Generation of active oxygen species by CO₂ dissociation over defect-rich Ni-Pt/CeO₂ catalyst for boosting methane activation in low-temperature dry reforming: Experimental and theoretical study

Herein, we demonstrated a one-pot complex combustion method to synthesize defect-rich Ni-Pt/CeO₂ catalyst having oxygen vacancy sites (V_o) by incorporating Ni and Pt species into the ceria lattice. These V_o sites are highly active for dissociating CO₂ into reactive oxygen species and CO at low temperature. CH₄-TPSR demonstrated that surface reactive oxygen species are more selective than lattice oxygen toward the formation of syngas. The catalytic properties and activity of the synthesized catalysts were also compared with the conventionally impregnated catalyst. In-situ DRIFT and Raman study revealed reactive oxygen-assisted CH₄ activation via the formation of CH_xO intermediate. DFT calculation also showed the facile formation of CH₃O and CH₂O species over the bimetallic NiPt-CeO₂(111) catalyst surface. The Ni-Pt/CeO₂ (0.5 wt%Pt-2 wt%Ni) catalyst showed superior activity and stability with ∼86% conversion of CH₄ and CO₂ at 675 °C, where the H₂/CO ratio is one. The catalyst was stable up to 700 h time-on-stream.