The photothermal pathway for converting carbon dioxide (CO₂) into hydrocarbons presents an effective and straightforward production for solar fuels. Nonetheless, the rational design of a robust solar-driven catalytic system for efficient CO₂ conversion remains a persistent challenge. In this work, we elaborately construct a multi-shell Au@Rh nanoantenna reactor for photothermal CO₂ methanation. The plasmonically active multi-shell Au structure serves as “antenna”, and the catalytically active Rh nanoparticles function as “reactor”. The reactor exhibits a superior CH₄ yield rate and nearly 100% selectivity, in comparison with the other Au structures (single-shell (SS) and nanoparticle) and the kinds of active sites (Ru, Ir, and Co). The well-arranged Au nanoparticles in multi-shell structure provide the collective plasmon-coupled excitation, leading to the strong localized surface plasmon resonance (LSPR) effect. Then, the antenna could convert the wide-spectrum solar energy to high surface temperature and enhanced electric field. The in-situ spectra and theoretical calculation indicate that the CO₂ methanation reaction in Au@Rh nanoantenna reactor follows the formyl pathway. The strong electron–proton coupling transfer ability of Au@Rh nanoantenna reactor contributes to the complex reaction pathway for CO₂ methanation. Especially, compared with Au catalyst, both the formation of $\mathrm{C}\mathrm{O}\mathrm{O}\mathrm{H}\ast$ intermediate and the key transformation from $\mathrm{C}\mathrm{O}\ast$ to $\mathrm{C}\mathrm{H}\mathrm{O}\ast$ in Au@Rh nanoantenna reactor were promoted through the adequate supply of proton–electron pair and the strong interaction between Au and Rh sites. The ingenious design for nanoantenna reactor and the new findings in photothermal CO₂ methanation will inspire the development of mild hydrogenation for boosting CO₂-to-fuel conversion.

Emerging as a prominent area of focus in energy conversion and storage technologies, the development of highly active metal-based single-atom catalysts (SACs) holds great significance in searching alternatives to replace precious metals toward the efficient, stable, and low-cost hydrogen evolution reaction (HER), as well as the oxygen evolution reaction (OER) and the oxygen reduction reaction (ORR). Combining the tremendous tunability of ligand and coordination environment with rich metal-based electrocatalysts can create breakthrough opportunities for achieving both high stability and activity. Herein, we propose a novel and stable holey graphene-like carbon nitride monolayer g-C₁₆N₅ (N₄@g-C₁₆N₃) stoichiometries interestingly behaving as a natural substrate for constructing SACs ((TM-N₄)@g-C₁₆N₃), whose evenly distributed holes map rich and uniform nitrogen coordination positions with electron-rich lone pairs for anchoring transition metal (TM) atoms. Then, we employed density functional theory (DFT) calculations to systematically investigate the electrocatalytic activity of (TM-N₄)@g-C₁₆N₃ toward HER/OER/ORR, meanwhile considering the synergistic modulation of H-loading and O-coordination ((TM-N_xO_4−x)@g-C₁₆N₃-H₃, x = 0–4). Together a “four-step procedure” screening mechanism with the first-principles high-throughput calculations, we find that (Rh-N₄) and (Ir-N₂O_2-II) distributed on g-C₁₆N₃-H₃ can modulate the adsorption strength of the adsorbates, thus achieving the best HER/OER/ORR performance among 216 candidates, and the lowest overpotential of 0.098/0.3/0.46 V and 0.06/0.48/0.45 V, respectively. Additionally, the d-band center, crystal orbital Hamilton population (COHP), and molecular orbitals are used to reveal the OER/ORR activity source. Particularly, the Rh/Ir-d orbital is dramatically hybridized with the O-p orbital of the oxygenated adsorbates, so that the lone-electrons incipiently locate at the antibonding orbital pair up and populate the downward bonding orbital, allowing oxygenated intermediates to be adsorbed onto (TM-N_xO_4−x)@g-C₁₆N₃-H₃ appropriately.