Diamond-doped silica aerogel for solar geoengineering

Even though aerosol injection into stratosphere is one of the most promising solar geoengineering techniques, sulfate aerosols, which are suggested for such an application, show significant drawbacks such as infra-red (IR) absorption and ozone degradation. The development of new materials for such application that would exhibit substantial up-scattering, with non-IR absorption to allow a cooling effect are needed. Here, a novel composite material comprised of diamonds dispersed in a silica aerogel network is investigated and compared to pure silica aerogel. Silica aerogels are ultralight, highly porous, transparent and can host particles, while fulfilling particle size limitation in terms of potential health risks for humans during respiration. Morphology of both the diamonds and the silica aerogels composites has been studied. The diffuse reflectance of the diamond powders, pure silica aerogels, and the diamond-doped silica aerogels have been measured for comparison. Our experimental work assesses the proposed concept of materials, including discussion and recommendations for the improvements of the synthetized materials. The obtained results are promising and could stimulate further in-depth studies in similar materials with a potential for applications in solar geoengineering.