Improved Photo‐Excited Carriers Transportation of WS₂‐O‐Doped‐Graphene Heterostructures for Solar Steam Generation

Abstract Two‐dimensional (2D) transition metal dichalcogenides and graphene have revealed promising applications in optoelectronic and energy storage and conversion. However, there are rare reports of modifying the light‐to‐heat transformation via preparing their heterostructures for solar steam generation. In this work, commercial WS₂ and sucrose are utilized as precursors to produce 2D WS₂‐O‐doped‐graphene heterostructures (WS₂‐O‐graphene) for solar water evaporation. The WS₂‐O‐graphene evaporators demonstrate excellent average water evaporation rate (2.11 kg m⁻² h⁻¹) and energy efficiency (82.2%), which are 1.3‐ and 1.2‐fold higher than WS₂ and O‐doped graphene‐based evaporators, respectively. Furthermore, for the real seawater with different pH values (pH 1 and 12) and rhodamine B pollutants, the WS₂‐O‐graphene evaporators show great average evaporation rates (≈2.08 and 2.09 kg m⁻² h⁻¹, respectively) for producing freshwater with an extremely low‐grade of dye residual and nearly neutral pH values. More interestingly, due to the self‐storage water ability of WS₂‐O‐graphene evaporators, water evaporation can be implemented without the presence of bulk water. As a result, the evaporation rate reaches 3.23 kg m⁻² h⁻¹, which is ≈1.5 times higher than the regular solar water evaporation system. This work provides a new approach for preparing 2D transition metal dichalcogenides and graphene heterostructures for efficient solar water evaporation.