Sustainable Fuel Production from Ambient Moisture via Ferroelectrically Driven MoS₂ Nanosheets

Abstract Unlike traditional water splitting in an aqueous medium, direct decomposition of atmospheric water is a promising way to simultaneously dehumidify the living space and generate power. Here, a tailored superhygroscopic hydrogel, a catalyst, and a solar cell are integrated into a humidity digester that can break down ambient moisture into hydrogen and oxygen, creating an efficient electrochemical cell. The function of the hydrogel is to harvest moisture from ambient humidity and transfer the collected water to the catalyst. Barium titanate and vertical 2D MoS₂ nanosheets are integrated as the catalyst: the negatively polarized cathode can enhance the electron transport and attract H⁺ to the MoS₂ surface for water reduction, while water oxidation takes place at the positively polarized anode. By employing this mechanism, it is possible to maintain the relative humidity in a medium‐sized room at <60% without any additional energy input, and a stable current of 12.5 mA cm⁻² is generated by the humidity digester when exposed to ambient light.