Abstract: Disclosed herein are highly solar-reflective passive radiative cooling materials in powder form based on calcium phosphates. These materials can be synthesized at a low material cost approaching that of paint additives available on the market, and they are safe, non-toxic, and environmentally-friendly. These materials achieve solar reflectance values ranging from 93% to nearly 98%, making them extremely effective passive radiative cooling materials.

Abstract: Disclosed are apparatuses, systems, methods, and devices for generating high-pressure gas such as hydrogen and oxygen. In one aspect, an apparatus is disclosed. The apparatus includes a reactor which includes a pressure vessel containing a metal compound configured to react with a liquid to generate the high-pressure gas when the liquid is available in the vessel. The reactor includes an outlet configured to pass the generated high-pressure gas out of the vessel. The apparatus also includes a receiver configured to store the generated high-pressure gas generated in the vessel and passed to a receiver via the outlet or passed directly to fuel cell or vehicle tank.