Mechanistic insights of facile synthesized-solar driven TiO₂ intercalated 2D molybdenum disulfide evaporator for one-pot clean water production

Rising water pollution and increasing demand for water have caused a global freshwater shortage, leading to serious health issues and slowing development. Since seawater constitutes about 97.5 % of the Earth's water, desalination is essential to solve this crisis. Solar water evaporation technology, which utilizes photothermal materials, is considered one of the most sustainable and crucial solutions for clean water production and addressing freshwater scarcity. However, photothermal materials are limited by their high preparation costs, low evaporation efficiency, and poor photothermal conversion. MoS₂ is a promising material with high solar to thermal conversion, but it suffers from poor thermal stability, limited active surface area, and agglomeration, which reduces its performance. To address these limitations, this study synthesized a high-performance photothermal titanium dioxide (TiO₂) intercalated two-dimensional (2D) molybdenum disulfide (MoS₂) composite via a hydrothermal method to increase the MoS₂ active surface area with high thermal stability TiO_2, which can improve the solar thermal conversion. The TiO₂-MoS₂ solar evaporator was constructed by attaching coated filter paper to polystyrene (PS) foam for structural support and thermal insulation, which enabled a heat localization effect. In contrast, a cotton wool positioned at the center of the filter paper facilitated water transport. This solar evaporator showed excellent photothermal efficiency (93.8 %) under standard sunlight intensity of 1.0 sun (1 kW‧m⁻²). The high evaporation rate achieved (1.22 kg‧m⁻²‧h⁻¹) was four times greater than that of a bare solar evaporator (0.3 kg‧m⁻²‧h⁻¹) with a 35 g‧L⁻¹ NaCl feed solution. This enhancement is attributed to improved morphological and photothermal properties, where TiO₂ stabilized MoS₂, prevented agglomeration, increased active surface area, and enhanced light absorption, enabling an efficient one-pot clean water production process. Therefore, this study presents a simple method for fabricating a solar evaporator with high energy efficiency and water evaporation capabilities in seawater desalination.