Graphitic carbon nitride (g-C₃N₄) nanosheets were synthesized by exfoliating bulk g-C₃N₄ with a thermal treatment under H₂ for the first time.

Solar-driven distillation and desalination are promising technologies for large-scale water purification. Internal micro-channels are critical for the performance of a steam generation device in consideration of thermal management and water transportation. Here, we designed novel porous three-dimensional carbon foams (CFs) with unique interconnected channels and rough surfaces via alkali activation of naturally abundant wood. Promoted by the rough surface, the CFs can harvest more than 97% of the energy of the solar spectrum. The hydrophilic interconnected micro-channels of the CFs enhance water transportation and heat localization. Benefiting from these advantages, the highest steam generation efficiency of the CFs reaches 80.1% under 1 kW m⁻². In addition, the CFs also show high stability under harsh conditions and high activity in desalination of seawater. With the unique interconnected micro-channels, this porous carbon device offers a scalable, cost-effective and efficient choice for solar steam generation.