Insight into the role of the channel in photothermal materials for solar interfacial water evaporation

The porous solar-driven interfacial evaporator has attracted substantial interest because of its high performance in converting solar energy into heat for water evaporation. However, the effect mechanism of porous structure (e.g., pore size and porosity) on water evaporation efficiency remains controversial and unclear, which largely restricts the design of high-performance solar evaporators. Herein, a porous solar interfacial evaporator with controllable porous structure was presented by integrating carbonized carboxymethyl cellulose with antimony doped tin oxide (ATO) powder (ATO-C). The experimental results revealed that reducing the porosity of ATO-C could reduce heat loss for heating the water inside channels, thereby improving the evaporation efficiency. Moreover, the synergistic light absorption of carbonized cellulose (in the visible region) and ATO (in the near-infrared light region) enable ATO-C to harvest a large fraction of sunlight (more than 98%) for water evaporation. On the basis, the ATO-C exhibited a water evaporation rate up to 1.44 kg m −2 h −1 under one solar irradiation with an evaporation efficiency of 90.38%, outperforming most previously reported solar evaporators. The current work clarifies the effect mechanism of porosity on evaporation efficiency, which helps to develop high-performance solar interfacial water evaporators.

多孔太阳能驱动界面蒸发器因其在将太阳能转化为用于水蒸发的热量方面的高性能而引起了广泛关注。然而，多孔结构（例如孔径和孔隙率）对水蒸发效率的影响机制仍然存在争议且不明确，这在很大程度上限制了高性能太阳能蒸发器的设计。在此，通过将碳化羧甲基纤维素与锑掺杂的氧化锡（ATO）粉末（ATO - C）相结合，提出了一种具有可控多孔结构的多孔太阳能界面蒸发器。实验结果表明，降低ATO - C的孔隙率可以减少加热通道内水的热量损失，从而提高蒸发效率。此外，碳化纤维素（在可见光区域）和ATO（在近红外光区域）的协同光吸收使ATO - C能够收集大部分太阳光（超过98%）用于水蒸发。在此基础上，ATO - C在一个太阳光照下的水蒸发速率高达1.44千克/平方米·小时，蒸发效率为90.38%，优于大多数先前报道的太阳能蒸发器。目前的工作阐明了孔隙率对蒸发效率的影响机制，这有助于开发高性能的太阳能界面水蒸发器。