The physicochemical changes of magnesium oxide (MgO) by different preparation methods have been extensively explored for various applications; however, few studies have been conducted on the morphology and physicochemical properties of MgO controlled by various ageing conditions even though an ageing step is one of the important steps in the precipitation. In this study, morphological transformation of MgO was achieved by controlling the ageing time at different temperatures and the unusual transformation was observed; Microsphere-structured MgO, known to be unstable at low temperatures, could be formed even at 25 °C, owing to the abundant amount of OH⁻. In addition, the surface basicity was significantly affected by the aging conditions. Ageing at 60 °C furnished stronger basic sites on MgO, which resulted from the abundant oxygen vacancies. Notably, an unusual peak in the sample prepared at 80 °C of aging temperature was observed at 656 °C in the CO₂ temperature-programmed desorption profile, and it was attributed to the desorption of strongly adsorbed hydroxyl groups. The surface area was maximized (350 m² g⁻¹) by employing the ageing temperature of 80 °C, and the CO₂ sorption capacities of as-prepared samples were 6–7 wt.% during adsorption for 120 min at 25 °C. Understanding the physicochemical properties and basicity of MgO can facilitate the design of adsorbents or catalysts as a platform material.

氧化镁（MgO）通过不同的制备方法的理化变化已被广泛地研究用于各种应用。然而，尽管老化步骤是沉淀过程中的重要步骤之一，但对于由各种老化条件控制的MgO的形态和理化性质的研究很少。本研究通过控制不同温度下的时效时间实现了MgO的形态转变，并观察到了异常转变。微球结构的MgO，已知是在低温下不稳定的，甚至在25℃下形成，由于丰富量的OH ^-。此外，表面碱性会受到老化条件的显着影响。在60°C时效，由于大量的氧空位，使MgO上的碱位更强。值得注意的是，在CO ₂温度编程的脱附曲线中，在656°C的老化温度下，在80°C的老化温度下制备的样品中观察到一个不寻常的峰，这归因于强吸附羟基的脱附。通过使用80°C的时效温度和CO ₂使表面积最大（350 m ² g ^-1）在25°C的温度下吸附120分钟期间，制得的样品的吸附容量为6–7 wt。％。了解MgO的物理化学性质和碱度可以促进吸附剂或催化剂作为平台材料的设计。