MOF-based high-entropy-alloy evaporator featuring enhanced interband transitions for efficient solar steam and green electricity generation

Photothermal materials exhibiting broadband optical absorption and high energy efficiency are highly sought after in the field of solar-driven evaporation. Herein, we present a novel photothermal material derived from polymetallic metal–organic frameworks (MOFs) through a d-d interband transition (d-d IBT) engineering strategy. This approach enables comprehensive occupation of electronic states within ±4 eV relative to the Fermi level through 3d transition metal coordination, achieving an exceptional average solar absorption efficiency of over 97 % across the full solar spectrum (250–2500 nm). This breakthrough effectively overcomes the inherent wide bandgap limitation of MOFs that traditionally restricts their full-spectrum solar utilization. Leveraging its remarkable broadband sunlight harvesting capacity and ultrafast localized heating performance, this evaporator engineered with high-entropy alloy nanoparticles, achieves an evaporation efficiency surpassing 95% under one sun irradiation while maintaining a high evaporation rate of 2.80 kg m⁻² h⁻¹. Moreover, this evaporator demonstrates exceptional desalination efficiency even with high-salinity seawater (20 wt%), while the waste heat generated during operation can be strategically repurposed to produce green electricity, enhancing its sustainability profile. Thus, the FeCoNiMnCuAlZn high-entropy alloy nanoparticle-based photothermal evaporator offers innovative solutions for addressing the scarcity of clean water resources and the need for green energy.