Self‐Contained Monolithic Carbon Sponges for Solar‐Driven Interfacial Water Evaporation Distillation and Electricity Generation

TLDR

Solar vaporization is attractive for desalination, sterilization, and distillation, yet its practical deployment is limited by high cost, fragility, and low efficiency of current solar absorbers. The study reports an inexpensive cellular carbon sponge with broadband light absorption and built‑in structural features that localize heat for in‑situ photothermic vaporization. Its elastic, porous structure self‑confines water at hot spots and tolerates cyclic fluid‑flow stresses, enabling practical operation. The sponge delivers a 2.5‑fold increase in solar‑to‑vapor efficiency over bulk heating while harvesting electricity from steam, presenting a dual solution for remote water and power generation.

Abstract

Abstract Solar vaporization has received tremendous attention for its potential in desalination, sterilization, distillation, etc. However, a few major roadblocks toward practical application are the high cost, process intensive, fragility of solar absorber materials, and low efficiency. Herein an inexpensive cellular carbon sponge that has a broadband light absorption and inbuilt structural features to perform solitary heat localization for in situ photothermic vaporization is reported. The defining advantages of elastic cellular porous sponge are that it self‐confines water to the perpetually hot spots and accommodates cyclical dynamic fluid flow‐volume variable stress for practical usage. By isolating from bulk water, the solar‐to‐vapor conversion efficiency is increased by 2.5‐fold, surpassing that of conventional bulk heating. Notably, complementary solar steam generation‐induced electricity can be harvested during the solar vaporization so as to capitalize on waste heat. Such solar distillation and waste heat‐to‐electricity generation functions may provide potential opportunities for on‐site electricity and fresh water production for remote areas/emergency needs.