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In situ synthesis of a cadmium sulfide/reduced graphene oxide/bismuth Z-scheme oxyiodide system for enhanced photocatalytic performance in chlorinated paraben degradation
摘要： An efficient reduced graphene oxide (rGO)-based cadmium sulfide/reduced graphene oxide/bismuth oxyiodide (CdS/rGO/BiOI) Z-scheme system was fabricated by an in-situ growth method. Solid interactions between the rGO and nanoparticles promoted the transmission of photoinduced carriers, which separated and accumulated electrons from CdS and holes from BiOI. Moreover, the Z-scheme system enabled CdS electrons to maintain a high reduction capability and BiOI holes to maintain a high oxidation capability. Therefore, the CdS/rGO/BiOI composite exhibited better photocatalytic activity in the degradation of methyl 3,5-dichloro-4-hydroxybenzoate (MDHB) than that of pure CdS and BiOI under visible light irradiation. In particularly, the identification of active species and transformation products revealed that the accumulated photoinduced electrons promoted the reductive dechlorination of MDHB. The dechlorinated byproducts were then oxidatively split and degraded into harmless small-molecule carboxylic acids or inorganic substances by photoinduced holes. This work provided a favorable in situ growth method to design and synthesize Z-scheme photocatalysts for simultaneous chlorinated paraben dechlorination and degradation under visible light irradiation.
关键词： Dechlorination,Visible light photocatalysis,CdS/rGO/BiOI composite,Z-scheme,Chlorinated paraben
更新于2025-09-23 15:21:01
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Reduced Graphene Oxide/TiO2 Nanocomposite: From Synthesis to Characterization for Efficient Visible Light Photocatalytic Applications
摘要： In this study, a green and facile thermal reduction of graphene oxide using an eco-friendly system of D-(+)-glucose and NH4OH for the preparation of reduced graphene oxide was described. The obtained reduced graphene oxide dispersion was characterized by SEM, Dynamic Light Scattering, Raman and X-Ray Photoelectron Spectroscopy. TiO2 nanoparticles and reduced graphene oxide nanocomposites were successively prepared and used in the preparation of heterogeneous photocatalysts that were characterized by Atomic Force Microscopy and Photoluminescence Spectroscopy and subsequently tested as visible light photocatalysts for the photodegradation of Alizarin Red S in water as target pollutant. Obtained results of photocatalytic tests regarding the visible light photocatalytic degradation of Alizarin Red S demonstrated that the use of reduced graphene oxide in combination with TiO2 led to a significant improvement for both adsorption of Alizarin Red S on the catalyst surface and photodegradation efficiencies when compared to those obtained with not doped TiO2.
关键词： visible light photocatalysis,wastewater treatment,reduced graphene oxide,TiO2,glucose-NH4OH
更新于2025-09-19 17:15:36
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Carbonaceous Biomass-Titania composites with Ti–O–C Bonding Bridge for Efficient Photocatalytic Reduction of Cr(VI) Under Narrow Visible Light
摘要： The aim of this study was to develop carbonaceous materials hybridized with anatase TiO2 composed of Activated Carbon-TiO2 (AC-TiO2), Olive Pits-TiO2 (OP-TiO2) and Wood Shaving-TiO2 (WS-TiO2) by ultrasonic-assisted sol-gel process for the photocatalytic Cr(VI) reduction under UV and narrow visible light. The morphology, crystal structure, surface chemistry and optical properties of the as-prepared and bare-TiO2 were investigated by SEM-EDS, XRD, FTIR, BET, UV-DRS, XPS and photo-current measurements. Unlike bare-TiO2, these composite photocatalysts exhibited an enhanced absorption in visible-light. The band gap energies were found to be 3.20 eV, 2.89 eV, 2.81 eV and 2.95 eV for bare-TiO2, AC-TiO2, OP-TiO2 and WS-TiO2, respectively. On the other hand, as-prepared photocatalysts showed significantly improved photocatalytic Cr(VI) reduction performances under UV and visible light illumination compared to bare-TiO2. A total reduction of 10 ppm of Cr(VI) was obtained after 30 min, 50 min and 130 min under visible light (>420) for AC-TiO2, OP-TiO2 and WS-TiO2, respectively at pH: 3 and in the presence of 10 ppm tartaric acid as hole scavenger, while no reduction was detected for bare-TiO2 under visible light (>420). The efficient photocatalytic reduction of Cr(VI) under visible light by AC-TiO2, OP-TiO2 and WS-TiO2 was mainly due to (i): the narrow band gap of TiO2 nanoparticle deposited in carbonaceous materials, (ii): self-photo-sensitizer role of carbonaceous materials via Ti–O–C bonds and (iii): the electron transfer from TiO2 to carbonaceous materials.
