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

The metastable Ni/ZrO2 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 ZrO2, 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/ZrO2. Besides, reflux could strengthen the anti-carbon ability but the widened gap between CH4 dissociation and CO2 activation would cause more carbon deposition. The catalyst with reflux for 240 h showed the robust stability for 9000 min (CH4 conversion: 80%; CO2 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.