Nitrogen doping sites greatly affected the electronic structure of catalysts. However, identification of nitrogen doping sites in CeO 2 and their effects on catalytic ozonation have never been addressed. Herein, nitrogen was selectively doped at substitutional (N s ) or interstitial sites (N i ) in CeO 2 by simply controlling the heat treatment conditions. The obtained NCe2–400 with 100% N i significantly enhanced the elimination of sulfamethoxazole to 93.7 ± 1.9% within 30 min at the initial solution pH of 6.2. The first-order rate constant reached 8.77 × 10 −2 min −1 , 2.1 and 4.1 times that of 50.1%N s -doped CeO 2 and ozonation, respectively. The experimental and DFT calculation results demonstrate that compared to N s , N i favors the formation of oxygen vacancies (OVs). Both N i and OVs significantly decreased the energy barrier of the adsorption and activation of ozone. This study provides a simple site-tunable N-doping method and gains a new insight into the roles of N i and N s in catalytic ozonation.
Jiaming Zhu,Shiwen Xiong,Genghao Gong,Shiyu Yu,Di Zhang,Zhaoqian Zhang,Shaolu Li,Yunxia Hu
Electroactive membrane filtration (EMF) technology is one of the most promising candidates for next-generation water treatment, and developing electroactive membranes with high catalytic activity and robust stability has become a major focus in the field. Here, a non-solvent induced phase separation (NIPS)/carbonization strategy to fabricate carbon-doped ceramic (CDC) membranes is introduced, which enables precise control over the membrane structure as well as the active N doping sites and lattice defect content in the catalytic material. This structural optimization endows CDC membranes with high efficiency and stability in electrocatalytic organic pollutant degradation. Comprehensive characterization and theoretical calculations reveal that tuning the carbonization temperature significantly enhances the electrocatalytic properties of carbon materials by modifying nitrogen deposition sites and generating lattice defects. Using EMF, the optimized CDC membrane achieves over 99% dye removal efficiency with very low energy consumption (0.011 kWh m −3 order −1 ). Furthermore, the optimized small and uniform sponge-like pore structure imparts the CDC membranes with high mechanical strength, excellent antifouling properties, and long-term operational stability (>12 h). This study provides insights into the impact of both macro- and microstructural characteristics on EMF performance while elucidating the underlying mechanisms.
危险品化学品经营许可证（带存储）