关键词： Cr(VI) Reduction,Environmental remediation.,Visible Light,Photocatalysis,Carbonaceous Biomass-TiO2,Band-gap Narrowing
更新于2025-09-19 17:15:36
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CO2-Triggered Reversible Phase Transfer of Graphene Quantum Dots for Visible Light-Promoted Amines Oxidation
摘要： Emerging as novel photoluminescent nanomaterials, carbon dots have attracted increasing attentions in photocatalytic application such as hydrogen evolution, carbon dioxide reduction, pollutants degradation and organic synthesis. However, it is always a cumbersome process to seperate the carbon dots from the reaction system, which may limit their application in photocatalysis. Here, we report a graphene quantum dot with CO2-switchable reversible phase transfer performance via a facile surface functionlization approach. The mechanism of this hydrophilicity and hydrophobicity alteration involves protonation-deprotonation transformation and reversibly formation of hydrophilic bicarbonates salts when bubbling and removal of CO2. Afterwards, the obtained graphene quantum dot is utilized as a visible light photocatalyst for oxidative coupling of amines. Our photocatalyst demonstrates an excellent catalytic efficiency with both high reaction conversion and selectivity being achieved. Furthermore, graphen quantum dot could be recycled via a simple CO2 bubbling method.
关键词： graphene quantum dot,reversible phase transfer,visible light photocatalysis,CO2-switchable,amines oxidation
更新于2025-09-19 17:13:59
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Plasmonic Switching of the Reaction Pathway: Visible‐Light Irradiation Varies the Reactant Concentration at the Solid–Solution Interface of a Gold–Cobalt Catalyst
摘要： Product selectivity of alkyne hydroamination over catalytic Au2Co alloy nanoparticles (NPs) can be made switchable by a light-on/light-off process, yielding imine (cross-coupling product of aniline and alkyne) under visible-light irradiation, but 1,4-diphenylbutadiyne in the dark. The low-flux light irradiation concentrates aniline on the catalyst, accelerating the catalytic cross-coupling by several orders of magnitude even at a very low overall aniline concentrations (1.0 X 10@3 mol L@1). A tentative mechanism is that Au2Co NPs absorb light, generating an intense fringing electromagnetic field and hot electrons. The sharp field-gradient (plasmonic optical force) can selectively enhance adsorption of light-polarizable aniline molecules on the catalyst. The light irradiation thereby alters the aniline/alkyne ratio at the NPs surface, switching product selectivity. This represents a new paradigm to modify a catalysis process by light.
