Visible light suppresses carbon formation on Ni/CeO2 catalyst in methane dry reforming reaction.

Dry reforming of methane (DRM) with carbon dioxide produces CO-rich syngas for methanol and Fischer-Tropsch fuel synthesis, but carbon deposition deactivates catalysts and limits commercialization. We suppress detectable carbon accumulation by illuminating a 2Ni/CeO₂₋ₓ nanorod catalyst with visible light (610 mW/cm²) under the tested conditions. Illumination enhances methane conversion, improves H₂ selectivity, and prevents carbon deposition during conversion of undiluted CH₄/CO₂ = 3:1 feed at 400-600 °C. Isotopically labeled ¹⁸O₂ experiments reveal that visible light activates oxygen mobility in nickel-decorated ceria at just 40 °C, compared with 327 °C under thermal stimulation in the dark. Illumination dramatically lowers the activation barriers for surface and lattice oxygen exchange to 18 and 55 kJ/mol through light-induced electron displacement, Ce-O bond weakening, and ceria lattice expansion. These findings establish photo-stimulation as a low-temperature redox trigger for enhanced oxygen ion mobility, enabling improved catalytic performance and broader catalytic and sensing applications.