查看更多>>摘要：AB2-type(A=rare earth,B=transition metal)intermetallic compounds with C15 structure can easily absorb large amount of hydrogen,showing their potential use as hydrogen storage materials.The crucial problem hindering their application is hydrogen induced amorphization(HIA),which leads to the irreversible hydrogen sorption process.The stability of the AB2 Laves phase compounds,the structural properties,the hydrogenation properties and the controlling factors of HIA are discussed in this review.Comparing with other factors,the atomic radii ratio rA/rB is the most important one influencing the HIA.Multi-element substitution is an efficient way to suppress or limit HIA and may enable AB2 compounds to be suitable for hydrogen storage.
查看更多>>摘要：The photocatalytic decontamination of organic pollutants is an environmentally friendly and efficient water treatment method.The introduction of vacancies,heterojunctions,and doping can enhance the performance of photocatalysts for such applications.In this study,N,O double-vacancy Ce-ZnO/g-C3N4 S-scheme heterojunction photocatalysts were prepared.It is found that the electron separation and transfer efficiencies are considerably improved by the presence of nitrogen vacancies in graphitic carbon nitride(g-C3N4)and oxygen vacancies in ZnO,in addition to the S-scheme heterojunction created be-tween the two materials.In the degradation of methylene blue and ciprofloxacin,the degradation rates exhibited by Ce-ZnO/g-C3N4 are significantly higher than those of the g-C3N4/ZnO system.This remarkable photocatalytic performance of Ce-ZnO/g-C3N4 may result from three key factors:(ⅰ)Ce doping,which produces impurity energy levels;(ⅱ)the generation of electron capture centres by the N and O vacancies;and(ⅲ)the synergistic effect of the S-type heterojunction formed at the interface between the two materials.This study therefore provides new approaches for the use of doping,va-cancies,and heterojunctions to induce the efficient degradation of organic pollutants.
查看更多>>摘要：Reactive oxygen species are essential in photocatalytic water treatment.In this paper,Gd doped carbon nitride(CN)photocatalysts were prepared by simple thermal polymerization for the photocatalytic degradation of tetracycline under visible light irradiation.The photodegradation rate of 1.0GdCN is as high as 95％in 18 min,and the photocatalytic performance is much higher than that of CN.The improvement of photocatalytic performance is mainly attributed to the fact that Gd ion implantation directly provides active sites for oxygen activation and induces the formation of N vacancies.The results of characterizations show that the introduction of Gd in CN can improve the conversion ability of acti-vated oxygen,carrier separation and energy band structure adjustment.Therefore,1.0GdCN photo-catalyst can be employed for efficient photocatalytic synthesis of tetracycline.Furthermore,three ways of photocatalytic degradation of tetracycline were revealed by high performance liquid chromatography-mass spectrometry.This work provides insights into the doping strategy of CN to improve the produc-tion of reactive oxygen species for environmental remediation.
查看更多>>摘要：A novel composite photocatalyst for photocatalytic decomposition of water for hydrogen evolution was successfully synthesized by in-situ growth of nitrogen and sulfur co-doped coal-based carbon quantum dots(NSCQDs)nanoparticles on the surface of sheet cobalt-based metal-organic framework(Co-MOF)and graphitic carbon nitride(g-C3N4,CN).The structure and properties of the obtained catalysts were systematically analyzed.NSCQDs effectively broaden the absorption of Co-MOF and CN in the visible region.The new composite photocatalyst has high hydrogen production activity and the hydrogen production rate reaches 6254 μmol/(g·h)at pH=9.At the same time,NSCQDs synergy Co-MOF/CN composites have good stability.After four cycles of hydrogen production,the performance remains relatively stable.The transient photocurrent response and Nyquist plot experimental results further demonstrate the improvement of carrier separation efficiency in composite catalysts.The semiconductor type(n-type semiconductor)of the single-phase catalyst was determined by the Mott-Schottky test,and the band structure was analyzed.The conductive and valence bands of CN are-0.99 and 1.72 eV,respectively,and the conduction and valence bands of Co-MOF are-1.85 and 1.33 eV,respectively.The mechanism of the photocatalytic reaction can be inferred,that is,Z-type heterojunction is formed be-tween CN and Co-MOF,and NSCQDs was used as cocatalyst.
