Porous Carbon Nanofoam Derived From Pitch as Solar Receiver for Efficient Solar Steam Generation.

Photothermal-material-assisted solar-steam generation has recently attracted intensive attention due to its superior evaporation rate with high energy conversion efficiency for desalination. In this work, a simple approach for fabrication of porous carbon nanofoam (PCN) is reported, which is prepared by the carbonization of pitch using a combination of CaCO3 and NaCl templates, Meanwhile, NaCl saturated solution acts as a porogen to produce micropores and mesopores as solar receiver for efficient solar steam generation. The as-prepared PCN shows excellent porosity and mesoporous feature with an average pore size of 26.8 nm. It also shows superior light absorption of 88% and better thermal insulation (thermal conductivity 0.993 W m-1 K-1). Based on these characteristics, the as-prepared PCN can be used as a promising solar receiver. Under 1 sun, 2 sun, and 3 sun irradiation, the PCN-based solar receiver shows high energy conversion efficiencies of 88%, 86%, and 84%, respectively. Taking advantage of the abundant, low-cost, and commercial availability of pitch as well as its simple and cost-effective manufacture method, the PCN-based solar receiver may hold great potential for a broad variety of solar-steam generation applications, for instance, fresh water production, power generation, desalination, and so on.