Rh/Al Nanoantenna Photothermal Catalyst for Wide-Spectrum Solar-Driven CO₂ Methanation with Nearly 100% Selectivity

Solar-powered CO₂ conversion represents a promising green and sustainable approach for achieving a carbon-neutral economy. However, the rational design of a wide-spectrum sunlight-driven catalysis system for effective CO₂ reduction is an ongoing challenge. Herein, we report the preparation of a rhodium/aluminum (Rh/Al) nanoantenna photothermal catalyst that can utilize a broad range of sunlight (from ultraviolet to the near-infrared region) for highly efficient CO₂ methanation, achieving a high CH₄ selectivity of nearly 100% and an unprecedented CH₄ productivity of 550 mmol·g^-1·h^-1 under concentrated simulated solar irradiation (11.3 W·cm^-2). Detailed control experiment results verified that the CO₂ methanation process was facilitated by the localized surface plasmonic resonance and nanoantenna effects of the Rh/Al nanostructure under light irradiation. In operando temperature-programmed Fourier transform infrared spectroscopy confirmed that CO₂ methanation on the Rh/Al nanoantenna catalyst was a multistep reaction with CO as a key intermediate. The design of a wide-spectrum solar-driven photothermal catalyst provides a feasible strategy for boosting CO₂-to-fuel conversion.