关键词： product selectivity,reaction pathway,selective adsorption,visible-light photocatalysis,plasmonic metal nanoparticles
更新于2025-09-19 17:13:59
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Novel N/Carbon Quantum Dots-Modified MIL-125(Ti) Composite for Enhanced Visible Light Photocatalytic Removal of NO
摘要： A highly efficient and stable photocatalysts were synthesized at room temperature by modifying MIL-125(Ti) with N-doped carbon quantum dots (N/CM(Ti)). The N/CM(Ti) with 2.5 Vol% N doped carbon quantum dots (N/CQDs) had the best light absorption and visible light photocatalytic nitrogen oxide (NO) removal efficiency (approximately 49%). It was found through X-ray photoelectron spectroscopy analysis that the N-Ti-O bond was formed in the 2.5 Vol% N/CM(Ti), which is more conducive to charge transfer. Photocurrent and electrochemical impedance data also showed that the carrier separation efficiency of 2.5 Vol% N/CM(Ti) was significantly superior to that of MIL-125(Ti). In addition, the TiIII-TiIV of MIL-125(Ti) acts as the active center for photocatalytic removal of NO. Two possible electron migration paths were proposed: electron transfer from N/CQDs to TiIII-TiIV center of MIL-125(Ti) due to the photoinduced electron transfer property of N/CQDs, and absorption of UV light generated from the N/CQDs by the terephthalic acid ligand followed by electron transfer to metal active sites for photocatalytic removal of NO.
关键词： MIL-125(Ti),Visible light,Photocatalysis,NO removal,N-doped carbon quantum dots
更新于2025-09-19 17:13:59
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Highly Efficient UV–Visible Photocatalyst from Monolithic 3D Titania/Graphene Quantum Dot Heterostructure Linked by Aminosilane
摘要： As rapidly growing environmental pollution demands the development of efficient photocatalytic materials, tremendous attention has been drawn to TiO2, a widely used photocatalytic material with cost-effectiveness, stability, and outstanding reactivity. To maximize its photocatalytic efficiency by enhancing the photogenerated charge separation, lowering the intrinsically large bandgap (3.2 eV) of TiO2 is a key problem to be overcome. Herein, a new design is reported for an efficient photocatalyst realized by heterostructuring a 3D nanostructured TiO2 monolith (3D TiO2) and graphene quantum dots (GQDs) through using 3-aminopropyltriethoxysilane (APTES) as a linker. The incorporation of APTES between the TiO2/GQD interface enables the formation of a charge injection-type heterostructure, as confirmed by transient absorption spectroscopy, providing improvement of both visible absorption and charge separation. As a result, the heterostructure exhibits a 242% enhanced photocatalytic performance compared to that of nonheterostructured 3D TiO2 under visible irradiation, demonstrating its promising potential for practical photocatalytic applications in environmental remediation.
关键词： TiO2/GQD heterostructure,graphene quantum dots,visible light photocatalysis,charge injection,3D nanostructured TiO2
更新于2025-09-19 17:13:59
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Highly Efficient Cu Induced Photocatalysis for Visible-light Hydrogen Evolution
摘要： Coinage metal (Au, Ag, Cu) induced photocatalysis has emerged as a promising strategy in developing visible-light responsive photocatalysts. Though much progress has been made, yet researchers in this field faced great challenges from both low efficiency and rigorously relying on noble metal Au. In this work, a series of Cu/SrTiO3 with gradually increased Cu particle size from 2.8 to 7.7 nm were successfully prepared with in situ multistep photodeposition method. A highly efficient visible-light photocatalytic H2 evolution is achieved over 0.5 wt% Cu/SiTiO3 with an average Cu particle size of 3.9 nm, which reaches 5 fold as compared with its counterpart Au. As far as we know, it is the first time that Cu induced visible-light photocatalytic water splitting show prominently superior activity than that of Au under the same conditions. Further study reveals that the increase of Cu particle size effectively mitigates Fano interference between interband transition and localized surface plasmon resonance (LSPR), which extends the photo-induced carriers lifetime. The discovery here is supposed to ignite great research interests in exploring efficient and nonprecious Cu induced visible-light photocatalysis.
