Metal-organic framework-based composite adsorbents for atmospheric water harvesting: Materials and devices

Water scarcity due to climate change and population growth poses a serious threat to human societies, and adsorbent-based atmospheric water harvesting (AWH) is expected to provide a solution for widespread access to safe drinking water. Metal-organic frameworks (MOFs) have emerged as promising candidates in the field of water adsorption due to their abundant adsorption sites, customizable pore structures, and stable structures. However, single-component MOFs may not be able to fulfill the practical needs due to their low water adsorption capacity and energy-consuming regeneration process. Compositing MOFs with other functional materials and synergistically combining their respective advantages can effectively solve this problem. In this review, we will introduce the hydrolytic stability of MOFs as well as the chemical and structural factors affecting their hydrolytic stability. We also systematically summarize the MOFs-based composite adsorbents (MBCA) reported in recent years and their advantages and disadvantages. In addition, we present a chronological overview of water harvesting devices based on MOFs. Their operation modes, including single-cycle and multi-cycle modes, were investigated. We conclude the review by discussing the challenges and prospects of MBCA for solar water production and provide insights into future developments.