Reaction-driven self-adapting Pd/Nb2O5 steering alkyne semi-hydrogenation

The semi-hydrogenation of alkynes represents a paramount chemical transformation in the synthesis of fine chemicals and pharmaceuticals. However, the structural evolution of active sites during the reaction remains elusive. Here, we constructed a self-adaptive Pd/Nb 2 O 5 catalyst for efficient semi-hydrogenation of alkynes. Mechanistic studies disclose that Pd/Nb 2 O 5 intelligently modulates its structure in response to the specific alkyne type, efficiently preventing Pd poisoning by weakening the strong adsorption of alkynes. During the hydrogenation of aliphatic alkynes, the Pd/Nb 2 O 5 interface undergoes dynamic changes, generating oxygen vacancies (O v ) in situ through hydrogen spillover. In contrast, for the case of reactants of aromatic alkynes, the interface sites remain relatively stable. Coverage-dependent kinetics reveal that the dynamic O v formation of Pd/Nb 2 O 5 is determined by the distinct adsorption mechanism of aromatic and aliphatic alkynes. Due to the evolving interface, Pd/Nb 2 O 5 exhibits a high turnover frequency value of 55,338 h −1 , breaking the linear scaling relationships.