In Situ Exsolution of High-Density Ni Nanoparticles in LaAl _0.3 Mn _0.2 Ni _0.5 O _3−δ Cathode for the Electro-Thermocatalytic CO ₂ -Intensified Dry Reforming of Methane

The tandem electro-thermocatalytic system, which integrates dry reforming of methane with reverse water-gas shift and H₂O electrolysis reactions within a solid oxide electrolysis cell, offers an innovative path for the utilization of CO₂-rich feedstocks. The identification of the correlation between the interface-dependent characteristics and both catalytic activity and stability remains a formidable challenge. Herein, we focus on the exsolution of high-density and well-dispersed nanoparticles semiembedded on the LaAl_0.3Mn_0.2Ni_0.5O_3-δ cathode by modulating the Al and Mn co-doping strategy. The substantial and stable metal@perovskite interfacial sites exhibit high intrinsic activity for the tandem electro-thermocatalytic system, which provides high single-pass CO₂ and CH₄ conversion over 92%, syngas yield over 93%, apparent CH₄ reducibility up to 3.91, and a CH₄ turnover frequency of 73.77 mol_CH4 mol_Ni^-1 s^-1 using various CO₂-rich feedstocks (CO₂/CH₄ = 2-4) at 800 °C. In situ electrochemical diffuse reflectance infrared Fourier transform spectroscopy and density functional theory calculations demonstrate the crucial role of *OH electrolysis in the tandem catalysis process. This work elucidates the structure-activity relationship between the metal@support interfacial sites and catalytic activity and stability for the tandem electro-thermocatalytic system.