Multifunctional plasmonic Ag–Cu alloy nanoparticles immobilized on reduced graphene oxide for simultaneous solar-driven steam, wastewater purification, and electricity generation

Abstract

Solar-driven water evaporation is crucial for drinkable water production using cost-effective solar energy and has recently gained more interest through the improvement of heat localization strategies. However, the original water sources may contain oil impurities and other organic pollutants that seriously impair the evaporation process and pose environmental hazards. Here, we developed a multifunctional nanocomposite Ag, Cu-rGO for the production of clean water by simultaneous photocatalysis, oil resistance, adsorption, and water evaporation powered by the sun. The phonon-assisted relaxation process under solar irradiation was effectively accelerated by the incorporation of rGO by Ag and CuNPs alloy, which can alter the bandgap and introduce a significant number of intermediate band (IB) states. We demonstrate that by employing the Ag, Cu-rGO evaporator under solar light irradiation, a high-water evaporation rate of 1.89 kg m−2 h−1 with a high solar-to-heat conversion efficiency of 90.2% can be accomplished. Additionally, the membrane can concurrently purify the raw water during solar evaporation by organic dye degradation, heavy metals adsorption, oil resistance, and pathogenic bacteria disinfection. Meanwhile, the heat dissipation to the bulk water can be recovered by the conversion to electricity using a commercial TE-module which simultaneously generates voltage generation of 17.3 mV with a power density of 5.72 W m−2. For solar-driven water evaporation from multiple sources, such an all-in-one multifunctional membrane is an excellent candidate.

Keywords

• Solar-driven water evaporation
• Alloying
• Disinfection
• Photodegradation
• Electricity generation
• Oil-resistance