Photothermal and Joule Heating for Interfacial Evaporation: Synergy through Nanomaterial Incorporation in Laser-Induced Graphene

Graphene and its derivatives have been used for various applications, including water production and decontamination. Interfacial evaporation-based water generation is a potential application of photo- and electrothermal materials. Laser-induced graphene (LIG) is a facile, low-cost, single-step process to fabricate graphene on carbonaceous substrates. Incorporating nanomaterials further enhances the photothermal and electrothermal properties of LIG surfaces. In this research, we explored the effect of different metal and metal-oxide nanomaterials of titanium (Magnéli phase), copper, and iron incorporation in LIG-nanomaterial composites and their impact on electro- and photothermal performance for interfacial evaporation-based water treatment. Composite LIGs achieved high evaporation rates up to ∼2.5 kg m–2 h–1 while driven by solar energy and ∼1 kg m–2 h–1 with a Joule heating setup. LIG composite containing conductive metal suboxides of titanium exhibited the highest performance improvement of ∼300% higher compared to pristine and other LIG composites. These LIG-based interfacial evaporators showed a fast on-and-off response for speedy clean water production. In stacked configurations, these metal–LIG composite surfaces offer a promising source of decontaminated water for various applications. This work demonstrated a potential and scalable application of LIG evaporators to address desalination and wastewater-treatment challenges with a reduced carbon footprint, promoting sustainability.