Emergent Ni catalysts induced by nitride-to-oxide transformation for coking and sintering resistant dry reforming of methane

Abstract

Dry reforming of methane (DRM) can catalytically convert CH₄ and CO₂ into syngas, which can alleviate the greenhouse effect and upgrade the value of greenhouse gases. However, Ni-based catalysts are plagued by activity degradation resulting from metal sintering and coking. In this study, emergent Ni catalysts with strong metal–support interactions (SMSI) induced by nitride-to-oxide transformation have been engineered. The SMSI effectively suppresses metal sintering during the DRM reaction. At the same time, the formation of plentiful oxygen vacancies during the element exchange process vastly facilitates the adsorption and activation of reactant molecules. The SMSI suppresses metal sintering during the fabrication of catalysts and the DRM reaction, resulting in higher metal dispersion (1.54% vs. 1.21%) and less metal sintering. The formation of plentiful oxygen vacancies during the element exchange process facilitates the adsorption and activation of reactant molecules, resulting in a higher turnover frequency of CH₄ (3.6 vs. 2.3 s⁻¹) and CO₂ (5.3 vs. 3.1 s⁻¹). Additionally, the abundant oxygen vacancies promote the adsorption and activation of CO₂ and facilitate the elimination of deposited carbon, with no carbon deposition after 50 hours of the DRM reaction. This work has discovered the SMSI induced by structural changes, which provides a novel approach for constructing catalysts with better sintering and coking resistance for other applications.