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Gradient Vertical Channels within Aerogels Based on N-Doped Graphene Meshes toward Efficient and Salt-Resistant Solar Evaporation
ACS Sustainable Chemistry & Engineering ( IF 7.1 ) Pub Date : 2020-03-20 , DOI: 10.1021/acssuschemeng.0c00853 Xiangyu Meng 1 , Jianhui Yang 1 , Seeram Ramakrishna 2 , Yueming Sun 1 , Yunqian Dai 1
ACS Sustainable Chemistry & Engineering ( IF 7.1 ) Pub Date : 2020-03-20 , DOI: 10.1021/acssuschemeng.0c00853 Xiangyu Meng 1 , Jianhui Yang 1 , Seeram Ramakrishna 2 , Yueming Sun 1 , Yunqian Dai 1
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In the drive toward energy harvesting, graphene and their derivations are the most promising photothermal materials for solar evaporation. Here is a facile approach for constructing gradient vertical channels within a ring-like three-dimensional (3D) aerogel based on porous N-doped reduced graphene oxide (N-RGO) meshes toward interfacial water evaporation. Intriguing gradient microchannels are constructed by introducing a concentration gradient of NH4OH (as antifreeze) within the N-RGO hydrogel before traditional freeze-drying. Based on both theoretical simulation and experimental demonstrations, aerogels with ring-like photothermal structures harvest light without angle dependence and exhibit ring-by-ring thermal insulation and high photothermal conversion efficiency (74.8%). Moreover, unique 3D gradient vertical microchannels concentrate water into hot regions and achieve effective interfacial evaporation, leading to a high evaporation rate (2.53 kg·m–2·h–1, normalized to the evaporation area including both the top and side surface) and solar-to-vapor conversion efficiency (90.3% and 41% higher than that of honeycomb-like aerogels). Besides, the controllable N-doping in terms of concentration and configurations (i.e., pyridinic and graphitic N-dopants) greatly enhances the water transport and evaporation. The aerogel exhibits salt resistance in highly concentrated saline water under 5 h of cycling and also shows structural stability under the corrosive liquid and external mechanical compression. Our work provides attractive ways of constructing the 3D gradient ordered microstructures by assembling graphene meshes and achieving effective thermal management and interfacial water evaporation.
中文翻译：
基于N掺杂石墨烯网格的气凝胶内的梯度垂直通道朝向高效且耐盐的太阳蒸发
在能量收集的过程中，石墨烯及其衍生物是最有前途的用于太阳能蒸发的光热材料。这是一种在环形三维（3D）气凝胶内构造梯度垂直通道的简便方法，该气凝胶基于向界面水蒸发的多孔N掺杂还原型氧化石墨烯（N-RGO）网格。引人入胜的梯度微通道是通过引入NH 4的浓度梯度构建的传统冷冻干燥之前，N-RGO水凝胶中的OH（作为防冻剂）。根据理论模拟和实验论证，具有环形光热结构的气凝胶可收集光而不受角度的影响，并具有逐环的隔热性和较高的光热转换效率（74.8％）。此外，独特的3D梯度垂直微通道将水集中到高温区域并实现有效的界面蒸发，从而导致高蒸发速率（2.53 kg·m –2 ·h –1，归一化为蒸发面积，包括顶面和侧面）和太阳到蒸气的转换效率（比蜂窝状气凝胶分别高90.3％和41％）。此外，就浓度和构型（即吡啶和石墨N型掺杂剂）而言，可控的N掺杂大大提高了水的输送和蒸发。气凝胶在循环5小时后的高浓度盐水中显示出耐盐性，并且在腐蚀性液体和外部机械压缩下也显示出结构稳定性。我们的工作提供了通过组装石墨烯网格并实现有效的热管理和界面水蒸发来构建3D梯度有序微结构的诱人方法。
更新日期：2020-03-21
中文翻译：
基于N掺杂石墨烯网格的气凝胶内的梯度垂直通道朝向高效且耐盐的太阳蒸发
在能量收集的过程中，石墨烯及其衍生物是最有前途的用于太阳能蒸发的光热材料。这是一种在环形三维（3D）气凝胶内构造梯度垂直通道的简便方法，该气凝胶基于向界面水蒸发的多孔N掺杂还原型氧化石墨烯（N-RGO）网格。引人入胜的梯度微通道是通过引入NH 4的浓度梯度构建的传统冷冻干燥之前，N-RGO水凝胶中的OH（作为防冻剂）。根据理论模拟和实验论证，具有环形光热结构的气凝胶可收集光而不受角度的影响，并具有逐环的隔热性和较高的光热转换效率（74.8％）。此外，独特的3D梯度垂直微通道将水集中到高温区域并实现有效的界面蒸发，从而导致高蒸发速率（2.53 kg·m –2 ·h –1，归一化为蒸发面积，包括顶面和侧面）和太阳到蒸气的转换效率（比蜂窝状气凝胶分别高90.3％和41％）。此外，就浓度和构型（即吡啶和石墨N型掺杂剂）而言，可控的N掺杂大大提高了水的输送和蒸发。气凝胶在循环5小时后的高浓度盐水中显示出耐盐性，并且在腐蚀性液体和外部机械压缩下也显示出结构稳定性。我们的工作提供了通过组装石墨烯网格并实现有效的热管理和界面水蒸发来构建3D梯度有序微结构的诱人方法。
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