Ultra-Efficient, Non-Aqueous Solar Urea Synthesis Over Chemical Environment-Orchestrated Ru

Sunlight-driven catalytic urea synthesis offers a sustainable ambient-pressure pathway for fertilizer production, but energy-intensive liquid-urea separation limits its practicality. Non-aqueous photothermal urea synthesis from gaseous NH₃ and CO₂ offers a promising alternative, though molecular activations under dry and mild conditions remain challenging. Here, we report photothermal urea synthesis over Ru nanocrystals supported on acidic Al₂O₃, basic MgO, and neutral SiO₂, achieving an optimal rate of 2745.71 ± 46.91 µmol_urea g_Ru ^-1 h^-1, an order-of-magnitude higher than state-of-the-arts at ambient pressure. Mechanistic studies elucidate a reaction pathway, initiated photothermally by Ru and orchestrated by an acidic chemical environment that promoted the availability of reactants, in which exothermic N-H bond dissociation of NH₃ matches endothermic C-N coupling with CO₂ in a thermodynamically favorable manner. This work demonstrates an ultra-efficient pioneering synthesis paradigm under near-ambient conditions, circumventing industrial reliance on harsh thermochemical conditions.