The global water-scarcity crisis, exacerbated by population growth and pollution, necessitates the securing of freshwater resources. Recently, interfacial solar steam generation (ISSG) has emerged as a promising and cost-effective seawater-desalination technology with minimal secondary contamination. However, it employs high-end materials and complex structures, limiting its practical applicability. We develop an advanced diatomite evaporator (ADE) by incorporating inexpensive porous materials, such as diatomite, natural cement, and graphene nanoplatelets, which are readily available and replicable. To maximize evaporation efficiency while minimizing energy utilization, the structural density of the ADE is optimized during fabrication. Capillary-rise and geometric-modification experiments show that heat loss increases with temperature as the ADE diameter increases and the evaporation rate above a particular height saturates because of insufficient water supply. The optimal aspect ratio (height/diameter) of the ADE is approximately 4.8, with an evaporation rate of approximately 6.30 kg m−2h−1. Through the optimization of composition density and viscosity in the diatomite-cement dough, ADE achieved superior mechanical strength and durability, offering significant advantages for long-term and repeated use. The proposed ADE sustains evaporation performance for > 16 h and maintains stability after 10 repeated desalination cycles. This study will contribute to the development of a cost-effective and practical ISSG technology.
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