A novel ternary Mica/TiO2/Fe2O3 composite pearlescent pigment for the photocatalytic degradation of acetaldehyde

A novel ternary mica/TiO2/Fe2O3 composite pearlescent pigment has been designed for the photocatalytic oxidation of gas-phase acetaldehyde in the application of indoor air purification. The mica/TiO2/Fe2O3-x (MTF-x, x = m(Fe2O3) : m(TiO2) = 0.5-2: 100) composites were synthesized by a sol-gel assisted hydrothermal method. The MTF-1.5 composite shows optimal photocatalytic performance, which is 1.8 times photodegradation efficiency and 2.2 times CO2 mineralization efficiency higher than those of pure TiO2. The enhanced photocatalytic performance of MTF-x (x = 0.5-2) composites could be associated with enhanced reflectivity of mica, which eventually improved the light absorption properties. Also, the presence of TiO2/Fe2O3 heterostructure facilitated charge separation in the MTF ternary composite. Besides, superoxide radical was proven as the decisive active species for the degradation of gaseous acetaldehyde. This work provides a systematic approach to develop a potential multi-functional pearlescent pigment to purify indoor air.