Nanoscaled Bi2O4 confined in firework-shaped TiO2 microspheres with enhanced visible light photocatalytic performance

Bi2O4 is a newly found semiconductor photocatalyst with visible-light response property; however, due to its large particle size, the photocatalytic efficiency is greatly limited. Reducing the particle size down to nanoscale is an efficient way to enhance the photocatalytic ability, but still challenging. Herein, the firework-shaped hierarchical TiO2 microsphere was used as the framework to spatially confine the growth of Bi2O4. SEM characterization results reveal nanosized Bi2O4 particles are successfully inserted into the TiO2 microsphere, forming enormous Bi2O4/TiO2 heterojunctions. Benefitted from the nanoscaled Bi(2)O(4 )and the formation of Bi2O4/TiO2 type II heterojunction, both the separation efficiency of charge carriers and the quantum yield are improved. As a result,Bi2O4/TiO2 heterojunctions show much higher photocatalytic activity than that of pristine Bi2O4 in the degradation of methyl orange and tetracycline under visible light. Radical capture experimental results imply that hole is the dominant reactive species for the degradation of methyl orange. The present work paves the way for designing nanosized photocatalyst via the space-confined effect.