses. This work provides an illustrative strategy for developing efficient Z-scheme photocatalysts for water purification, by taking advantage of amorphous Fe-based oxides in the semiconductor lattice matching.
关键词： Sulfonamides degradation,Z-scheme mechanism,Electron mediator,ZnO/Fe2O3/g-C3N4,Degradation pathways
更新于2025-09-23 15:21:21
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AIP Conference Proceedings [Author(s) INTERNATIONAL CONFERENCE OF NUMERICAL ANALYSIS AND APPLIED MATHEMATICS (ICNAAM 2017) - Thessaloniki, Greece (25–30 September 2017)] - Additive, multiplicative and iterative splitting methods for Maxwell equations: Algorithms and applications
摘要： We are motivated to optimise splitting methods for Maxwell’s equations. The methods are based on additive, multiplicative and iterative splitting approaches and embed an optimised computation of the Maxwell operators. We decompose Maxwell’s equations into sub-operators and apply the di?erent splitting methods. We obtain numerical bene?ts, while we apply iterative splitting approaches and optimise the computations of the sub-operators. Standard methods, such as additive and multiplicative methods, are more e?ective in fast results, which iterative approaches could reduce iteratively the errors. We present some initial numerical examples for the optimised splitting approaches.
关键词： FDTD scheme,Iterative and exponential splitting
更新于2025-09-23 15:21:21
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[IEEE 2020 7th International Conference on Signal Processing and Integrated Networks (SPIN) - Noida, India (2020.2.27-2020.2.28)] 2020 7th International Conference on Signal Processing and Integrated Networks (SPIN) - Active Power Filter for Harmonic Mitigation of Power Quality Issues in Grid Integrated Photovoltaic Generation System
摘要： Single phase tied with Photovoltaic arrangement (PV) employed on perturbed & observed (P&O) maximum energy point tracking technique with shunt active power filter allied to a rectifier feed R-L nonlinear load. The traditional Perturbed & Observed technique maximum energy point tracking topology is applied to attained maximum output power from Photovoltaic array(PVA), Proportional Integral conventional controller with phase detector (PLL) (PD) phase synchronization are executed to produce reference current. It provide at control unit of pulse width modulation topology( PWM) is utilized in inverter to get steady output voltage. Self supported DC bus PWM converter is regulated from PV array. In proposed architecture is minimized total harmonic pollution existing in supply current owing to power electronic load is (PEL). Total current harmonic pollution (THDi) factor obtain better than compensated using dynamic filter shunt active power filter (SAPF) and power compensation. Hence, reactive power (KVAR) is delivered through system decrease and active power (KW) enhance. The suggested scheme has been implemented by way of MATLAB/SIMULINK 2015(a) environment.
关键词： Pulse width Modulated (PWM) Converter,Proportional Integral controller,Maximum Power Point Tracking (P & O) Scheme,Shunt Active Power Filter (SAPF),Photovoltaic Array (PVA)
更新于2025-09-23 15:21:01