A nonmetallic plasmonic catalyst for photothermal CO₂ flow conversion with high activity, selectivity and durability

The meticulous design of active sites and light absorbers holds the key to the development of high-performance photothermal catalysts for CO₂ hydrogenation. Here, we report a nonmetallic plasmonic catalyst of Mo₂N/MoO₂-x nanosheets by integrating a localized surface plasmon resonance effect with two distinct types of active sites for CO₂ hydrogenation. Leveraging the synergism of dual active sites, H₂ and CO₂ molecules can be simultaneously adsorbed and activated on N atom and O vacancy, respectively. Meanwhile, the plasmonic effect of this noble-metal-free catalyst signifies its promising ability to convert photon energy into localized heat. Consequently, Mo₂N/MoO₂-x nanosheets exhibit remarkable photothermal catalytic performance in reverse water-gas shift reaction. Under continuous full-spectrum light irradiation (3 W·cm^-2) for a duration of 168 h, the nanosheets achieve a CO yield rate of 355 mmol·gcat^-1·h^-1 in a flow reactor with a selectivity exceeding 99%. This work offers valuable insights into the precise design of noble-metal-free active sites and the development of plasmonic catalysts for reducing carbon footprints.