Bjerregaard Joachim D, Votsmeier Martin, Grönbeck Henrik
Department of Physics and Competence Centre for Catalysis, Chalmers University of Technology, SE-412 96, Göteborg, Sweden.
Umicore AG & Co. KG, Rodenbacher Chaussee 4, 63457, Hanau, Germany.
Nat Commun. 2025 Jan 11;16(1):603. doi: 10.1038/s41467-025-55859-1.
The performance of Cu-exchanged chabazite (Cu-CHA) for the ammonia-assisted selective catalytic reduction of NO (NH-SCR) depends critically on the presence of paired complexes. Here, a machine-learning force field augmented with long-range Coulomb interactions is developed to investigate the effect of Al-distribution and Cu-loading on the mobility and pairing of complexes. Performing unbiased and constrained molecular dynamics simulations, we obtain unique information inaccessible to first-principle calculations and experiments. The free energy barrier for diffusion between CHA-cages depends sensitively on both the local and distant Al-distribution. Importantly, certain Al-distributions and arrangements of neighboring and cations make paired complexes exothermic with respect to separated configurations. Our results suggest that the NH-SCR activity can be enhanced by increasing the Cu-loading and Al-content. The dynamic interplay between and diffusion is crucial for the mobility and stresses the need to explore large systems including long-range Coulomb interactions when studying diffusion of charged species in zeolites.
铜交换菱沸石（Cu-CHA）用于氨辅助选择性催化还原NO（NH-SCR）的性能关键取决于成对络合物的存在。在此，开发了一种增强了长程库仑相互作用的机器学习力场，以研究铝分布和铜负载量对络合物迁移率和配对的影响。通过进行无偏和受限分子动力学模拟，我们获得了第一性原理计算和实验无法获得的独特信息。CHA笼之间络合物扩散的自由能垒敏感地取决于局部和远处的铝分布。重要的是，某些铝分布以及相邻阳离子和的排列使得成对的络合物相对于分离构型是放热的。我们的结果表明，通过增加铜负载量和铝含量可以提高NH-SCR活性。和扩散之间的动态相互作用对于的迁移率至关重要，并强调在研究带电物种在沸石中的扩散时探索包括长程库仑相互作用的大系统的必要性。
