Bis‐Quaternary Ammonium Surfactants‐Assisted Growth of MgO Nanostructures for Water Pollution Mitigation

Abstract This work explores the synthesis of magnesium oxide (MgO) nanostructures using the facile hydrothermal method, employing bis‐quaternary ammonium surfactants as shape and size directing agents. These specific surfactants are essential in structuring the nanostructures, for (12‐2‐12)‐MgO they provided anisotropic sharp‐edged nanostructures with an average size of ≈19 nm, and spherical nanoparticles with an average size of ≈53 nm for (14‐2‐14)‐MgO nanoparticles. To determine the crystalline size and lattice strain, an intensive structural investigation is carried out employing the Williamson‐Hall (W‐H) analysis. With an optical band gap value of 2.90 eV and significant quantum confinement effects, the (12‐2‐12)‐stabilized MgO nanostructures demonstrated remarkable photocatalytic efficacy in visible light degradation of organic pollutants, attaining a 96% degradation rate. In contrast, a 91% degradation rate is shown by the (14‐2‐14)‐stabilized MgO nanoparticles, with a band gap of 2.74 eV. Furthermore, the calculated conductivity values are determined for (12‐2‐12)‐MgO and (14‐2‐14)‐MgO nanostructures, varied from 7.3 to 11.61 S cm ⁻¹ and 5.6 to 9.2 S cm ⁻¹ , respectively. Owing to the greater surface‐to‐volume ratio and quantum confinement effect, (12‐2‐12)‐MgO has a higher electrical conductivity. These MgO nanostructures have significant potential for environmental applications, particularly in mitigating water pollution, as evidenced by their excellent photocatalytic performance and simple fabrication methods.