Given
the green developments in interfacial solar steam generation
(ISSG), a biobased evaporator with excellent photothermal conversion
efficiency is urgently needed to address the freshwater shortage.
However, it is still challenging that biobased evaporators like wood
and bamboo are underutilized due to the capillary actions in different
channel directions. Herein, we investigated the channel structural
properties of bamboo veneer evaporators for contrast analysis between
bamboo transverse sections (BTR) and bamboo tangential sections (BTA).
The one-step torrefaction method was used to improve the optical absorption
of bamboo lignin in the 200–2500 nm band. Owing to the perpendicular
channel design, the BTR evaporator conducting straight energy loss
to the bulk water restricts the performance. The BTA evaporator’s
parallel channel design with a micronano unit presents better photothermal
management (surface temperature could reach 57.1 °C under 1 kW/m2 illumination), leading to efficient evaporation performance
(1.425 kg/m2 h). These findings contribute to our cognition
of solar-driven water transport and suggest a parallel channel ISSG
design to develop efficient biobased ISSG in freshwater produce from
seawater or sewage.