研究目的
To conduct a comparative investigation of particle- and thin films-based photocatalysts using three different oxynitride materials for photoelectrochemical solar water splitting.
研究成果
Particle-based photoanodes show higher absolute photocurrent densities due to larger surface area and better light absorption, but thin films offer advantages in charge carrier separation and mobility due to better morphological features. Normalizing for surface area and absorbance, thin films perform comparably or better. Thin films serve as ideal model systems for fundamental studies due to well-defined surfaces and controlled properties. Future work should explore combining both approaches, such as growing films on 3D nanostructures.
研究不足
The study uses bare semiconductors without co-catalysts, which may limit performance compared to optimized systems. Thin films have lower surface area and absorbance than particles, affecting absolute photocurrent. Chemical compositions of thin films deviate from ideal stoichiometry, potentially influencing properties. The comparison is based on specific synthesis methods (EPD for particles, PRCLA for films), and results may vary with other techniques.
1：Experimental Design and Method Selection:
The study compares particle-based and thin film-based photoanodes made from LaTiOxNy, BaTaOxNy, and CaNbOxNy oxynitrides. Particle-based photoanodes were prepared by electrophoretic deposition (EPD) of powders synthesized via thermal ammonolysis of precursor oxides. Thin films were deposited using pulsed reactive-crossed beam laser ablation (PRCLA) on TiN-buffered MgO substrates. Photoelectrochemical (PEC) measurements were performed in a three-electrode configuration to assess photoactivity.
2：Sample Selection and Data Sources:
Oxynitride powders were synthesized from precursor oxides (La2Ti2O7, Ba5Ta4O15, Ca2Nb2O7) using solid-state reactions and ammonolysis. Thin films were grown on (001)-oriented MgO substrates with TiN buffer layers.
3：List of Experimental Equipment and Materials:
Equipment includes X-ray diffractometer (Bruker-Siemens D500), SEM (Zeiss Supra VP55), UV-Vis spectrophotometer (Cary 500 Scan), BET surface area analyzer (Quantachrome Nova 2200), RBS and ERDA setups, KrF excimer laser for PLD and PRCLA, electrochemical interface (Solartron 1286), Xe arc lamp (Newport 66477), photodetector (Gentec-EO), and profilometer (Veeco Dektak 8). Materials include FTO substrates, TaCl5, NH3 gas, NaOH electrolyte, and various chemical precursors.
4：8). Materials include FTO substrates, TaCl5, NH3 gas, NaOH electrolyte, and various chemical precursors.
Experimental Procedures and Operational Workflow:
4. Experimental Procedures and Operational Workflow: For particles: Synthesize oxides, perform ammonolysis to get oxynitrides, prepare photoanodes via EPD with post-necking treatment. For thin films: Deposit TiN buffer via PLD, grow oxynitride films via PRCLA. Characterize using XRD, SEM, RBS/ERDA, UV-Vis, BET. Perform PEC measurements in 0.5 M NaOH with illumination.
5：5 M NaOH with illumination.
Data Analysis Methods:
5. Data Analysis Methods: XRD for structural analysis, RBS and ERDA for composition, Tauc plots for band gap determination, BET for surface area, and potentiostatic scans for stabilized photocurrent densities in PEC.
独家科研数据包，助您复现前沿成果，加速创新突破
获取完整内容
