Chen Weicheng, Liu Yangxi, Xu Bolin, Ganesan Muthusankar, Tan Bingqiong, Tan Yuxuan, Luo Fan, Liang Xianghui, Wang Shuangfeng, Gao Xuenong, Zhang Zhengguo, Ye Ruquan, Leung Dennis Y C, Ravi Sai Kishore, Fang Yutang
Key Laboratory of Enhanced Heat Transfer and Energy Conservation of the Ministry of Education, South China University of Technology, Guangzhou, 510640, China.
School of Energy and Environment, City University of Hong Kong, Hong Kong, 999077, China.
Small. 2024 May;20(20):e2306521. doi: 10.1002/smll.202306521. Epub 2024 Feb 16.
Metal-organic frameworks (MOFs) are high-performance adsorbents for atmospheric water harvesting but have poor water-desorption ability, requiring excess energy input to release the trapped water. Addressing this issue, a Janus-structured adsorbent with functional asymmetry is presented. The material exhibits contrasting functionalities on either face - a hygroscopic face interfaced with a photothermal face. Hygroscopic aluminum fumarate MOF and photothermal CuS layers are in-situ grown on opposite sides of a Cu/Al bimetallic substrate, resulting in a CuS-Cu/Al-MOF Janus hygro-photothermal hybrid. The two faces serve as independent "factories" for photothermal conversion and water adsorption-desorption respectively, while the interfacing bimetallic layer serves as a "heat conveyor belt" between them. Due to the high porosity and hydrophilicity of the MOF, the hybrid exhibits a water-adsorption capacity of 0.161 g g and a fast adsorption rate (saturation within 52 min) at 30% relative humidity. Thanks to the photothermal CuS, the hybrid can reach 71.5 °C under 1 Sun in 20 min and desorb 97% adsorbed water in 40 min, exhibiting a high photothermal conversion efficiency of over 90%. CuS-Cu/Al-MOF exhibits minimal fluctuations after 200 cycles, and its water-generation capacity is 3.21 times that of powdery MOF in 3 h in a self-designed prototype in one cycle.
金属有机框架材料（MOFs）是用于大气集水的高性能吸附剂，但水脱附能力较差，需要额外的能量输入来释放捕获的水。为了解决这个问题，本文提出了一种具有功能不对称性的Janus结构吸附剂。该材料在两面展现出截然不同的功能——一面是吸湿面，另一面是光热面。富马酸铝MOF吸湿层和硫化铜光热层原位生长在铜/铝双金属基底的两侧，形成了一种硫化铜-铜/铝-MOF Janus型吸湿-光热混合材料。这两个面分别作为光热转换和水吸附-脱附的独立“工厂”，而中间的双金属层则作为它们之间的“热输送带”。由于MOF具有高孔隙率和亲水性，该混合材料在30%相对湿度下表现出0.161 g/g的水吸附容量和快速的吸附速率（52分钟内达到饱和）。得益于光热材料硫化铜，该混合材料在1个太阳光照下20分钟内可升温至71.5°C，并在40分钟内脱附97%的吸附水，展现出超过90%的高光热转换效率。硫化铜-铜/铝-MOF在200次循环后波动极小，在自行设计的原型中，其在一个循环3小时内的产水能力是粉末状MOF的3.21倍。
