Defect-rich Mg(OH)₂ nanosheets as high-performance antioxidants

The development of highly efficient radical scavengers remains a substantial challenge in materials chemistry. Here, we report defect-rich Mg(OH)₂ nanosheets (d-Mg(OH)₂), synthesized via rapid nucleation within a colloid mill, as a potent multifunctional antioxidant. Compared to commercial Mg(OH)₂ (c-Mg(OH)₂), d-Mg(OH)₂ demonstrates markedly superior scavenging capabilities against a broad spectrum of radicals, including ·O₂⁻, ·OH, ·NO, DPPH·, and ·Cl. Mechanistic investigations and density functional theory calculations reveal a dual-mode scavenging mechanism: hydrogen atom transfer for ·OH, ·NO, and ·Cl, and electron transfer for ·O₂⁻ and DPPH·, with significantly reduced energy barriers on the defect-rich surface. We further demonstrate the material’s practical efficacy in scavenging intracellular reactive oxygen species and enhancing the thermal stability of polyvinyl chloride. This work establishes a defect-engineering approach to activate earth-abundant hydroxides as high-performance antioxidants, with promising applications in biomedicine and polymer stabilization.