Catalyst deactivation is one of the long-standing challenges in heterogeneous catalysis. Here, we found that the Ni/MgAlO catalyst shows an atmosphere-dependent deactivation behavior during dry reforming of methane (DRM) process, i.e., oxidation and redispersion of Ni near the inlet in an oxidizing atmosphere while coking and sintering of Ni near the outlet in a reducing atmosphere. These structural evolutions of the Ni species are revealed to be driven by the surface oxidation degree of the catalyst, such that it is reversible when the redox atmosphere changes. It inspired us to develop an alternating-feeding gas strategy that periodically changes the gas flow direction to balance the structural evolution of Ni species across catalyst bed through the spontaneous regeneration of deactivated sites, enabling a supra-stable DRM process. This study provides new insights into the catalyst deactivation for DRM process, while opens a new avenue to address catalyst deactivation in various redox-catalyzed processes.

中文翻译：

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活性位点自发再生以防止催化剂失活

催化剂失活是多相催化中长期存在的挑战之一。在这里，我们发现Ni/MgAl2O催化剂在甲烷干重整（DRM）过程中表现出依赖于气氛的失活行为，即入口附近的Ni在氧化气氛中氧化和再分散，而出口附近的Ni则焦化和烧结在还原性气氛中。 Ni物种的这些结构演化被揭示是由催化剂的表面氧化程度驱动的，因此当氧化还原气氛变化时它是可逆的。它启发我们开发了一种交替供气策略，该策略定期改变气流方向，通过失活位点的自发再生来平衡催化剂床上镍物种的结构演化，从而实现超稳定的 DRM 过程。这项研究为DRM过程的催化剂失活提供了新的见解，同时为解决各种氧化还原催化过程中的催化剂失活问题开辟了新途径。