A composite material formulated for slow release of a small molecule in seawater includes a porous inorganic oxide framework and micelles embedded within the pores of the framework. The micelles include a surfactant and a small molecule, the surfactant being present in the composite material at no more than 80 parts by weight per 100 parts by weight inorganic oxide, the composite material being stable in seawater for releasing the small molecule over at least 20 days.
