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Photocatalytic Reforming of Sugar and Glucose into H2 over Functionalized Graphene Dots
摘要： Photocatalytic reforming of biomass into H2 combining with its photosynthesis counterpart constitutes a sustainable carbon cycle that produces a clean solar fuel. This study reports the use of environmentally benign graphene-based photocatalysts to effectively reform sugar and glucose. We produce a catalyst consisting of sulfur and nitrogen codoped graphene oxide dots (SNGODs) by sequentially annealing graphite-derived graphene oxide with sulfur and ammonia, exfoliating the annealed product into dots, and autoclaving the dots in an ammonia solution. The codoping introduces quaternary nitrogen on the graphene basal plane to patch the vacancy defects and the autoclaving creates a conjugation between the nitrogen nonbonding states and the graphitic-π orbital by introducing peripheral amide and amino groups. These functionalization steps enlarge the electron resonance domain, narrowing the bandgap and inducing charge delocalization and separation. Here, when SNGODs deposited with a Pt cocatalyst effectively catalyzed H2 production from aqueous solutions of sugar and glucose under visible light irradiation for more than 80 h. The apparent quantum yields of the reforming of sugar and glucose reach 11% and 7.4%, respectively, under 420-nm monochromatic irradiation. This pioneer study demonstrates the superiority of using carbon-based photocatalysts for biomass reforming and provides a structure-tuning strategy for enhancing the catalytic activity.
关键词： Reforming of sugar,Hydrogen production,Graphene oxide,Reforming of glucose,Photocatalytic reforming
更新于2025-11-20 15:33:11
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Solvent-exfoliation of transition-metal dichalcogenide MoS2 to provide more active sites for enhancing photocatalytic performance of BiOIO3/g-C3N4 photocatalyst
摘要： The ternary complex photocatalysts of BiOIO3/g-C3N4/MoS2 by solvent-exfoliation method was synthesized for the first time. In the typical procedure, the BiOIO3/g-C3N4 was obtained via hydrothermal synthesis technique, and then the BiOIO3/g-C3N4/MoS2 photocatalysts were prepared via ultrasonic solvent-exfoliation method from bulk commercial MoS2 in the alcohol solution. The samples of BiOIO3/g-C3N4/MoS2 were analyzed by PL, XRD and other characterization analysis methods. The photocatalytic activity of the as-prepared samples was investigated by removing gas phase mercury irradiation under visible light. The as-prepared BCM-0.3 exhibits excellent photocatalytic performance, being with the highest efficiency of 70.58%. Owing to the electronic channels of field-effect, an internal electric field was formed through the corresponding band-gap engineering, improving photocatalytic reaction. Besides, the excellent activity of the ternary photocatalysts BiOIO3/g-C3N4/MoS2 is attributed to heterostructure between BiOIO3/g-C3N4 and MoS2, which enlarges spectral response and improved separation efficiency of charge carriers, and MoS2-composing, which provides more active sites for catalytic oxidation. In addition, the as-prepared samples with excellent photocatalytic performance also offer a perspective insight into the hydrogen evolution, CO2 conversion and degradation of organic pollutants.
关键词： Photocatalytic,Solvent-exfoliation,Heterostructure,Oxidation,Field-effect
更新于2025-11-20 15:33:11
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Valorization of tire wastes to carbon quantum dots (P-CDs) and photocatalytic degradation enhancement of organic wastes using ZnO-CDs nanocomposites
摘要： Valorization of solid wastes for the production of valuable materials is of great importance for sustainable development. In this paper, removal for solid and liquid wastes via hydrothermal and catalytic degradation was reported. The first removal process is the hydrothermal conversion of solid waste, here solid wastes of tire, to phosphorous and nitrogen doped carbon nanodots (P-CDs). The second removal is the visible-NIR light driven photocatalytic degradation of liquid waste, here methylene blue (MB) solution, using P-CDs loaded on ZnO nanoparticles. Energy-efficient light emitting diode (LED) was used as a weak sufficient irradiation source. Photodegradation rate constants for ZnO-P-CDs were almost 10 times higher (0.08 h?1 for ZnO-P-CDs) comparing to pure ZnO (0.008 h?1), such enhancement is significant for a weak light source. Cyclic voltammetry and optical properties were used to find HOMO and LUMO of P-CDs. Based on the energy levels of ZnO and P-CDs, the catalytic enhancement was attributed to increasing the separation rate of photogenerated electrons and hole due to the transfer of electrons from the conduction bands of P-CDs to the conduction band of ZnO. Up-conversion photoluminescence of P-CDs is another reason for increasing the separation of excitons and harvesting the longer wavelength light. The proposed approach, solid and liquid waste removal via hydrothermal and catalytic degradation combined with weak LED light, would be a powerful approach in solid waste treatment and water purification technology, simultaneously.
