研究目的
To investigate the role of the photocatalytic composite material CeO2/TiO2 interface on the photocatalytic degradation of organic compounds under visible and UV light, specifically focusing on the effects of morphology, adsorption capacity, and reactive oxygen species.
研究成果
The hydrothermal method successfully modified TiO2 morphology, increasing surface area and adsorption capacity, particularly for MB. Ce doping enhanced thermal stability but did not significantly reduce band gap or improve PVP degradation due to lack of adsorption. MB degradation was primarily through dye-sensitized photocatalysis involving singlet oxygen, as evidenced by scavenger studies. The local morphology and interface contact between CeO2 and TiO2 were more critical than Ce content for photocatalytic performance.
研究不足
The study is limited to specific organic compounds (PVP and MB) and may not generalize to other pollutants. The low Ce content made detection challenging with XPS, and residual sodium from synthesis could affect results. The hydrothermal method's effectiveness depends on agitation and temperature control, potentially introducing variability. The focus on aqueous suspensions may not apply to other media.
1：Experimental Design and Method Selection:
The study used a hydrothermal method to prepare Ce-doped TiO2 photocatalysts with varying cerium content (0%,
2：09%, 29%, 57% mol) and calcination temperatures (450°C or 600°C). Photocatalytic activity was evaluated using methylene blue (MB) and polyvinylpyrrolidone (PVP) as test compounds in a slurry reactor under visible or UV light irradiation. Sample Selection and Data Sources:
TiO2 P25 (Degussa Co.) was used as the base material, with Ce(NO3)3 (Sigma Aldrich) for doping. Distilled water and analytical grade chemicals were employed.
3：List of Experimental Equipment and Materials:
Equipment included a jacketed annular photoreactor, visible light lamp (400-800 nm), medium-pressure mercury vapor lamp (HQL E27 OSRAM, 41 W m?2), magnetic stirrer, autoclave, oven, filtration setup, TOC analyzer (Shimadzu TOC-VCPH), UV–vis spectrophotometer (HACH DR5000), XRD (Philips X'Pert), TEM (JEM-2100), BET surface area analyzer (Quantachrome Autosorb-1), UV–vis diffuse reflectance spectrophotometer (Perkin Elmer UV/vis/NIR Lambda 750), zeta potential analyzer (Stabino1 Particle Charge Mapping), and XPS (VG ESCA 3000). Materials included NaOH, HCl, L-Histidine, sodium azide, DMSO, sodium carbonate as scavengers.
4：0). Materials included NaOH, HCl, L-Histidine, sodium azide, DMSO, sodium carbonate as scavengers. Experimental Procedures and Operational Workflow:
4. Experimental Procedures and Operational Workflow: Photocatalysts were prepared by hydrothermal treatment of TiO2 P25 with NaOH and Ce(NO3)3 at 120°C for 24 h, followed by washing, drying, and calcination. Adsorption equilibrium was reached in dark conditions before photocatalytic tests. Reactions were conducted with air bubbling and stirring, with samples collected at intervals for TOC and absorbance measurements. Scavenger studies used 5 mM concentrations.
5：Data Analysis Methods:
Pseudo-first-order kinetics were applied for degradation rates. BET surface area, band gap (via Kubelka-Munk equation), crystallite size (Scherrer equation), and zeta potential were measured. XPS and XRD were used for chemical and structural analysis.
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Transmission electron microscope
JEM-2100
JEOL
Morphology and particle size analysis
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UV–vis spectrophotometer
Lambda 750
Perkin Elmer
Band gap measurement
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TOC analyzer
TOC-VCPH
Shimadzu
Total organic carbon measurement
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TiO2 P25
P25
Degussa Co.
Base material for photocatalyst preparation
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Ce(NO3)3
Sigma Aldrich
Source of cerium for doping
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X-ray diffractometer
X'Pert
Philips
Characterization of crystalline properties
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BET surface area analyzer
Autosorb-1
Quantachrome
Surface area measurement
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Zeta potential analyzer
Stabino1 Particle Charge Mapping
Particle Metrix
Zeta potential measurement
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XPS system
ESCA 3000
VG
Surface analysis and valence state determination
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UV–vis spectrophotometer
DR5000
HACH
Absorbance measurement for decolorization
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Visible light lamp
Light source for photocatalytic reactions
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Medium-pressure mercury vapor lamp
HQL E27
OSRAM
UV light source for photocatalytic reactions
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