Self-cleaning MOC fabricated from dolomite ore

Abstract This study explores the sustainable synthesis of magnesium oxychloride cement (MOC) using reactive MgO derived from dolomite, coupled with photocatalytic and supplementary cementitious materials (SCMs) to optimize both mechanical and self-cleaning performance. The synthesis of MgO from dolomite was performed using a fractional design of experiments 2⁵⁻¹ to identify the main factors that affect the purity and the surface area of the powders. The analysis of the design of experiments revealed that acid treatment temperature and reaction time during MgO synthesis significantly influenced surface area and MgO content. After the identification of the best conditions to synthesize a high-purity MgO from dolomite, a series of MOC formulations were prepared by incorporating TiO₂, fly ash, and slag. The physicochemical, optical, mechanical, and photocatalytic properties of the resulting composites were systematically investigated. TiO₂ incorporation clearly enhanced light absorption, while combinations with slag or fly ash modulated this property, which is an important property for photocatalytic self-cleaning applications. In photocatalytic assays under simulated sunlight, TiO₂-containing cements outperformed the unmodified MOC, with fly ash–based formulations achieving the highest self-cleaning efficiency. Blended systems with SCMs introduced trade-offs between durability and functionality, with photocatalyst nanoparticles achieving an optimal balance, showing excellent moisture stability and photocatalytic performance (> 92%) under sunlight irradiation. These results highlight the potential of combining alternative MgO sources with functional additives to engineer eco-efficient, durable, and photocatalytically active MOC materials for advanced construction applications.