研究目的
To investigate the photocatalytic abatement of acetic acid in liquid phase and propene in gas phase using TiO2 modified with transition metallic species (Cr, Co, Ni, and Cu).
研究成果
The modification of P25 TiO2 with transition metals (Cr, Co, Ni, Cu) via impregnation and heat treatment in argon enhances photocatalytic activity, with performance dependent on the metal's electrochemical properties. Cu/P25 showed the highest activity due to effective electron trapping and transfer. In liquid phase, all metal-modified catalysts outperformed bare P25 for acetic acid decomposition, while in gas phase, bare P25 was more active for propene oxidation, attributed to differences in rate-determining steps between media. The study highlights the potential of non-noble metal-doped TiO2 for environmental remediation, with recommendations for optimizing metal selection and reaction conditions for practical applications.
研究不足
The study is limited to specific transition metals (Cr, Co, Ni, Cu) and a fixed metal loading of 1 wt.%. The reactions were conducted under controlled laboratory conditions with UV light (365 nm), which may not fully represent solar or real-world conditions. The low conversion rates (e.g., acetic acid conversion up to 0.13%) indicate potential inefficiencies. Differences in activity between gas and liquid phases suggest media-specific limitations, such as diffusion effects in liquid phase and surface coverage in gas phase.
1：Experimental Design and Method Selection:
The study involved modifying commercial P25 TiO2 with transition metals (Cr, Co, Ni, Cu) via impregnation using aqueous nitrate solutions, followed by heat treatment in argon at 500°C to decompose nitrates and enhance metal-TiO2 interaction. Photocatalytic activity was tested in liquid phase (acetic acid decomposition) and gas phase (propene oxidation) under 365 nm irradiation.
2：Sample Selection and Data Sources:
Samples included bare P25-Ar and M/P25-Ar (M = Cr, Co, Ni, Cu) with 1 wt.% metal loading. Characterization data were obtained from N2 adsorption, SEM, XRD, UV-vis DRS, and XPS analyses.
3：List of Experimental Equipment and Materials:
Equipment included Quantachrome Autosorb-6B for N2 adsorption, JSM-840 JEOL SEM, Hitachi S3000N SEM-EDX, SEIFERT 2002 XRD, Jasco V-670 UV-vis spectrophotometer, K-Alpha XPS spectrophotometer, quartz reactors (Heraeus and AFORA), mercury vapor lamps (TQ-150 and Philips UV-A), mass spectrometers (Balzers Thermostar GSD 301 01), and materials like P25 TiO2, metal nitrates, acetic acid, propene, helium, and air.
4：Experimental Procedures and Operational Workflow:
For acetic acid decomposition, a 1 M solution with catalyst was irradiated for 12 h with He bubbling; gas products analyzed by MS. For propene oxidation, catalyst was placed in a reactor, fed with propene in air, irradiated until stationary, and outlet gas analyzed by MS.
5：Data Analysis Methods:
Data analyzed using BET and Dubinin-Radushkevich equations for surface area, Scherrer's equation for crystal size, Kubelka-Munk function for band gap, and XPS peak fitting with Gaussian functions.
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