Biomass-derived 3D evaporator with antifouling and salt-rejecting toward solar-enabled steam generation, desalination, and electricity generation

Solar-driven interfacial evaporation is currently considered as one of the most effective and sustainable strategies to address water scarcity and energy shortages issues. Whereas, challenges in developing durable, eco-friendly, and low-cost solar evaporators from readily available materials still exist. Herein, we have reported a facile strategy to construct a robust natural sorghum stalk pith solar evaporator. With advantageous features of gradient honeycomb structure and hydrophilic polymer chains, the constructed evaporator exhibits broadband light absorption, efficient light to heat conversion, fast water transport, and multi-channel release of steam performances, leading to an ultrahigh evaporation rate of 3.79 kg m−2h−1 under one sun irradiation and outstanding salt-resistant ability at a high evaporation rate of 2.6 kg·m−2·h−1 in a highly concentrated brine (20 wt% NaCl), accompanied with anti-oil-fouling performances, as well as high oil removal efficiency (>99.8 %) for oil-in-water emulsion, outperforming most previously reported solar evaporators. Additionally, solar irradiation can further promote the directional water flow, contributing to a high photovoltage of 68 mV under one sun illumination. This paves the way for designing durable biomass-based steam generators, not only scaling up sustainable clean water production, sewage depuration and desalination, but also discovering promising application in the field of electricity generation.