Engineering core–shell-structured BaAl2O4 overlaid Ni catalyst with strong metal-support interaction for durable and efficient CH4 dry reforming

Dry reforming of methane (DRM) over Ni-based catalysts is an economically reasonable technology for large-scale CO 2 utilization. However, prolonged Ni sintering and carbon deposition reduce the durability and efficiency of DRM, hindering its engineering application. Herein, we propose a facile approach by combining continuous microscale coprecipitation with solid-state reactions to construct a BaAl 2 O 4 -overlayer-confined Ni catalyst. The 5-wt.%-Ni@BaAl 2 O 4 catalyst exhibited advanced CO 2 and CH 4 conversions of 96% and 86% at 800 °C and a GHSV of 144 L∙g cat. −1 ∙h −1 . Moreover, the k d -CO 2 and k d -CH 4 of Ni@BaAl 2 O 4 were 0.0063 and 0.0029 h −1 ; which are approximately half and one-thirds of those of Ni/BaAl 2 O 4 and slightly better than those of Ni@MgAl 2 O 4 , underscoring the versatility of the proposed synthesis protocol for constructing core–shell structures. XAS, HAADF–STEM–EDS, and CO transmission-IR characterizations confirmed the SMSI of ∼2-nm amorphous BaAl 2 O 4 -overlaid ∼10 nm Ni with an overall mesoporous structure. After a long-term test, the sintering and coking inhibition effects of Ni@BaAl 2 O 4 (10 → 11 nm, 0.55 mg C ∙g cat. −1 ∙h −1 ) outperformed Ni/BaAl 2 O 4 (13 → 22 nm, 1.90 mg C ∙g cat. −1 ∙h −1 ) and Ni@MgAl 2 O 4 . In situ time-resolved CH 4 → CO 2 transient response, DRIFTS experiments, and DFT calculations suggested that Ni@BaAl 2 O 4 and Ni/BaAl 2 O 4 followed the Mars–van Krevelen and Langmuir–Hinshelwood redox mechanisms, respectively. The functional interfacial lattice oxygen promoted the removal of C ads * on Ni and core–shell structure induced fast CO 2 adsorption and CO desorption. The present study provides a facile approach for constructing a stable and active Ni-based core−shell catalyst. Furthermore, it offers novel insights into the functionalities of non-reducible spinel overlayers in the DRM process.