Rationally constructing metastable ZrO2 supported Ni catalysts for highly efficient and stable dry reforming of methane.

The metastable Ni/ZrO 2 catalysts were rationally constructed via reflux treatment and employed for dry reforming of methane. Reflux could suppress the transformation and improve the stability of the metastable ZrO 2 , as well as enrich its pore structure. Meanwhile, acidity-basicity, Zr3+ and oxygen vacancies were also promoted. Additionally, Ni dispersion was remarkably improved with increasing reflux time due to the abundant pores and enhanced metal-support interaction. These results illustrated the evaluation that prolonging reflux time could significantly proliferate the performance of Ni/ZrO 2. Besides, reflux could strengthen the anti-carbon ability but the widened gap between CH 4 dissociation and CO 2 activation would cause more carbon deposition. The catalyst with reflux for 240 h showed the robust stability for 9000 min (CH 4 conversion: 80 %; CO 2 conversion: 88 %) at 750 °C. Furthermore, the mechanisms were discussed to unravel the origin of the accelerated performance by reflux and provide some references for designing efficient Ni-based catalyst. [Display omitted] • Reflux stabilizes the metastable ZrO 2 with abundant pore structure and more acid-base/defect sites. • Reflux enhances metal-support interaction, thereby improving Ni dispersion. • Catalyst after reflux shows higher activity, better stability and stronger anti-carbon ability. • Balancing the rate of CH 4 dissociation and CO 2 activation is crucial for restraining carbon formation. • Reaction mechanisms are discussed to unravel the origin for the performance improvement by reflux. [ABSTRACT FROM AUTHOR]