A novel water electrolysis hydrogen production system powered by a renewable hydrovoltaic power generator

Abstract

The acceleration of eco-friendly energy generation technologies has been driven by pressing environmental issues such as global warming. Among the promising approaches is electricity generation from infinite moisture. Water evaporation-based power generation has garnered significant attention due to its capability for continuous power generation. However, existing devices face challenges in maintaining long-term generation and producing sufficient voltage and current. In this study, we introduce a cellulose sponge-based hydrovoltaic power generator (CHPG) as a power source for hydrogen production. A single CHPG (3.0 × 1.0 × 0.7 cm3) achieves an open-circuit voltage of approximately 0.47 V and a short-circuit current of approximately 477 μA under relative humidity of 45–50 % at 25 °C. To enhance water electrolysis for hydrogen production, we optimized and scaled up the CHPGs into modules (six CHPGs in series) and packages (six CHPG modules in parallel). Consequently, the generator with three packages connected in parallel produces 2.09 V and 3.11 mA. This configuration enabled hydrogen gas generation at a rate of 81.0 μmol h−1 from the electrode. This study lays the groundwork for future research aimed at hydrogen gas production through hydrovoltaic electricity. © 2024 Elsevier B.V.