Sustainable electrical energy harvesting via atmospheric water collection using Dual-MOF systems

Abstract

Hydro-electric nanotechnology is touted as a promising next-generation renewable energy system because it employs environmentally-friendly and abundant water as an energy resource for producing electricity efficiently. However, the conventional hydro-electric nanogenerators have some limitations, such as difficulty in continuous and artificial induction of water stream and a low level of energy production for practical use. In this study, we devised a sustainable water harvesting and electrical energy generation system to overcome the limitations of conventional renewable energy. The system was successfully achieved with two distinctive metal-organic frameworks (MOFs), that are, an amine functionalized Zr-based MOF (UiO-66-NH2) particles for atmospheric water harvesting, and a highly conductive Ni3(HITP)2 (HITP = 2,3,6,7,10,11-hexaiminotriphenylene) MOF-grown cotton-fabric for producing electrical energy. The environmentally responsive UiO-66-NH2 harvests water from ambient air and the condensed water spontaneously produces electrical potential between wet- and dry-Ni3(HITP)2, resulting in electrical energy generation with a maximum power and energy densities of 2.6 μW/cm3 and 1.1 mJ/cm3, respectively. Our novel hybrid concept integrating water harvesting and energy generation systems can pave the way for realizing a hydro-electric nanogenerator as a next-generation energy harvesting system in the near future.