Water purification via the solar-driven evaporation of water is a promising solution to alleviate water crises. Herein, a novel three-dimensional interconnected porous structure and ultra-light maize straw/graphene aerogel is facilely synthesized through a low-temperature hydrothermal reduction process and atmospheric drying using microbubbles and ice crystals as templates. The capillary action of the natural pore structure of biomass maize straw accelerated the transportation of water to the heating interface, and the aerogel is also advantageous to use because of the excellent light absorption capacity of graphene. During the synthesis process, the degree of self-assembly, and the density and wettability of the aerogel were controlled via tuning the maize straw/graphene ratio. An optimal sample of maize straw/graphene aerogel displayed a three-dimensional interconnected porous network structure, low density (9.67 mg cm⁻³), excellent mechanical properties (compression strength of up to 11.4 kPa at 70% strain), and high evaporation rate (2.71 kg m⁻² h⁻¹) under 1 solar radiation. More significantly, maize straw/graphene aerogels were nitrogen-doped through the addition of urea, and these outperformed state-of-the-art graphene-based photothermal materials in solar-driven water evaporation, with rates of up to 3.22 kg m⁻² h⁻¹, which was attributed to the formation of a super-hydrophilic, porous, and ultra-light aerogel that further accelerated water transport and the diffusion of water molecules. The nitrogen doping also improved the mechanical properties (compression strength of up to 16.7 kPa at 70% strain), and the aerogel exhibited excellent stability and salt resistance, and accomplished high levels of desalination. The aerogel exhibited excellent mechanical properties and resilience, excellent thermal insulation properties, a wide sunlight absorption spectrum, fast water transmission, and a large pore structure that is conducive to vapor diffusion and high desalination, and, thus, there is great potential for this aerogel to be used for practical applications.

中文翻译：

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基于微泡和冰晶模板的自浮式玉米秸秆/石墨烯气凝胶合成，可实现高效的太阳能驱动界面水蒸发

净水通过的水的太阳能驱动蒸发是一种很有前途的解决方案，以减轻水危机。在此，通过低温水热还原法和以微气泡和冰晶为模板的大气干燥，容易地合成了新颖的三维互连多孔结构和超轻玉米秸秆/石墨烯气凝胶。生物质玉米秸秆的天然孔结构的毛细作用加速了水向加热界面的输送，并且由于石墨烯的优异的光吸收能力，气凝胶也有利于使用。在合成过程中，可通过以下步骤控制气凝胶的自组装程度，密度和润湿性调整玉米秸秆/石墨烯的比例。玉米秸秆/石墨烯气凝胶的最佳样品显示出三维互连多孔网络结构，低密度（9.67 mg cm ^-3），优异的机械性能（在70％应变下的压缩强度高达11.4 kPa）和高蒸发速率1次太阳辐射下（2.71 kg m ^-2 h ^-1）。更重要的是，玉米秸秆/石墨烯气凝胶通过添加尿素进行了氮掺杂，在太阳能驱动的水蒸发中，这些秸秆/石墨烯气凝胶的表现优于最先进的基于石墨烯的光热材料，其速率高达3.22 kg m ^-2 h ^-1，这归因于超亲水，多孔和超轻气凝胶的形成，进一步加速了水的传输和水分子的扩散。氮掺杂还改善了机械性能（在70％应变下的压缩强度高达16.7 kPa），气凝胶显示出出色的稳定性和耐盐性，并实现了高水平的脱盐效果。该气凝胶显示出优异的机械性能和回弹性，优异的隔热性能，宽广的日光吸收光谱，快速的水传输以及有利于蒸汽扩散和高脱盐度的大孔结构，因此，这种气凝胶具有很大的潜力用于实际应用。