Remote-controlled saline tolerant tough-yet-strong solar vapor evaporator based on multifunctional Fe3O4 nanoparticle reinforced gel-nacre

Solar vapor evaporators in saline hold enormous potentials in resource sustainability, seawater desalination, as well as renewable energy harvesting. Nanocomposite hydrogels with the property of photothermal conversion have emerged as candidates for solar-driven steam generation devices, but are limited by remote control and low mechanical properties in a saline environment. Here, we developed a remote-controlled, saline tolerant, and tough-yet-strong solar vapor evaporator based on multifunctional Fe3O4 nanoparticle reinforced gel-nacre. The Fe3O4 nanoparticles play triple roles of acting as nano-crosslinks, photothermal converters, and untethered manipulation, coupling gel-nacre matrix with a shrinking tendency in saline that contributes to synergistic mechanical reinforcement. Such integrated magnetic nanocomposite hydrogel exhibits tough-yet-strong mechanical properties (19.58 MPa ultimate strength, 300 % failure strain, self-recoverability under 500 %, and fatigue-resistance), addressing the challenges of remote operation system and high strength requirement for practical applications. Moreover, good photothermal conversion performances (1.26 kg m−2 h−1 evaporation rate and 92.84 % evaporation efficiency) could be achieved with remotely controlled motion or adjustable position simultaneously under an external magnetic field. The intelligent solar vapor evaporation system based on multifunctional magnetic Fe3O4@gel-nacre nanocomposite provides new opportunities for flexible energy-transducing devices with untethered manipulation in saline environment.