One-Pot Microemulsion Strategy for Fabricating Ni@MgAl2O4 Catalysts with Enhanced Sintering and Coking Resistances for Dry Reforming of Methane

In the context of increasing global energy demand and greenhouse gas (GHG) emissions, the dry reforming of methane (DRM) to syngas can simultaneously convert CH₄ and CO₂ into syngas (H₂ and CO), which is both environmentally friendly and energy valuable. Carbon deposits and the sintering of active metals often lead to catalyst deactivation. In this work, one-pot microemulsion and impregnation methods have been employed to synthesize Ni@MgAl₂O₄ and Ni/MgAl₂O₄ catalysts, respectively, and the effects of different calcination temperatures on the physicochemical properties of the loaded catalysts were investigated. It was shown that Ni@MgAl₂O₄ exhibited good structural stability and strong metal-support interaction. In addition, the surfaces of Ni@MgAl₂O₄-800 are rich in adsorbed oxygen species and basic sites, which are favorable for CO₂ adsorption and activation and inhibit carbon deposition. In the DRM reaction, the Ni@MgAl₂O₄-800 catalyst exhibited the highest CH₄ and CO₂ conversions in the tested temperature range. Its initial conversion of CH₄ and CO₂ was 92.5 and 93.1%, respectively (800 °C, WHSV = 30,000 mL·g_cat^-1·h^-1). After 20 h of continuous running, the decreases of CH₄ and CO₂ conversion were <5 and 9%, respectively, and no obvious carbon deposition was observed, which showed good reactivity and anticarbon deposition performance.