Photothermal Steering of the CH ₄ ─CO ₂ Coupling Pathway and Coke‐Suppression Mechanism by Ni ^δ+

ABSTRACT

High‐temperature carbon deposition is a major challenge in dry reforming of methane (DRM), mainly arising from insufficient generation and sluggish migration of reactive oxygen species. Combining interfacial vacancy engineering with photothermal synergistic catalysis is a promising solution, yet their synergistic mechanism remains unclear. Here, a simple alkaline etching strategy was employed to construct stable Ni ^δ+ –O _v –Al interfacial sites on a NiMgAl‐A catalyst. These sites enhanced Ni dispersion and promoted continuous electron transfer from Ni to the support. In situ characterization and theoretical calculations revealed that Ni ^δ+ –Ov–Al sites serve as both intrinsic active centers for CH ₄ /CO ₂ activation and interfacial electron traps that improve charge separation under illumination. As a result, photogenerated carriers accelerate reactive oxygen species formation, facilitating the direct conversion of CH ₄ and CO ₂ into CH _x O* intermediates and effectively suppressing coke formation. Photothermal DRM tests at 600°C demonstrated strong synergy between photoelectrons and Ni ^δ+ –Ov–Al sites. Compared with pristine NiMgAl, NiMgAl‐A increased CH ₄ and CO ₂ conversion rates by 1.55 and 1.61 times, respectively, while reducing the carbon deposition rate from 0.57 to 0.12 g·h ⁻¹ . This work provides mechanistic insight into oxygen‐vacancy/photoelectron synergy for designing efficient carbon‐resistant DRM catalysts.