Patil Sunaina Shivasharan, Dasari Hari Prasad
Energy and Catalysis Materials Laboratory, Chemical Engineering Department, National Institute of Technology Karnataka, Surathkal, Mangalore, 575025, Karnataka, India.
Environ Sci Pollut Res Int. 2024 Dec 3. doi: 10.1007/s11356-024-35652-1.
Soot generated from the partial combustion of diesel significantly contributes to air pollution, and catalytic oxidation is currently an effective method for removing diesel soot particles. The chromium-doped ceria-praseodymium (Cr-CP) catalyst system is synthesized via solution combustion synthesis and evaluated for soot oxidation activity, with a subsequent kinetics study conducted. The XRD analysis of the catalysts indicated a decrease in crystallite size and increased lattice strain and reactive facet ratios for all Cr-doped CP samples. Raman analysis verified the existence of oxygen vacancy peaks in all chromium-doped CP catalysts. X-ray photoelectron spectroscopy (XPS) revealed the presence of adsorbed HO or molecular water peaks in the O1s spectra for the 5 Cr-CP catalyst, which also exhibited a high concentration of surface Cr ions. Thermogravimetric analysis (TGA) of soot oxidation indicated that 5 Cr-CP exhibited a superior T of 393 ± 2 °C, mostly attributed to the presence of reducible surface Cr ion species. Kinetic analysis was performed on all Cr-doped CP catalysts to assess the kinetic triplets: activation energy, pre-exponential factor, and reaction model. The activation energy was low (87 kJ mol, Ozawa method) for 15 Cr-CP, while the pre-exponential factor was higher for 5 Cr-CP (7.39 × 10 min). The Cr-CP catalyst system adhered to a power law, indicating a phase boundary-controlled reaction characterized by nucleation and growth mechanisms. The consistency between experimental and calculated curves confirmed that the developed catalysts adhered to the Avrami-Erofeev equation (Am) or the nucleation and growth model.
柴油不完全燃烧产生的烟灰对空气污染有显著影响，催化氧化是目前去除柴油烟灰颗粒的有效方法。通过溶液燃烧合成法合成了铬掺杂的二氧化铈 - 镨（Cr-CP）催化剂体系，并对其烟灰氧化活性进行了评估，随后进行了动力学研究。催化剂的XRD分析表明，所有Cr掺杂的CP样品的微晶尺寸减小，晶格应变增加，反应面比率增加。拉曼分析证实了所有铬掺杂的CP催化剂中存在氧空位峰。X射线光电子能谱（XPS）显示，5% Cr-CP催化剂的O1s光谱中存在吸附的HO或分子水峰，该催化剂还表现出高浓度的表面Cr离子。烟灰氧化的热重分析（TGA）表明，5% Cr-CP的T为393 ± 2 °C，表现优异，这主要归因于可还原表面Cr离子物种的存在。对所有Cr掺杂的CP催化剂进行了动力学分析，以评估动力学三要素：活化能、指前因子和反应模型。15% Cr-CP的活化能较低（87 kJ mol，小泽法），而5% Cr-CP的指前因子较高（7.39 × 10 min）。Cr-CP催化剂体系符合幂律，表明其为相边界控制反应，具有成核和生长机制。实验曲线与计算曲线的一致性证实，所开发的催化剂符合阿弗拉米 - 埃罗费耶夫方程（Am）或成核和生长模型。
