Solar steam generation (SSG) using hydrogels is emerging as a promising technology for clean water production. Herein, a novel oxygen-doped microporous carbon hydrogel (OPCH), rich in hydrophilic groups and micropores, has been synthesized from microalgae to optimize SSG. OPCH outperforms hydrogels with hydrophobic porous carbon or nonporous hydrophilic biochar, significantly reducing water's evaporation enthalpy from 2216.06 to 1107.88 J g and activating 42.3 g of water per 100 g for evaporation, resulting in an impressive evaporation rate of 2.44 kg m h under one sun. A detailed investigation into the synergistic effects of hydrophilic groups and micropores on evaporation via a second derivative thermogravimetry method revealed two types of bonded water contributing to enthalpy reduction. Molecular dynamics simulations provided further insights, revealing that the hydrophilic micropores considerably decrease both the number and the lifetime of hydrogen bonds among water molecules. This dual effect not only reduces the energy barrier for evaporation but also enhances the kinetic energy needed for the phase transition, significantly boosting the water evaporation process. The sustained high evaporation rates of OPCH, observed across multiple cycles and under varying salinity conditions, underscore its potential as a highly efficient and sustainable solution for SSG applications.

中文翻译：

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亲水官能团和微孔对新型碳水凝胶中水蒸发的协同效应，用于高效太阳能蒸汽产生


使用水凝胶的太阳能蒸汽发电（SSG）正在成为一种有前景的清洁水生产技术。在此，我们从微藻中合成了一种富含亲水基团和微孔的新型氧掺杂微孔碳水凝胶（OPCH），以优化SSG。 OPCH的性能优于疏水性多孔碳或无孔亲水生物炭的水凝胶，可将水的蒸发热从2216.06 J g显着降低至1107.88 J g，每100 g可活化42.3 g水进行蒸发，在一个太阳下的蒸发速率高达2.44 kg m h。通过二阶导数热重分析方法详细研究了亲水基团和微孔对蒸发的协同效应，揭示了两种有助于降低焓的键合水。分子动力学模拟提供了进一步的见解，表明亲水微孔大大减少了水分子之间氢键的数量和寿命。这种双重效应不仅降低了蒸发的能垒，而且增强了相变所需的动能，显着促进了水的蒸发过程。在多个循环和不同盐度条件下观察到的 OPCH 持续高蒸发率，凸显了其作为 SSG 应用的高效和可持续解决方案的潜力。