关键词： Valorization,Tire wastes,Carbon quantum dots,Photocatalytic degradation,ZnO-P-CDs nanocomposites
更新于2025-11-19 16:56:42
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TiO2/SnO2 and SnO2/TiO2 heterostructures as photocatalysts for degradation of stearic acid and methylene blue under UV irradiation
摘要： The effect TiO2/SnO2 (TiO2 is on the top and SnO2 at the bottom) and SnO2/TiO2 (SnO2 is on the top and TiO2 at the bottom) heterostructures towards photocatalytic degradation of stearic acid and methylene blue is reported. The two heterostructures, wherein SnO2 (or TiO2) is the top or bottom layer, are prepared by the sol-gel technique. TiO2/SnO2 film exhibit better photocatalytic activity as compared to SnO2/TiO2, TiO2 and SnO2 films. Wettability studies reveal that TiO2/SnO2 films modified with stearic acid (8mM concentration of stearic acid in ethyl alcohol) tend towards superhydrophobic regime with contact angle as high as 137o. Further, TiO2/SnO2 films are efficient in degrading the stearic acid under UV irradiation. Interestingly, TiO2/SnO2 films that display flake like structures, with increased charge separation, are responsible for better degradation of pollutants under UV irradiation because of coupling heterostructures.
关键词： Bilayer film,Wettability,Superhydrophobic,Photocatalytic activity
更新于2025-11-19 16:56:35
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Synthesis, Crystal Structure, and Photocatalytic Properties of a Zinc(II) Coordination Polymer Based on 3-Hydroxy-2-pyridinecarboxylic Acid
摘要： The zinc(II) compound, [Zn3(HL)6]n (1) (H2L = 3-hydroxypyridine-2-carboxylic acid) was synthesized by a solvothermal reaction of Zn(NO3)2·6H2O and 3-hydroxypyridine-2-carboxylic acid as raw materials. The structure of complex 1 was determined by single-crystal X-ray diffraction analysis and further characterized by elemental analysis, Fourier transform infrared spectroscopy, thermogravimetric analysis, as well as powder X-ray diffraction. X-ray structure analysis demonstrates that the complex crystallizes in the monoclinic system, space group P21/n. There are three zinc ions in the asymmetric unit, which are either five-coordinate or six-coordinate. The asymmetric units are further bridged by the carboxylate of the organic ligands, featuring a 2D framework. The solid state diffuse-reflectance UV/Vis spectra reveals that complex 1 has semiconducting nature with the energy bandgap (Eg) estimated to be 3.11 eV. The photocatalytic properties of complex 1 in degradation of organic dyes were further investigated. Results showed that the complex could degrade 54 % of the dye methylene blue solution within 120 min under UV irradiation light and reused for five times without the decline of the photocatalytic activity.
