Although solar steam generation is an eco-friendly approach for desalinating seawater and purifying wastewater, there are still issues on how to improve the efficiency of solar energy utilization and accelerate the water and heat transport inside the solar-driven water evaporators. Herein, we design a central hollow cylindrical reduced graphene oxide (RGO) foam with vertically and radially orientated channels as a solar steam generation device for efficient water evaporation and purification. The vertically aligned porous channels accelerate upward transport of water to the top evaporation surface, while the radially aligned porous channels facilitate water transport and heat transfer along the radial directions for fully utilizing the heat accumulated inside the central cylindrical hole of the foam. The central hole of the foam plays a highly positive role in accumulating more heat for accelerating the water evaporation, and the newly generated inner sidewall resulted from the central hole can gain extra thermal energy from surrounding environment in the same way as the outer sidewall of the foam due to the surface cooling effect of the water evaporation. As a result, the vertically and radially aligned RGO foam evaporator with central hollow cylinder achieves a high solar steam generation rate of 2.32 kg·m⁻²·h⁻¹ with an exceptional energy conversion efficiency of 120.9% under 1-sun irradiation, superior to the vertically aligned RGO foam without the central hole (1.83 kg·m⁻²·h⁻¹, 96.9%) because of the enhanced water and heat transfer inside the porous channels, and the efficient utilization of environmental energy.

虽然太阳能蒸汽发电是一种海水淡化和废水净化的环保方法，但如何提高太阳能利用效率，加速太阳能水蒸发器内的水和热传输仍然存在问题。在此，我们设计了一种具有垂直和径向通道的中央空心圆柱形还原氧化石墨烯 (RGO) 泡沫作为太阳能蒸汽发生装置，用于高效的水蒸发和净化。垂直排列的多孔通道加速水向上输送到顶部蒸发表面，而径向排列的多孔通道促进水沿径向方向的输送和传热，以充分利用泡沫中心圆柱孔内积聚的热量。泡沫的中心孔在积聚更多热量以加速水分蒸发方面起着非常积极的作用，并且由中心孔产生的新生成的内侧壁可以像泡沫的外侧壁一样从周围环境中获取额外的热能。由于水蒸发的表面冷却效应而产生的泡沫。结果，具有中心空心圆柱体的垂直和径向排列的 RGO 泡沫蒸发器实现了 2.32 kg·m 的高太阳能蒸汽产生率⁻² ·h ⁻¹在1次太阳照射下具有120.9%的优异能量转换效率，优于没有中心孔的垂直排列的RGO泡沫（1.83 kg·m ⁻² ·h ⁻¹ , 96.9%），因为加强多孔通道内的水和热传递，以及环境能源的高效利用。