Spontaneous Nano‐ZrO2 Exsolution from Ni‐Zr‐O Mixed Oxides Enables Facile Fabrication of ZrO2/Ni Inverse Catalysts for Efficient COx Methanation

A spontaneous nano-oxide exsolution strategy was reported as a facile engineering of ZrO₂/Ni inverse catalyst, involving the one-step co-precipitation synthesis of Ni-Zr-O mixed oxide with monodispersed Zr species followed by H₂-induced in situ oxide segregation. The prepared ZrO₂/Ni inverse catalyst was demonstrated to exhibit near-thermodynamic-equilibrium CO_x conversions at 200 °C, while maintaining robust stability under complex simulated syngas conditions.

Abstract

Ni-based inverse catalysts with nano-oxide dispersed on metallic substrates have emerged as promising candidates for low-temperature CO₂ methanation, but it remains challenging in facile synthesis of well-dispersed oxide-metal interactions. Herein, a spontaneous oxide exsolution strategy for the fabrication of Ni-based inverse catalyst via monodispersed Zr species of Ni-Zr-O mixed oxide is demonstrated, where precisely tailored calcination and reduction of the mixed oxide enable in situ nano-ZrO₂ segregation on the metallic Ni matrix. The formation evolution of inverse configuration is elucidated through comprehensive ex situ/in situ characterizations. X-ray photoelectron spectroscopy reveals the electron transfer between the exsolved ZrO₂ and the Ni matrix, indicating the presence of metal-oxide interactions. The prepared ZrO₂/Ni inverse catalyst achieves ∼90% CO₂ conversion and >99% CH₄ selectivity at low-temperature of 200 °C, and also demonstrates excellent catalytic performance and dynamic operational stability in complex CO_x hydrogenation reactions, validating its industrial applicability under realistic syngas-equivalent feedstock conditions.

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