Ultrahigh solar steam generation rate of a vertically aligned reduced graphene oxide foam realized by dynamic compression

Abstract

Although solar steam generation is a promising water purification approach for alleviating the global shortage of clean water, the water evaporation rate of non-organic systems is still far from perfection. Herein, a vertically aligned reduced graphene oxide (V-RGO) foam with numerous vertical channels is fabricated as a solar-thermal energy converter for efficient solar steam generation. For the first time, dynamic compression is proven to be an efficient strategy to adjust the energy state of water in the pore channels of V-RGO foams. With an optimal compression, the vaporization enthalpy of water significantly decreases because of the increased proportion of intermediate water, resulting in a much faster water evaporation rate under solar-light irradiation. The average water evaporation rate under 1-sun irradiation reaches 3.39 kg m⁻² h⁻¹, representing the highest value among those for inorganic materials reported previously. This dynamic compression provides a novel strategy for purification of wastewater and desalination of seawater.