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Effect of conduction band potential on cocatalyst-free plasmonic H <sub/>2</sub> evolution over Au loaded on Sr <sup>2+</sup> -doped CeO <sub/>2</sub>
摘要： There is little information on the effect of the conduction band (CB) position on plasmonic hydrogen (H2) formation under visible light irradiation over gold (Au) nanoparticles supported on semiconductors because there were no appropriate materials for which the CB position gradually changes. In this study, we analyzed the flatband potential of strontium ion (Sr2+)-doped cerium(IV) oxide (CeO2:Sr) and found that the CB position gradually shifted negatively from +0.031 V to ?1.49 V vs. NHE with an increase in the Sr2+ mole fraction. Plasmonic photocatalysts consisting of Au nanoparticles, CeO2:Sr and a platinum (Pt) cocatalyst were prepared and characterized by using X-ray diffraction, UV-vis spectroscopy, and transmission electron spectroscopy. Photocatalytic reaction under visible light irradiation revealed that H2 was produced over Au nanoparticles supported on CeO2:Sr having the CB potential of ?0.61 V vs. NHE and that the negative limit of the CB position for electron injection from Au nanoparticles existed between ?0.61 V and ?1.49 V vs. NHE. We found that Au/CeO2:Sr plasmonic photocatalysts also produced H2 without the aid of a Pt cocatalyst due to the sufficiently negative potential of electrons injected into the CB of CeO2:Sr.
关键词： hydrogen evolution,visible light irradiation,gold nanoparticles,plasmonic photocatalysts,strontium-doped cerium oxide
更新于2025-11-19 16:51:07
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Enhanced UV and visible light - driven Photocatalytic degradation of Tartrazine by Nickel-doped Cerium oxide Nanoparticles
摘要： Nickel-doped cerium oxide nanoparticles were synthesized via a simple aqueous coprecipitation method. The synthesized nanoparticles were thoroughly characterized by PXRD, TEM, SEM, EDX, Raman, and UV-Vis spectroscopic techniques. XRD study confirmed the doping of nickel in the cerium oxide lattice. The shift in Raman spectra revealed the formation of nanoparticles in their pure phase with fluorite structure. EDX revealed the formation of a solid solution on doping Ni- to CeO2. SEM images revealed considerable agglomeration. TEM analysis asserted the average particle size of 8-10 nm with a well-defined spherical shape. The particle size was found to be sensitive to dopant concentration, i.e., it decreased with increase in the concentration of the dopant. A comparative UV-visible spectroscopic analysis showed the remarkable red shift in the band gap of nickel-doped cerium oxide nanoparticles. Investigation of photocatalytic activity towards degradation of azo dye tartrazine showed that 3 mol% and 5 mol% Ni- CeO2 nanoparticles exhibited 53.4% and 63.7% photodegradation respectively under visible irradiation while 57.4% and 65.4% respectively under UV irradiation. The study suggests that the band gap of cerium oxide nanoparticles can be easily tuned (decreased) by doping of nickel at different concentrations. The observed improved photocatalytic activity upon Nickel doping is attributed to the narrow band gap.
关键词： azo dye,mechanism,tartrazine,photocatalysis,Nickel-doped cerium oxide nanoparticles
更新于2025-09-23 15:21:01
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Effect of Strontium Doping on the Band Gap of $$\hbox {CeO}_{2}$$ CeO 2 Nanoparticles Synthesized Using Facile Co-precipitation
摘要： Pure, 3 mol% and 5 mol% Sr-doped cerium oxide nanoparticles were synthesized by facile aqueous co-precipitation method using cerium nitrate hexahydrate and strontium chloride hexahydrate as the precursors without using any capping agent. The synthesized material was characterized by XRD, SEM, EDX, TEM, Raman spectroscopy and UV–Vis spectroscopic techniques. SEM analysis showed agglomeration of the particles. The Debye–Scherrer analysis revealed ?uorite structure of the synthesized material with crystallite size in 6–10 nm range. TEM con?rmed the spherical morphology of the particles and particle size distribution in the range of 5–8 nm. UV–Vis spectroscopic study revealed that Sr-doping led to increase in the band gap from 3.2 to 3.7 eV and shifting of absorption edge to the lower wavelength. The blue shift in the band gap with the dopant concentration shows that the band gap of doped cerium oxide nanoparticles can be tuned with variation in the dopant concentration.
关键词： Sr-doped cerium oxide,Blue shift,Band gap
更新于2025-09-19 17:15:36
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Systematic enumeration and proficient chemical sensing applications of Eu3+@CeO2 nanocrystals
摘要： Current study displayed the application of hydrothermal method for the preparation of highly crystalline nanocrystals of Eu3+ doped cerium oxide (Eu@CeO2) particles. The influence of doping percentage and annealing effects were studied on the crystalline nature and morphology of particles. The size, optical properties and lattice parameters were calculated as a function of dopant concentrations and their discrepancies were explained in detail. Integration of Eu3+ ions on CeO2 could unlock a new trail to optimize the photoluminescence properties of formed nanocrystals. The generated oxygen vacancies (Vo··) have the ability to affect the characteristic features of cerium oxide in solid state. The variations in the nature of surface defect in presence of Eu3+ ions with CeO2 nanoparticles were explained with the results of XPS studies. The obtained results validated that defect-induced band gap modification by Eu3+ ion doping on CeO2 could be employed as effective chemical sensor for harmful metal ions in real water samples.
关键词： photoluminescence,lattice parameter,crystalline,doped Cerium oxide,oxygen vacancies,hydrothermal
更新于2025-09-11 14:15:04