Solar steam generation is an emerging technique that harvests intermittent sustainable solar energy for large-scale wastewater purification and desalination. However, the application of solar steam generators is currently restricted by their high cost and low solar-thermal conversion efficiency. Herein, we demonstrate a highly efficient, portable, low cost and reusable interfacial solar evaporator fabricated using three-dimensional (3D) printing technology. Using cues from nature, the 3D-printed honeycomb lightweight evaporators are designed to have microporous capillary channels, which facilitate water transportation for continuous solar steam generation. The graphene coating on the surface enables efficient solar-to-vapor energy transfer, and a thermally insulating photopolymer suppresses heat loss. The optimized 3D-printed solar evaporator thus has a rapid evaporation rate of 2.67 kg m⁻² h⁻¹ (normalized to the projection area) and a high apparent solar-to-heat efficiency of 178.5% under 1 sun irradiation. The device shows outstanding antifouling properties and hence has wide application prospects for long-term domestic wastewater reduction and desalination of high-salinity brine.

The influences of processing parameters such as volumetric energy density (ε) and, particularly, defocusing amount (DA) on densification, microstructure, tensile property, and hardness of the as-printed dense AlSi10Mg alloy by selective laser melting (SLM) were studied systematically. The molten pool boundaries (MPBs) were found overwhelmingly at regular and complex spatial topological structures affected by DA value to exist in two forms, while the “layer–layer” MPB overlay mutually and the “track–track” MPBs intersect to form acute angles with each other. The microstructure of MPBs exhibits a coarse grain zone near the MPBs and the characteristics of segregation of nonmetallic elements (O, Si) where the crack easily happened. The DA value (−2 to 2 mm) affected both the density and the tensile mechanical properties. High tensile strength (456 ± 14 MPa) and good tensile ductility (9.5 ± 1.4%) were achieved in the as-printed condition corresponding to DA = 0.5 mm. The tensile fracture surface features were analyzed and correlated to the influence of the DA values.