Portable dual-functional hygroscopic device for efficient atmospheric water harvesting and hydrogen production in diverse environments

Abstract

Developing integrated functional atmospheric water harvesting and hydrogen production devices based on cost-effective porous carbon materials is crucial for advancing their implementation and addressing multiple environmental challenges. Here, we fabricate a dual-functional hygroscopic composite device (HCD) under mild conditions, capable of obtaining clean water and hydrogen using sunlight and atmospheric moisture. The hierarchical HCD is designed as an ideal solar absorber by incorporating polyvinyl alcohol hydrogel into macroporous carbon and hosting dispersed LiCl and NiCoP10 catalyst. The HCD features hygroscopic and dual-functional photothermal interfaces with kinetic differentiation, exhibiting excellent machinability, high light absorptivity, optimized hygroscopic components, and favorable water evaporation enthalpy. This design, combined with a customized strategy, ensures consistently efficient performance of HCD, achieving a notable daytime water production performance of 3.89 kg·m−2·d−1 at a low total cost of 27.68 $·kg−1·d. The HCD can catalyze ammonia borane hydrolysis to generate hydrogen in various environments including cold and water-scarce conditions. Furthermore, the HCD shows potential for hydrogen energy system, achieving an open circuit voltage output ranging from 0.41 to 0.493 V. The miniaturized HCD flexibly provides a comprehensive solution for water and energy applications in complex environments, with significant potential for widespread implementation.