Photothermal CO₂ methanation offers a clean and sustainable solution to store intermittent renewable energy as synthetic CH₄. However, its high reaction temperature and low space-time yield hinder its industrial application. Here we report an Au/Ce_0.95Ru_0.05O₂ solid-solution catalyst exhibiting a remarkable photothermal CO₂ methanation activity approaching the thermal catalysis limit under visible–near-infrared light irradiation without external heating. Localized surface-plasmon-induced hot-electron injection created abundant oxygen vacancies near the dispersed ruthenium sites, accelerating CO₂ methanation. An approximately 6- to 8-fold increase in the pre-exponential factor was evidenced using Arrhenius plot analysis under visible–near-infrared light irradiation. Using a flow reactor, a photothermal CH₄ production rate of \(473\,{\mathrm{mmol}}\,{\mathrm{g}}_{\mathrm{cat}}^{-1}\,{\mathrm{h}}^{-1}\) was obtained at a gas hourly space velocity of \(80,000\,{\mathrm{ml}}\,{\mathrm{g}}_{\mathrm{cat}}^{-1}\,{\mathrm{h}}^{-1}\) with ~100% CH₄ selectivity, ~75% single-pass CO₂ conversion and excellent durability. Our study offers insights into plasmonic-steered photochemistry, which may open opportunities for the high-yielding synthesis of carbon-based chemicals using solar energy.

光热CO ₂甲烷化提供了一种清洁且可持续的解决方案，可将间歇性可再生能源存储为合成CH ₄。然而，其反应温度高、时空产率低阻碍了其工业化应用。在此，我们报道了一种Au/Ce _0.95 Ru _0.05 O ₂固溶体催化剂，在可见光-近红外光照射下，无需外部加热，表现出显着的光热CO ₂甲烷化活性，接近热催化极限。局域表面等离激元诱导的热电子注入在分散的钌位点附近产生了大量的氧空位，加速了CO ₂甲烷化。在可见光-近红外光照射下，使用阿伦尼乌斯图分析证明指前因子增加了大约 6 至 8 倍。使用流动反应器，光热 CH ₄生产率为\(473\,{\mathrm{mmol}}\,{\mathrm{g}}_{\mathrm{cat}}^{-1}\,{\ mathrm{h}}^{-1}\)是在气时空速为\(80,000\,{\mathrm{ml}}\,{\mathrm{g}}_{\mathrm{cat}} 时获得的^{-1}\,{\mathrm{h}}^{-1}\)具有约 100% CH ₄选择性、约 75% 单程 CO ₂转化率和出色的耐用性。我们的研究提供了对等离子体引导光化学的见解，这可能为利用太阳能高产合成碳基化学品提供机会。