Graphitic Carbon Nitride Microtubes for Efficient Photocatalytic Overall Water Splitting: The Morphology Derived Electrical Field Enhancement

The hollow morphology of photocatalysts significantly affects the light absorption, scattering, and charge separation ability. However, the mechanism that dictates the interaction between the light scattering and its modulation on electrical field for enhanced photocatalytic activity is not well understood hitherto. Herein, we investigate such a unique characteristic by designing three carbon nitride photocatalysts, e.g., graphitic carbon nitride microtubes (TCN), phosphorus-doped carbon nitride microrods (PCN), and bulk g-C3N4. The as-derived TCN exhibits 31 times higher photocatalytic activity in overall water splitting than pristine g-C3N4, which produces H-2 and O-2 at the reaction rates of 110.3 and 44.7 mu mol h(-1) g(-1), respectively. The enhanced catalytic performance is attributed to the enhancement in electrical field, as evidenced by the improved charge separation and the finite element modeling simulation. Contributions from the specific surface area and band structure are also discussed. Unveiling the relationship between morphology and electrical field is expected to guide the rational design of morphology-oriented photocatalyst for highly efficient water splitting.