Functionalized Al₂O₃-Based 3D Hydrovoltaic Device: Harnessing Electricity from Water Evaporation

Electricity generation from water evaporation, known as the hydrovoltaic phenomenon, has drawn widespread attention due to its green-energy-based power production. However, inferior power output, complex fabrication process, and high cost compared to those of other renewable energy devices limit its commercialization. A slower evaporation rate of water and insufficient charge collection at the electrode surface are the major fundamental setbacks that limit the power output. Herein, we report a simple and effective three-dimensional (3D) tubular hydrovoltaic device based on porous Al2O3 nanoparticles. This device exhibited a higher evaporation rate due to higher hydrophilicity and improved charge collection and transport in the hydrovoltaic device. A single device generated an open-circuit voltage (Voc) of 1.08 V, and a short-circuit current (Jsc) of 80 μA with a maximum power output of 12 μW. The accumulated output energy can be used by employing series and parallel combinations to meet the practical needs of powering electronic devices. This device also demonstrated a facile electrochemical dye degradation of methylene blue (MB) using the current and voltage developed from an ecofriendly Al2O3 hydrovoltaic device. Thus, this work provides an important reference that contributes significantly to the practical implementation of clean energy.