Institute of Civil Engineering, University of Science and Technology Liaoning
Institute of Chemical Engineering, University of Science and Technology Liaoning

单原子催化剂具有高原子利用率与高催化活性并已广泛应用于CO氧化、CO2还原等领域,对单原子Cu催化剂在催化还原NO领域的微观机理研究有助于开发还原氮氧化物的新型单原子催化剂。阐述量子化学计算参数与模型构建,剖析基于Eley⁃Rideal(E⁃R)、Langmuir⁃Hinshelwood(L⁃H)吸附机理下的NO还原反应路径及N2O还原反应路径,并对NO还原反应动力学进行分析,以密度泛函理论、经典过渡态理论为依据,探究石墨烯量子点担载单原子Cu催化剂(Cu/G)催化还原燃煤烟气中NO的微观反应机理。结果表明,Cu/G非均相还原NO包括N2O的形成与N2的形成2个阶段。由能垒角度分析,在E⁃R作用机制下,NO依次被还原生成N2O和N2的控速步骤能垒值为74.5kJ/mol,小于L⁃H作用机制控诉步骤能垒值。由动力学角度分析,反应温度的升高提升了NO还原反应的速率。反应过程中活性氧的转移导致石墨烯量子点的消耗,随着活性氧转移速率的减弱,最终导致催化剂失活。单原子Cu催化剂催化还原NO的能垒值较金属Cu团簇能垒值有所降低,说明金属分散性对催化剂的活性产生直接影响,也证明单原子催化在还原NO领域具有潜在的前景。

Single⁃atom catalysts (SACs) exhibit high atomic utilization efficiency and superior catalytic activity, andhave been widely applied in fields such as CO oxidation and CO reduction. The investigation of the micro⁃mecha⁃nisms of single⁃atom Cu catalysts in the catalytic NO reduction will contribute to the development of novel single⁃atomcatalysts for the nitrogen oxides reduction. The parameters for quantum chemical calculations and model constructionare described. The reaction pathways for NO reduction and N O reduction, based on the Eley⁃Rideal (E⁃R) andLangmuir⁃Hinshelwood (L⁃H) adsorption mechanisms, are analyzed. Additionally, the kinetics of the NO reductionreaction are studied. Based on density functional theory and classical transition state theory, the micro⁃mechanisms ofheterogeneous NO reduction in coal flue gas catalyzed by single⁃atom copper catalysts supported on graphene quantumdots (Cu / G) were investigated. The results indicate that the reduction process on Cu / G involves two stages: the for⁃mation of NO and the formation of N. Analysis of the energy barriers indicates that, within the Eley⁃Rideal (E⁃R)mechanism, the rate⁃determining steps for the sequential reduction of NO to NO and subsequently to N exhibit lowerenergy barriers, with a value of 74. 5 kJ/ mol, compared to those observed in the Langmuir⁃Hinshelwood ( L⁃H)mechanism. Kinetic analysis demonstrates that an increase in reaction temperature enhances the rate of NO reduction.Throughout the reaction process, the transfer of active oxygen leads to the consumption of graphene quantum dots,and a subsequent decline in the active oxygen transfer rate ultimately results in catalyst deactivation. The energy barri⁃er for the catalytic reduction of NO by single⁃atom Cu catalysts is lower than that of Cu metal clusters, indicating thatthe dispersion of metal atoms has a direct impact on catalytic activity. This also demonstrates the potential of single⁃at⁃om catalysis in NO reduction.

辽宁科技大学大学生创新创业基金资助项目;辽宁省教育厅青年基金资助项目(JYTQN2023237)

李响,安治全,朱亚明,等.单原子Cu催化剂还原燃煤烟气中NO的微观机理研究[J].煤质技术,2024,39(5):11-17.

LI Xiang, AN Zhiquan, ZHU Yaming, et al. Micro⁃mechanism of NO reduction in coal flue gas catalyzed bysingle atom Cu catalyst [J]. Coal Quality Technology, 2024, 39 (5): 11-17.