The passive cooling technology is refrigerant-free and energy-free, making it an appealing alternative to reduce the energy consumption of traditional cooling systems. Although effective in optical design, the materials involving optical structures and metal reflectors are rarely cost-effective or readily applicable. Radiative cooling materials with promising optical properties and good practical applicability remain an urgent research need. We present a simple and scalable method to fabricate a dual-layer nanoparticle-polymer hybrid coating which achieves a high diffused solar reflection of 92.2 % without using metal reflectors, and a strong mid-infrared emission of 95.3 % within the atmospheric window. The coating allows continuous sub-ambient cooling in both daytime and nighttime. Promisingly, the coating reaches about 4 °C lower temperature than ambient under intensive solar irradiation, along with a 78.9 Wm⁻² cooling power generation. Moreover, the cooling coating exhibits great reliability and cooling effect when applied as an exterior coating on model houses and the roof of a real building. Applying the proposed material as a roofing material is capable to save cooling energy across various climate zones, especially in the hot climate, which confirms the material’s possibility for carbon reduction and tackling global climate change.

被动冷却技术无需制冷剂和能源，使其成为降低传统冷却系统能耗的有吸引力的替代方案。尽管在光学设计中有效，但涉及光学结构和金属反射器的材料很少具有成本效益或易于应用。具有良好光学性能和良好实际应用性的辐射冷却材料仍然是迫切的研究需求。我们提出了一种简单且可扩展的方法来制造双层纳米粒子-聚合物混合涂层，该涂层在不使用金属反射器的情况下实现了 92.2% 的高漫反射太阳反射，并在大气窗口内实现了 95.3% 的强中红外发射。该涂层允许在白天和夜间持续进行低于环境温度的冷却。很有希望，⁻²冷却发电。此外，该冷却涂料在用作样板房和真实建筑物屋顶的外墙涂料时表现出良好的可靠性和冷却效果。将提议的材料用作屋面材料能够在各个气候区节省冷却能源，尤其是在炎热的气候中，这证实了该材料在减少碳排放和应对全球气候变化方面的可能性。