Unveiling Independent Catalytic Pathways of Dual-Active-Site Catalysts by Time-Resolved Spectroscopy of Reaction Intermediates

Dual-active-site catalysts have been extensively applied in numerous fields. Currently, the widely accepted catalytic pathways of dual-active-site catalysts include synergistic catalysis, tandem catalysis, and single-site catalysis. However, these so-called catalytic pathways fail to dynamically decouple the competing reaction routes in multipathway systems with a single reactant, making it challenging to precisely regulate product selectivity. Therefore, it is of extreme significance to develop rapid and highly efficient strategies to deeply study the reaction pathways of dual-active-site catalysts for manipulating catalyst microstructure and distributing reaction products. In this contribution, we have leveraged time-resolved luminescence spectroscopy with subsecond temporal resolution to dynamically monitor the evolution of reactive intermediates to disclose the independent catalytic pathway for dual-active-site catalysts. It was revealed that the spatially isolated Ni2+-Ov and Ov-Ce3+ dual sites in Ni/CeO2 could drive acetone oxidation through two distinct parallel pathways: Ni2+-Ov generated aldehyde intermediates (CH3CHO*) via weak oxygen activation, while the oxidation of Ov-Ce3+ enabled complete oxidation to CO2* through strong oxygen activation. The independent catalytic pathways of the dual-active site on Ni/CeO2 were further demonstrated by regulating the propionaldehyde oxidation reaction. Our success would advance the rational design of dual-active-site catalysts for pathway-selective catalysis.