Enhancing the performance of molybdenum disulfide-based solar water evaporation systems by tuning the synthesis temperature

Abstract

MoS₂ has been developed for use in solar water evaporation systems. Studies have shown that the temperature and duration of synthesis significantly affect the phase, number of layer, and particle size of MoS₂. However, there is a lack of comprehensive research on how these factors, including the wettability of MoS₂, influence the water evaporation rate. In this study, we synthesized MoS₂ at two distinct temperatures: 180 and 200°C using a hydrothermal method. This study shows MoS₂ synthesized at 180°C forms smaller 2H-MoS₂ nanosheets with small grains size and more defects and exhibits higher evaporation rates $1.52\pm 0.02$ kg m⁻² h⁻¹. This increased evaporation is due to smaller nanosheets provides a larger surface area, enhancing light absorption and thermal energy conversion. The defective sites in MoS₂, especially along its edges, act as preferential adsorption sites for water molecules. This facilitates water diffusion, and consequently increases wettability and accelerates evaporation. The use of MoS₂ on air-laid paper as photothermal materials also demonstrated excellent salt rejection (>99%). This work demonstrates the novelty of tuning the efficiency of MoS₂-based solar water evaporation systems by simply adjusting the synthesis temperature. This approach is an innovative method for industrial-scale solar evaporation applications.