Photocatalytic oxidation is a technology developed in recent years for the degradation of indoor air pollutants. In this study, magnesium cement-based photocatalytic material (MPM) was prepared by loading TiO₂ photocatalysts onto a SiO₂-modified basic magnesium chloride whisker (BMCW) surface, and was subsequently sprayed evenly on the surface of putty powder to form a photocatalytic functional wall coating (PFWC) material. Then, by introducing Ag, visible light photocatalytic functional wall coating (VPFWC) materials were also prepared. The results show that TiO₂ and SiO₂ form Ti–O–Si bonds on the BMCW surface, and the PFWC presents a promising degradation effect, with a photocatalytic removal rate of 46% for gaseous toluene, under ultraviolet light for 3 h, and an MPM coating concentration of 439 g/m². This is related to the surface structure of the functional coating, which is formed using putty powder and MPM. The visible light photocatalytic efficiency of the VPFWC increased as the spraying amount of the AgNO₃ solution increased, up to 16.62 g/m², and then decreased with further increasing. The gaseous toluene was degraded by 28% and 73% in 3 h, by the VPFWC, under visible light and ultraviolet light irradiation, respectively. In addition, the photocatalytic performance of the PFWC/VPFWC also showed excellent durability after being reused five times.

Porous magnesium oxychloride cement (PMOC) has a high specific surface area formed by interlocking whiskers, which can be used as a promising photocatalyst substrate for the photocatalytic removal of atmospheric pollutants. In this paper, magnesium oxychloride cement (MOC) was used as matrix and TiO₂ as catalyst to prepare MOC blocks. Plant-based protein was used as a foaming agent to form the layered porous structure suitable for supporting TiO₂ particles, which effectively increased the surface area of light radiation and TiO₂ adhesion area in photocatalytic porous magnesium oxychloride cement (PPMOC). It was found that the addition of the foaming agent can increase the adsorption capacity of MOC to TiO₂. The vacuum-immersion loading method can effectively support TiO₂ on the surface of PMOC. The photocatalytic performance of PPMOC can be improved by multiple loading, while higher porosity of PMOC would reduce the loading surface of matrix to TiO₂ particles, which might decrease the photocatalytic efficiency. As can be observed in PPMOC specimens, when the porosity of PPMOC is less than 60%, increasing the porosity can improve the photocatalytic efficiency, while when the porosity is higher than 60%, increasing the porosity decreased the photocatalytic efficiency due to the reduction of the loading surface. The excellent nitrate selectivity of PPMOC also shows good application potential in the field of catalytic degradation of nitrogen oxides.