Wall‐Mesoporous Graphitic Carbon Nitride Nanotubes for Efficient Photocatalytic Hydrogen Evolution

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 H 2 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.