Fabrication of 2H/3C-SiC heterophase junction nanocages for enhancing photocatalytic CO2 reduction.

The morphology and structure of photocatalyst play an important role in photocatalytic activity. SiC semiconductor is considered as a promising material for the photocatalytic CO2 reduction due to its negative conduction band position. Herein, SiC nanocages is creatively synthesized by simple low-temperature molten-salt-mediated magnesiothermic reduction method with using SiO2 as template. The morphology and phase composition of SiC nanocages can be controlled by magnesium dosage and reaction temperature. The 2H and 3C crystal phase in SiC nanocage can form heterophase junctions uniformly to effectively accelerate the photogenerated electron transfer, and plays a key role in improving the photocatalytic activity of 2H/3C-SiC samples. The optimal SiC nanocage sample possesses a CO generation rate of 4.68 μmol g-1h-1 for photocatalytic CO2 reduction, which is 3.25 times higher than that of commercial SiC.