Mehdi NazeriHossein SedaghatReza RafieiMohammad Amin Farzin...
851-858页
查看更多>>摘要：In this study,we successfully synthesized Er2TiO5@Ag nanocomposites(NCPs)using the ultrasonic-mediated sol-gel technique to create a multifunctional material with enhanced photocatalytic and antibacterial properties.The visible light photocatalytic activities of Er2TiO5 nanoparticles(NPs)and Er2TiO5@Ag NCPs were systematically evaluated under various conditions,including different concen-trations of Basic Blue 41(BB 41)dye and photocatalyst.The results reveal a remarkable improvement in the photocatalytic degradation efficiency of Er2TiO5@Ag NCPs(95％)compared to Er2TiO5 NPs(80％).Furthermore,the antibacterial efficacy of Er2TiO5 NPs and Er2TiO5@Ag NCPs were extensively examined against Gram-positive and Gram-negative bacteria.Notably,Er2TiO5@Ag NCPs exhibit significantly higher minimum bactericidal concentration(MBC)values compared to Er2TiO5 NPs.The antibacterial effect of Er2TiO5@Ag NCPs is particularly pronounced against S.aureus and Pseudomonas aeruginosa,while demonstrating moderate effects on Escherichia coli and Enterococcus faecalis.To assess the biocompatibility of the synthesized materials,we investigated their internalization by MCF-7 cells.Encouragingly,both Er2TiO5 NPs and Er2TiO5@Ag NCPs are found to be effectively internalized by the cells,suggesting their potential application in biomedical fields.Intriguingly,our study unveils the exceptional potential of Er2TiO5@Ag NCPs as a dual-action solution,simultaneously possessing enhanced photocatalytic efficiency and potent antibacterial properties.This multifunctional nanocomposite not only outperforms Er2TiO5 and Ag but also paves the way for innovative applications in sustainable environmental remediation and advanced biomedical technologies,promising a brighter and cleaner future.
查看更多>>摘要：Using the chemical co-precipitation approach,a series of nitrogen(N)and erbium(Er)co-doped ZnO nanoparticles(NPs)was effectively synthesized to enhance the photocatalytic and antibacterial activities.Several characterization techniques,including X-ray diffraction(XRD),X-ray photoelectron spectroscopy(XPS),scanning electron microscopy(SEM),UV-vis,and photoluminescence(PL)spectroscopy,were carried out to validate the evaluated photocatalytic and antibacterial activities.XRD analysis confirms the pure wurtzite ZnO phase without the presence of any secondary phase.XPS analysis confirms the suc-cessful incorporation of nitrogen and erbium into the ZnO matrix.The optical bandgap of ZnO calculated from UV-vis spectroscopy shows a redshift after Er-N co-doping,with the lowest bandgap of 3.215 eV calculated for Zn0.97Er0.03N0.01O0.99 NPs.SEM images demonstrate the formation of nanorods after N-Er co-doping,followed by gradually increased rod diameter and length after N-Er co-doping.Moreover,the photocatalytic activities of ZnO samples were measured by their ability to facilitate the photodegradation of Rhodamine B under UV irradiation.ZnO with 1 mol％N doping exhibits 88％photodegradation of RhB under UV light within 360 min,and the photodegradation and antibacterial activity are greatly improved with Er co-doping.In fact,3 mol％Er-1 mol％N doped ZnO NPs demonstrate the highest photocatalytic activity,with approximately 96％degradation after 360 min,as well as superior antibacterial activity against Staphylococcus aureus(Gram-positive bacteria)and Pseudomonas aeruginosa(Gram-negative bacteria)with the highest zone of inhibition(ZOI)of 16 nm,due to nanorod formation,increased reactive oxygen species(ROS),and decreased electron-hole recombination,as validated by SEM,XPS,and PL spectroscopy.
