Insight into Dynamic Reorganization Induced Ni/Coo Hybrid Surface on Nico/Cemgal for Ethanol Steam Reforming: Enhanced Activity and Resistance to Coke

Abstract

Revealing the surface structures of bimetallic catalysts under realistic reaction conditions is crucial to design high-performance catalyst and unravel the reaction mechanism. Herein, NiCo bimetal supported on CeO2 doping MgAl2O4 (CeMgAl) with different ratio of Ni/Co were prepared for the ethanol steam reforming (ESR). The dynamic progress for surface components and valence states with time on stream (TOS) and the impacts of this changes on catalytic activities and carbon resistance were focused. Interestingly, the results demonstrate Ni and Co particles exhibit completely opposite behaviors of reorganization and redox under ESR condition, forming the Ni/CoO hybrid surface. The continuous reducing of Ni is beneficial to maintain a stable catalytic activity for the C-C bonds scission, offsetting the activity loss caused by sintering and carbon deposition. And the CoO islands formed by segregation and irreversible oxidation of Co particles are more conducive to H2O activation, preventing the formation of filamentous carbon.

Keywords: NiCo bimetallic catalysts, Dynamic reorganization, Ni/CoO hybrid surface, Ethanol steam reforming, Anti-coke