rGO‐CuO_x Composites Reduced by Solid‐Phase Microwave Thermal Shock for High‐Efficient Seawater Desalination and Purification

Abstract The solid‐phase microwave thermal shock (SMTS) strategy is a novel method to fabricate micro‐nano composites via interface engineering. By exploiting the transient hot spot effect and arc discharge of strong microwave absorbing materials, rGO‐CuO_x composites from GO‐Cu(OH)₂ precursors within several 10‐s cycles are synthesized. In the composites, Cu₂O nanoparticles show a narrow size distribution of 10–50 nm with metallic Cu nanoclusters uniformly distributed on the surface. The optimized sample exhibits excellent photothermal performance by coupling solar‐to‐thermal effects from phonons, free electrons, and electron acceptors. The seawater evaporation rate is 1.28 kg m^‐2 h^‐1 with 85.7% solar‐to‐vapor conversion efficiency under 1 sun radiation. Meanwhile, the composite evaporators are characterized by excellent anti‐salt and anti‐bacterial properties during the evaporation. The removal efficiency of Na⁺, Mg²⁺, K⁺, and Ca²⁺ is above 99.5%. These findings provide a sound basis for large‐scale desalination and purification of seawater.