Bio-inspired cracked metal-phenolic networks with durable confinement capillarity and photocatalysis for highly efficient evaporation and water remediation

Confinement capillarity based on functional coatings is an effective way to enhance water evaporation via generating thin water in the internal surfaces of porous photothermal materials. However, current functional coatings with confinement capillarity tend to be single-functional and easily detach from the substrates under mechanical compression, limiting their practical applications. Endowing evaporator with both durable confinement capillarity and versatility is still a great challenge due to the trade-offs among functional designs. Herein, inspired by nature, multifunctional cracked metal-phenolic networks (MC-MPNs) with durable confinement capillarity and photocatalysis are developed, which can be firmly decorated on porous sponges to fabricate high-performance and multifunctional evaporators. The crack patterns and surface microstructures of the MC-MPNs can be controlled, which not only generates an ultrathin water layer in the internal pores of a sponge to realize confinement capillarity, but also optimizes its photocatalysis properties. Therefore, the resultant evaporator can realize highly efficient evaporation (3.2 kg m−2 h−1) and dye photocatalysis without requiring H2O2 addition. Moreover, the cracks can act as a buffer zone to significantly enhance the stability of the MC-MPNs coatings under compression (negligible performance loss after 1000 cycles), breaking the bottleneck for the practical applications of confinement capillarity toward solar desalination and water remediation. This study will open an avenue to design multifunctional photothermal coatings with durable confinement capillarity, paving the way for their practical application in solar desalination and water remediation.