Fabrication of g-C3N4/TiO2 hierarchical spheres with reactive {001} TiO2 crystal facets and its visible-light photocatalytic activity

• First report about the g-C3N4/{001}TiO2 hierarchical spheres.
• The photoactivity of as synthesised samples was fully evaluated.
• The g-C3N4/TiO2 composites exhibit superior visible-light photocatalytic activity.
• The mechanism of enhanced photocatalytic activity has been proposed.

Graphitic carbon nitride (g-C3N4) is a fascinating polymeric organic semiconductor and has attracted extensive interests from researchers during the past few decades. This work focused on a g-C3N4/TiO2 composite with high percentage of {001} facets. We confirmed that composites of g-C3N4/TiO2 with close interfacial connections between g-C3N4 and TiO2 had been formed and made up of reactive {001} TiO2 crystal facets. It also presented significantly enhanced photocatalytic ability toward to RhB degradation, gaseous acetone photoconversion and hydrogen evolution under visible light irradiation. Active species trapping experiments indicated that O2− played a most important part in catalytic process. It was also pointed out that the enhanced photocatalytic efficiency could be attributed to the interfacial connections between g-C3N4 and TiO2, which efficiently transferred the photocarriers.