Optimisation of Laser-Synthesized Heterostructured Multielement Nanoparticles for Solar Steam Generation and Water Purification

The sustainable production of clean water is one major objective for both developing and industrialized regions. Nanoheterostructures offer synergistic optical and interfacial functionalities for water purification, yet their optimization against desired functions and sustainable synthesis protocols remains challenging. Here, we integrate design-of-experiments with laser ablation in liquids (LAL) to optimize multielement Fe–Mn–B nanoparticles (NPs) for interfacial solar steam generation and water purification. Multiobjective optimization identified a B-rich Fe10Mn24B66 LAL target composition as the Pareto-optimal region, and experimental validation further revealed that laser ablation in acetone produces a compositionally heterogeneous Fe/Mn/B@C nanoarchitecture with the highest photothermal output. When deposited onto cellulose support, the optimized NPs deliver an evaporation rate of 2.40 ± 0.05 kg·m–2·h–1 at 3.5 suns. Translation to electrospun nanofiber membranes enables >5× area scale-up without loss of evaporation rate, providing 0.56 ± 0.02 kg·m–2·h–1 under 1 sun, with a >6-fold enhancement relative to the membrane alone. The evaporator maintains desalination performance for 5–10 wt % NaCl brine and efficiently removes organic dyes and trace PFAS (PFOA), yielding low-conductivity, contaminant-free condensate. Finally, scenario-based life-cycle assessment identified electricity as the dominant hotspot at laboratory throughput and mapped a plausible pathway toward lower footprints as productivity and downstream manufacturing are improved.