关键词： Crystal structure,Photocatalytic properties,Zinc,3-Hydroxypyridine-2-carboxylic acid,Solvothermal reaction,Coordination polymer
更新于2025-11-19 16:56:35
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Dual functionality of K0.3WO3/Ag2O nanocomposites for smart window: Energy saving and visible photocatalytic self-cleaning performance
摘要： Series of novel K0.3WO3/Ag2O nanocomposites were successfully prepared by simple two steps method. An exciting fact that near-infrared light shielding and visible photocatalytic self-cleaning effects are integrated into the K0.3WO3/Ag2O film (weight ratio of K0.3WO3 to Ag2O = 30) could offer significant potential applications in smart windows. Furthermore, the optical properties and photocatalytic activity of the composites could be tuned by adjusting the weight ratio of K0.3WO3 to Ag2O. The obtained K0.3WO3/Ag2O films presented enhanced photocatalytic self-cleaning performance compared with pure K0.3WO3 under visible light irradiation. The improved self-cleaning performance of the K0.3WO3/Ag2O composites was ascribed to a combined contribution of the matched energy band structures and boosted separation efficiency of photo-generated carriers. An approximately 2.3°C-3.4 °C decrease in inner temperature was obtained for the heat box covered with K0.3WO3/Ag2O coated glass. Therefore, the proposed K0.3WO3/Ag2O (weight ratio of K0.3WO3 to Ag2O = 30) smart coating is a promising material for self-cleaning energy-saving windows.
关键词： Self-cleaning,Visible photocatalytic,Ag2O,KxWO3,Tungsten bronze,NIR shielding
更新于2025-11-19 16:56:35
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An anti-symmetric dual (ASD) Z-scheme photocatalytic system: (ZnIn2S4/Er3+:Y3Al5O12@ZnTiO3/CaIn2S4) for organic pollutants degradation with simultaneous hydrogen evolution
摘要： An anti-symmetric dual (ASD) Z-scheme ZnIn2S4/Er3+:Y3Al5O12@ZnTiO3/CaIn2S4 photocatalyst was prepared by isoelectric point and calcination methods. The photocatalytic activity is estimated via degradation of Acid Orange II as a target organic contaminant with simultaneous hydrogen evolution under simulated solar-light irradiation. The prepared ASD Z-scheme ZnIn2S4/Er3+:Y3Al5O12@ZnTiO3/CaIn2S4 photocatalyst has a high photocatalytic activity, which can be assigned to the enlarged photoresponse range, increased reduction surface and enhanced separation efficiency of photo-induced carriers. Furthermore, the cyclic experiment proves that the prepared ASD Z-scheme ZnIn2S4/Er3+:Y3Al5O12@ZnTiO3/CaIn2S4 photocatalyst still maintains a high photocatalytic activity within five repetitive cycles. Moreover, the mechanism on photocatalytic degradation of organic pollutants with simultaneous hydrogen evolution caused by ASD Z-scheme ZnIn2S4/Er3+:Y3Al5O12@ZnTiO3/CaIn2S4 photocatalyst is proposed. It is wished that this study could provide a promising pathway for effective degradation and rapid hydrogen production.
关键词： Simultaneous hydrogen evolution,Organic contaminants,Anti-symmetric dual (ASD) Z-scheme photocatalytic system,ZnIn2S4/Er3+:Y3Al5O12@ZnTiO3/CaIn2S4 composite,Up-conversion luminescence agent,Photocatalytic degradation
更新于2025-11-19 16:51:07
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A novel photocatalyst, Y2SiO5:Pr3+,Li/Pt-NaNbxTa1?xO3, for highly efficient photocatalytic hydrogen evolution under visible-light irradiation
摘要： In this work, Y2SiO5:Pr3+,Li, as an excellent up-conversion luminescence agent from visible-light to ultraviolet-light, is synthesized by using sol-gel method. And then, a series of Y2SiO5:Pr3+,Li/NaNbxTa1?xO3 (x = 0.00, 0.25 and 0.50) with different amounts of Y2SiO5:Pr3+,Li are prepared by using hydrothermal method. The prepared samples are characterized by X-ray diffractometer (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), UV–vis absorption spectroscopy and photoluminescence spectroscopy (PL). The activities of Y2SiO5:Pr3+,Li/Pt-NaNbxTa1?xO3 are investigated through photocatalytic hydrogen evolution in 10 vol% methanol solution under visible-light irradiation. The influences of Nb content in NaNbxTa1?xO3, mass ratio of Y2SiO5:Pr3+,Li and NaNb0.5Ta0.5O3, visible-light irradiation time and reuse-times are examined on the visible-light photocatalytic hydrogen evolution. The experimental results showed that the prepared Y2SiO5:Pr3+,Li/Pt-NaNb0.5Ta0.5O3 with 0.4:1.0 mass ratio of Y2SiO5:Pr3+,Li and NaNb0.5Ta0.5O3 and 0.25 wt% Pt loading displayed a highest evolved hydrogen activity under visible-light irradiation. This study may provide some significant references for large scale photocatalytic hydrogen evolution utilizing solar energy.
