Facet-controlled synthesis of polyhedral hematite/carbon composites with enhanced photoactivity

摘要

Much effort has been made to develop the semiconductor photocatalysis, but it is still challenging to fabricate low-cost and high-activity photocatalysts. In this study, Hematite (alpha-Fe2O3) with three kinds of morphologies including dodecahedron, tetrakaidecahedron and hexagonal nanoplates have been synthesized without any organic reagents. The photocatalytic performance reveals that the dodecahedron with exposed {1 0 1} facets is superior to the hexagonal nanoplates with predominant exposure of {0 0 1} facets in the case of similar BET surface area. For further enhancement of photocatalytic activity, carbon layer was coated on dodecahedral alpha-Fe2O3 through the self-polymerization of dopamine and following pyrolysis at 400 degrees C under Ar flow. Compared with the pristine dodecahedral alpha-Fe2O3, the alpha-Fe2O3/C composites exhibit stronger visible absorption, lower photoexcited electron-hole pairs recombination rate and better photodegradation activity. The photocatalytic performance showed the degradation rate of alpha-Fe2O3-D/4.5C is nearly 6 times higher than pristine alpha-Fe2O3, which have great potential for photocatalysis applications. (C) 2018 Elsevier B.V. All rights reserved.