高效光热转换碳点基泡沫材料研究

Harvesting solar energy for steam generation has been considered as a promising solution to produce clean water. Seek a new kind of carbon nanomaterials for high-efficiency solar-thermal energy conversion should be a significant part of increasing the clean water. In order to get the carbon nanomaterials with high-efficiency and low cost, here, we demonstrate an extremely simple and standalone solar energy converter consisting of only an as prepared carbon dots-based foam material without any other supporting components. This simple all-in-one material can act as an ideal solar thermal converter capable of capturing and converting sunlight into heat, which in turn can distill water from various water sources into steam and produce clean water under ambient conditions and low solar flux with very high efficiency. Through the studies in the project, a new kind of carbon dots-based foam material with high-efficiency solar-thermal energy conversion will be obtained. Additionally, a model for this converter will be used to understand the high efficiency and mechanism. The as-presented carbon dots-based foam material design can be applied to increase the clean water by using solar energy, it is the first attempt without any report. Carbon dots-based foam material will broaden the species and may open up a new way for designing solar–thermal conversion material for increasing the clean water, and solve this crisis.

拓展碳纳米光热转换材料种类，寻找一种具有高热能利用率的高效光热转换碳纳米材料，对于高效利用太阳能加热水蒸发，增加净水储量，解决人类面临的净水危机具有重要意义。构建可独立漂浮的且具有宽光谱响应的碳点基材料是获得较高热能利用率的高效碳纳米光热转换材料重要途径。本项目将分别通过增加碳点基材料的宽光谱响应和扩大其固-液-汽三相界面的方法提高其光热转换效率和热能利用率。通过本项目的开展，预期获得一种高效光热转换碳点基泡沫材料，同时具有高光热转换效率和高热能利用率；揭示碳点基材料高效利用太阳能加热水蒸发的机制，深刻理解其能量转换过程。这类宽光谱响应（250-2500 nm）碳点基泡沫材料在文献中还未曾被报道；将碳点基材料应用于太阳能加热水蒸发领域也属首次。碳点基泡沫材料将拓展应用于利用太阳能加热水蒸发的碳纳米材料的种类，推动利用太阳能增加净水储量领域的发展，为解决人类面临的净水危机开阔新思路。

拓展光热转换材料种类，寻找一种具有高热能利用率的高效光热转换纳米材料，对于高效利用太阳能加热水蒸发，增加净水储量，解决人类面临的净水危机具有重要意义。构建可独立漂浮的器件结构是获得较高热能利用率的高效光热转换材料重要途径。本项目首先通过水热合成法，制备了镍黑－泡沫镍Ni-NiOx/NF复合多孔材料，吸收率达到90.31%且可以自浮在水面上，从而提高了光热转换效率。种种的优势使得Ni-NiOx/NF的平均蒸发速率达到了1.41 kg m-2 h-1，平均太阳光热转换效率约为93.88%，最优样品的蒸发速率为1.45 kg m-2 h-1，太阳能转换效率为96.30%，并且所得材料Ni-NiOx/NF对渤海海水的淡化效果明显，每种离子的浓度降低了约3个数量级，均低于世界卫生组织（WHO）和美国环境保护署（EPA）的标准，并且通过循环稳定性能测试表明，不论在海水还是淡水中都具有较好的稳定性和较高的蒸发率。然后提出了“单位表面积含水量(Water Mass per Unit Surface Area, WMUA)”的概念，并揭示了分级水管理是提高光热-水蒸发速率的有效策略。该装置成功利用分级水管理策略实现了在1个太阳强度下，利用光热转换性质一般（本征光热转换效率约为 1%-2%）的材料即 可达到1.6-1.8 kg·m-2·h-1 的水蒸发速率，同时实现86.1%-92.0%的太阳能-水蒸气转换效率。材料与器件的深入研发保证了同时具有高光热转换效率和高热能利用率。相关成果拓展了应用于利用太阳能加热水蒸发的碳纳米材料的种类，推动利用太阳能增加净水储量领域的发展，为解决人类面临的净水危机开阔新思路。