关键词： Visible-light photocatalyst (Y2SiO5:Pr3+,Li/Pt-NaNb0.5Ta0.5O3),Photocatalytic hydrogen evolution,Pt loading,Nb-substituted NaTaO3,Up-conversion luminescence agent (Y2SiO5:Pr3+,Li)
更新于2025-11-19 16:51:07
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Self-generating CeVO4 as conductive channel within CeO2/CeVO4/V2O5 to induce Z-scheme-charge-transfer driven photocatalytic degradation coupled with hydrogen production
摘要： The construction of highly efficient Z-scheme photocatalytic system is regarded as a hot research topic in the fields of environmental remediation and renewable energy production. In this work, a novel Z-scheme CeO2/CeVO4/V2O5 photocatalyst is successfully prepared by using solid phase reaction method. The photocatalytic degradation of organic pollutant (Methylene Blue) with simultaneous hydrogen production is efficiently realized over the prepared Z-scheme CeO2/CeVO4/V2O5 photocatalysts under visible-light irradiation. The effects of treatment temperatures and treatment times of CeO2/V2O5 composite on the photocatalytic performance of Z-scheme CeO2/CeVO4/V2O5 photocatalyst are studied. The as-prepared Z-scheme CeO2/CeVO4/V2O5 (550-3) photocatalyst heat-treated at 550 °C for 3.0 h exhibits the highest photocatalytic performance. It can be ascribed to a moderate amount of CeVO4 nanoparticles generated between CeO2 and V2O5. The generated CeVO4 nanoparticles can be used as effective conductive channel to transfer the photo-generated carriers. At the same time, as redox reaction centers it can further accelerate the transfer of photo-generated electrons, effectively enhancing the separation efficiency of photo-generated electron and hole pairs. Furthermore, cyclic test demonstrates that the as-prepared Z-scheme CeO2/CeVO4/V2O5 (550-3) photocatalyst still maintains a high level of photocatalytic activity within five periods under the same conditions. Moreover, the related photocatalytic mechanism for degradation of organic pollutants with simultaneous hydrogen evolution over the Z-scheme CeO2/CeVO4/V2O5 (550-3) photocatalyst is proposed. Perhaps, this study affords a simple and novel method to design and develop next generation of highly efficient Z-scheme photocatalysts.
关键词： Conductive channel,Z-scheme CeO2/CeVO4/V2O5 photocatalyst,Solid phase reaction method,Simultaneous hydrogen evolution,Visible-light photocatalytic degradation
更新于2025-11-19 16:51:07
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Particle size effects of tetrahedron-shaped Ag3PO4 photocatalyst on water-oxidation activity and carrier recombination dynamics
摘要： We investigated photocatalytic water-oxidation performance of tetrahedron-shaped silver phosphate (Ag3PO4) crystals with various particle sizes. The performance was clearly influenced by the particle size. The maximum activity was found for the particle with a tetrahedron edge with 1.5 μm length, which showed the highest rate of oxygen evolution. A series of analysis against time-resolved diffuse reflection spectra of the powder samples reveals that not only carrier recombination dynamic but also photoexcited carrier density can play important roles in the water oxidation. Our finding should contribute to give one of the basic ideas when designing semiconductor photocatalysts for water splitting.
关键词： Silver phosphate,Photocatalytic water oxidation,Global analysis,Carrier dynamics
更新于2025-11-19 16:51:07