(BiO)₂CO₃ hierarchical microspheres and (BiO)₂CO₃ nanoparticles with wide band-gaps were fabricated by a simple hydrothermal method. The former showed higher visible light photocatalytic activity towards the removal of NO than the latter due to the enhanced extrinsic absorption benefiting from the strong light reflecting and scattering effects. The extrinsic absorption over (BiO)₂CO₃ hierarchical microspheres can induce the production of holes and electrons with visible light, subsequently generating active species to participate in photocatalytic reactions.