Co-designed dual-ambient energy harvester hydrogel for hydrogen production and electricity generation

In the quest to scavenge and convert environmental energy into useable green power, the development of materials that can efficiently harvest from multiple ambient energy sources remains challenging. Essentially, the reconciliation of differing material and structural requirements necessary for distinct functionalities is still a significant obstacle. In this work, a co-design approach has been taken to tailor a hydrogel capable of meeting the specific demands of two energy conversion processes; solar-induced hydrogen generation and evaporation-induced electricity generation. Specifically, Cu-doped ZnS photocatalysts integrated into a chitosan matrix, featuring internally aligned channels, not only facilitate mass transport but also significantly enhances the hydrogel's photochemical and electrokinetic properties. Dual functionality is attainted through the harmonious combination of light absorption, charge separation, and fluid transport features within a unified material system, embodying a balance between the photophysical reactions for hydrogen production and the capillary flow essential for electricity generation through the streaming potential phenomenon. Finally, the real-world environmental demonstration achieved a hydrogen generation rate of 17.3 mmol m-2 h-1 under natural sunlight irradiation and a potential output of 192.8 mV. Overall, this study demonstrates strategies applicable to designing other ambient energy harvesters with the potential to convert disparate renewable energy sources for sustainable energy production.