Efficient Thermo‐Photocatalytic Methanation of Dilute CO 2 via N‐Doped Carbon Encapsulated Co/CoO Nanoparticles

Abstract

Thermo‐photocatalytic CO 2 methanation represents an attractive strategy for addressing global energy and environmental challenges. However, achieving efficient low‐temperature methanation using low‐concentration CO 2 feedstocks remains a formidable challenge. Herein, we report a nitrogen‐doped carbon (NC)‐encapsulated cobalt nanoparticle catalyst decorated with CoO particles for low‐temperature dilute CO 2 methanation under LED irradiation. Density functional theory (DFT) calculations reveal that pyridinic‐N in the NC matrix enhances CO 2 adsorption, enabling the catalyst to react with 0.04% low‐concentration CO 2 . Metallic Co nanoparticles function as active sites for H 2 dissociation, whereas CoO promotes the generation of photogenerated electrons to facilitate CO 2 activation. Under light irradiation, H 2 dissociates into active hydrogen species, which subsequently undergo thermally assisted spillover to CO 2 adsorption sites to form the critical COOH* intermediate. The synergistic effect between photoirradiation and thermal input effectively reduces the operating temperature required for catalytic methanation. Accordingly, the optimal catalyst achieves exceptional performance at 180°C under 420 nm light irradiation, delivering a CH 4 production rate of 344.76 μmol g −1  h −1 , with nearly 100% CH 4 selectivity and 91.6% CO 2 conversion. This work provides a new perspective for the design of high‐performance catalysts for efficient low‐concentration CO 2 conversion.