关键词： Particle size effect,Cu nanoparticles,Visible-light photocatalysis,Fano interference
更新于2025-09-10 09:29:36
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Highly efficient visible-light-assisted photocatalytic hydrogen generation from water splitting catalyzed by Zn0.5Cd0.5S/Ni2P heterostructures
摘要： Development of heterostructured photocatalysts which can facilitate spatial separation of photo-generated charge carriers is crucial for achieving improved photocatalytic H2 production. Consequently, herein, we report the synthesis of Zn0.5Cd0.5S/Ni2P heterojunction photocatalysts with varying amount of Ni2P, 0.5 (S1), 1 (S2), 3 (S3), 5 (S4) and 10wt% (S5) for the efficient visible-light-assisted H2 generation by water splitting. The heterostructures were characterized thoroughly by PXRD, FE-SEM, EDS, HR-TEM and XPS studies. FE-SEM and HR-TEM analyses of the samples unveiled the presence of Zn0.5Cd0.5S microspheres composed of smaller nanocrystals with the surface of the microspheres covered with Ni2P nanosheets and the intimate contact between the Zn0.5Cd0.5S and the Ni2P. Further, visible-light-assisted photocatalytic investigation of the samples showed excellent water splitting activity of the heterostructure, Zn0.5Cd0.5S/1wt%Ni2P (S2) with very high H2 generation rate of 21.19 mmol h?1 g?1 and the AQY of 21.16% at 450 nm with turnover number (TON) and turnover frequency (TOF) of 251,516 and 62,879 h?1 respectively. Interestingly, H2 generation activity of S2 was found to be about four times higher than that of pure Zn0.5Cd0.5S (5.0 mmol h?1 g?1) and about 240 times higher than that of CdS/1wt%Ni2P. The enhanced H2 generation activity of S2 has been attributed to efficient spatial separation of photo-generated charge carriers and the presence of highly reactive Ni2P sites on the surface of Zn0.5Cd0.5S microspheres. A possible mechanism for the enhanced photocatalytic H2 generation activity of Zn0.5Cd0.5S/1wt%Ni2P (S2) has been proposed and is further supported by photoluminescence and photocurrent measurements. Furthermore, the catalyst, S2 can be recycled for several cycles without significant loss of catalytic activity and photostability. Remarkably, the H2 generation activity of S2 was found to be even higher than the reported examples of ZnxCd1-xS doped with noble metal cocatalysts. Hence, the present study highlights the importance of Zn0.5Cd0.5S/Ni2P heterostructures based on non-noble metal co-catalyst for efficient visible-light-driven H2 production from water splitting.
关键词： Heterostructure,Transition metal phosphide,H2 generation,Visible-light photocatalysis,Zn0.5Cd0.5S nanostructures
更新于2025-09-10 09:29:36
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Full-Spectrum Photocatalytic Activity of ZnO/CuO/ZnFe2O4 Nanocomposite as a PhotoFenton-Like Catalyst
摘要： Deriving photocatalysts by the calcination of hydrotalcite-like compounds has attracted growing interest for extending their photocatalytic activity to the visible and even near-infrared (NIR) light regions. Herein, we describe the acquisition of a ZnO/CuO/ZnFe2O4 nanocomposite with good photoFenton-like catalytic activity under UV, visible and near-infrared (NIR) light irradiation by optimizing the calcination temperature of the coprecipitation product of Zn2+, Cu2+ and Fe3+. The ZnO/CuO/ZnFe2O4 nanocomposite is composed of symbiotic crystals of ZnO, CuO and ZnFe2O4, which enable the nanocomposite to show absorption in the UV, visible and NIR light regions and to produce a transient photocurrent in the presence of H2O2 under NIR irradiation. The full-spectrum photoFenton-like catalyst shows improved performance for the degradation of methyl orange with an increasing amount of H2O2 and is very stable in the recycling process. We believe that the ZnO/CuO/ZnFe2O4 nanocomposite is a promising full-spectrum photoFenton-like catalyst for the degradation of organic pollutants.
关键词： ZnO/CuO/ZnFe2O4,photodegradation,Full-spectrum,nanocomposite,photoFenton-like catalyst,near-infrared light,photocatalysis
更新于2025-09-10 09:29:36