查看更多>>摘要：Ce-doped WO3 nanoparticles were successfully synthesized by the sol-gel method and characterized through advanced characterization techniques.The high resolution transmission electron microscopy(HRTEM)and scanning electron microscopy(SEM)results show a reduction in the agglomeration of nanoparticles upon doping.The energy dispersive X-ray(EDX)analysis validates the existence of the Ce element in all the doped samples.X-ray photoelectron spectroscopy(XPS)and Raman spectra justify the presence of structural defects(oxygen vacancies)and successful formation of the monoclinic WO3 phase,respectively.The Kubelka-Munk function indicates a decrease in band gap with doping,while photo-luminescence(PL)spectra show intense visible and UV emissions.Significantly,all doped samples exhibit higher photocatalytic performance than pure WO3 nanoparticles,with the 6 wt％Ce-doped sample displaying the highest degradation rate.Doping with Ce can help to increase the surface area of WO3,thereby improving its photoactivity.Moreover,a correlation between PL and photocatalysis is established in the light of oxygen vacancies suggesting a direct dependence of high photocatalytic activity on strong PL signals of WO3 nanostructures.Trapping experiments further reveal that the degradation process is primarily driven by active species,providing insight into a plausible photocatalytic mechanism.
查看更多>>摘要：Construction of heterojunctions is a normal and effective strategy to improve the photocatalytic per-formances of semiconductors,through which both the lifetime and the redox ability of electrons/holes can be improved,as compared to the respective component.On this basis,we constructed Z-scheme CdS/LaFeO3 heterojunctions(CdS/LFO),by in-situ growing different amounts of CdS on the surface of LaFeO3,for photocatalytic degradation of tetracycline hydrochloride(TC)in aqueous solution at room temper-ature.The crystal structure,surface morphology and optoelectronic properties of the CdS/LFO hetero-junctions were systemically characterized to correlate the reaction activity.Photocatalytic tests indicate that the CdS/LFO heterojunctions exhibit promising activity for TC degradation under visible light irra-diation(λ≥ 420 nm),with 85％TC conversion obtained at reaction time of 45 min,which is 3.4 and 1.9 times higher than that of CdS and LaFeO3.The CdS/LFO heterojunctions are also stable in the reaction and can be reused for four cycles with no appreciable activity loss.The applicability of CdS/LFO to photo-catalytic degradation of organic dyes,as well as the reaction mechanism,was also explored.
查看更多>>摘要：The CeO2-TiO2@MnOx catalyst was prepared by the co-precipitation method and applied to the photo-thermocatalysis system of ethyl acetate and NO simultaneous degradation under H2O at low tempera-ture,which introduced Ce into TiO2@MnOx hollow sphere structure.The optimum TiO2/MnOx ratio and Ce introducing amount were obtained in the process.Among of them,the NO and ethyl acetate con-version percentage of TiO2@MnOx(nMn:nTi=40:40)is 74％and 62％at 240 ℃,respectively.CeO2-TiO2@MnOx(nMn-Ti;nce=1:1)exhibits the best catalytic performance,its efficiency for NO conversion is 83％and the conversion of ethyl acetate reaches 72％at 240 ℃.In addition,it is confirmed that the Ce-doped nanocomposites have more uniform dispersion through various characterization and analysis methods.Meanwhile,these catalysts have a large specific surface area as well as a large number of surface-active oxygen and oxygen vacancies.It can further improve the catalytic performance based on the adjusted ratio of active components.Moreover,this work investigated the relationship between multi-metal interactions and catalytic performance in the presence of H2O.Finally,the possible reaction pathways for the simultaneous removal of NO and ethyl acetate were explored in our system.
查看更多>>摘要：The direct activation of methane under mild condition to achieve highly selective of oxygenates is a challenging project.In this study,a well dispersed silver supported ZnTiO3 catalyst was prepared to achieve selective preparation of methanol from methane and water under mild condition.X-ray diffraction,transmission electron microscopy and X-ray photoelectron spectroscopy characterizations demonstrate that silver species are uniformly dispersed on ZnTiO3 surface in the form of metallic silver nanoparticles.The photoelectric characterizations reveal that the addition of silver species enhances light absorption and promotes charge separation of the catalysts.Under the reaction conditions of 50 ℃ and 3 MPa,the methanol is obtained as the only liquid product over the designed Ag/ZnTiO3 catalyst under light irradiation.In this photocatalytic process,the holes generated by ZnTiO3 activate water to produce intermediate OH,which further reacts with methane to synthesize methanol.The silver species as co-catalysts extend the light absorption range of ZnTiO3 as well as promote charge separation.
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