Nanosecond Laser Patterned Porous Graphene from Monolithic Mesoporous Carbon for High‐Performance Solar Thermal Interfacial Evaporation

Abstract Photothermal interfacial evaporation based on micro‐nano porous materials is an effective and energy‐saving new strategy to utilize low‐density solar energy to achieve water purification, but there are still many challenges especially in preparing nanostructures toward enhanced performances. Here, a one‐step simple method is adopted by using nanosecond laser to process the surface of monolithic biomass carbon under ambient conditions. During the preparation process, the surface of biomass carbon is directly converted into patterned porous graphene under the action of nanosecond laser. This method not only provides a new way for the wide and easy preparation of graphene, but more importantly, it can be very convenient to prepare graphene‐biomass porous carbon composites with special textures and special microstructures with ultra‐broadband light absorption. The combination of the macroscopic porous feature in monolithic carbon revealed by synchrotron X‐ray ptychography together with the nanostructured surface of patterned porous graphene demonstrates ultrahigh solar thermal‐vapor conversion rate up to 98.7%. This work develops an effective way to fabricate porous graphene from biomass carbon, as well as an energy‐efficient water treatment technology toward wastewater containing complex contaminants.