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.
Porous carbon nanofoam derived from the pyrolysis of a CaCO3 nanoparticle/pitch mixture is first prepared as a novel photothermal material, which shows a high evaporation efficiency of 88% under 1 kW m−2 illumination, thus showing great potential for practical solar steam generation.