Regenerable Ni-Au/La₂O₃ catalysts for dry reforming of methane

Dry reforming of methane (DRM) has been proposed as an effective way of converting CO₂ and CH₄, two major greenhouse gases, into synthesis gas (H₂ + CO), a ubiquitous feedstock for various chemical industries. Ni-based bimetallic catalysts have been widely explored as an attractive route to improve DRM activity, selectivity, and stability. In this study, we synthesized LaNiO₃ (LNO) and 1% Au-doped LaNiO₃ (Au/LaNiO₃ – A/LNO) using the modified sol-gel method. The material properties were studied using various characterization techniques, including XRD, BET, H₂-TPR, TPO, STEM-HAADF with EDX mapping, Raman spectroscopy, and XPS. Ni nanoparticles with sizes ranging from 10 to 70 nm were successfully exsolved from the perovskite material after reduction at 800 °C. DRM activity of the reduced catalysts was probed from 400 to 800 °C. The Au-doped LNO exhibits significant enhancement in DRM activity at a lower temperature range (600–700 °C) compared to LNO. The A/LNO was also shown to retard coke formation and improve the selectivity for DRM. A computational study using density functional theory (DFT) reveals that the Ni₃Au sites have a lower methane activation barrier due to the formation of Ni-Au alloy and the synergetic effect between Ni and Au.