Graphitic carbon nitride (g-CN) has attracted tremendous attention as visible-light photocatalyst. However, for further improving the catalytic activity, multilevel and hierarchical nanostructuring of g-CN is highly desirable to effectively expose active sites and facilitate separation and migration of photoexciteded charge carriers for largely enhanced photocatalytic behavior. Here, we prepare wall-mesoporous graphitic carbon nitride nanotubes (g-CNNTs) by in situ annealing of urea microrod arrays preformed in virtue of a vertical gradient freeze growth (VGFG) method. Benefiting from the distinctive structural features, the hierarchical g-CNNTs exhibit a high photocatalytic H2 production rate of 8789 μmol h-1 g-1 with an excellent apparent quantum yield of 6.3 % under visible-light irradiation and long-term cycling stability. This work provides a facile and eco-friendly strategy to prepare a new type of carbon nitride-based nanostructural material for photocatalysis and environmental remediation.
Keywords: graphitic carbon nitrides; hydrogen evolution; mesoporous nanotubes; photocatalysis; urea microrod arrays; vertical gradient freeze growth.
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