A novel ternary mica-titania@rGO composite pearlescent pigment for the photocatalytic degradation of gaseous acetaldehyde

Abstract

The photocatalytic application of TiO2 is limited due to low light harvesting abilities in the whole solar spectrum and fast recombination of the photoinduced electron-hole pairs. Herein, we report a TiO2-based ternary composite photocatalyst (MT@rGO-x; x = 0.05–0.2) with a pearlescent color effect, which incorporates a mica reflection core and a rGO multifunctional shell as cocatalysts. The micro flake composites were synthesized by a facile precipitation route and applied first to photodegrade gaseous acetaldehyde. MT@rGO-0.1 composite has optimal performance, which is 2.5 times photodegradation efficiency and 3 times CO2 mineralization efficiency higher than those of pure TiO2. The enhanced photocatalytic performance of MT@rGO composite is associated with effectively improved light harvesting of TiO2 by mica reflection. The presence of rGO facilitates the separation of electron-hole pairs and pollutant absorption. In addition, the superoxide radical was proved as the decisive active species for the photodegradation of acetaldehyde by electron spin resonance analyses and radical quenching tests. Our MT@rGO photocatalyst is expected to be applied as a functional and decorative additive of car paint, which is subject to photodegradation due to air pollutants.