Design and Manufacturing of Composite Kirigami Metamaterials for High-Yield Water Harvesting and Sustainable On-Site Purification

Achieving sustainable access to clean water and sanitation is a key priority within the United Nations’ 17 Sustainable Development Goals. Atmospheric fog represents a vast and sustainable freshwater resource, yet its large-scale utilization remains hindered by the low collection efficiency due to aerodynamic deflection of fog-laden wind and poor water quality caused by airborne contaminants. Existing fog harvesting and purification technologies that integrate collection surfaces with photocatalysts face inherent trade-offs: sufficient contaminant degradation requires prolonged droplet retention, which in turn impedes droplet drainage and reduces the clean water yield.This project proposes a transformative solution through the composite reentrant kirigami metamaterial design that decouples and independently optimizes fog capture and water purification. The design integrates a geometry-dominant perforated kirigami scaffold at the front with a visible-light-responsive photocatalytic layer at the back. The kirigami scaffold, featuring optimized reentrant geometries, can reshape the aerodynamics near the substrate, suppressing fog deflection and enhancing droplet interception, while the porous photocatalytic layer, with refined material configurations, enables continuous and on-site purification of captured fog droplets. By separating and independently tuning the geometric and material effects of these two layers, the proposed system overcomes the long-standing trade-off between droplet retention and drainage, providing a new pathway for highly efficient and high-yield clean water harvesting.⁠⁠⁠⁠⁠⁠⁠Our preliminary results demonstrated that the composite kirigami produced a clean water yield of 18.1 L/m2/h under an organic contaminant concentration of 0.5 ppm, corresponding to a superior purification efficiency of 96.7% and a high collection efficiency of 39.2%. Building on this foundation, this project will develop a comprehensive framework to characterize and optimize the intertwined processes of fog capture and purification, deepen mechanistic insight, and enable adaptable, scalable implementation. Through a comprehensive experimental-numerical-analytical framework, we will elucidate the aerodynamic mechanisms behind geometry-enhanced fog capture and identify optimal design parameters. Further, we will investigate how the conjunction between scaffold geometry and the photocatalytic layer property coordinates synchronized water transport and contaminant decomposition dynamics for highly efficient and high-yield clean water production. Comprehensive evaluations spanning diverse atmospheric contaminants and environmental conditions will be conducted to validate the versatility and practicality of our approach. Finally, the optimized composite kirigami sample will be scaled up and tested in outdoor environments. The fundamental and technical outcomes generated by this project will establish a new paradigm for high-yield, high-efficiency, and scalable fog harvesting and on-site purification, offering a transformative pathway toward sustainable and decentralized clean-water solutions.