In Situ Phase-Induced Spatial Charge Separation in Core–Shell Oxynitride Nanocube Heterojunctions Realizing Robust Solar Water Splitting

5 years ago

In Situ Phase-Induced Spatial Charge Separation in Core–Shell Oxynitride Nanocube Heterojunctions Realizing Robust Solar Water Splitting

Zheshuai Lin, Licheng Sun, Zhanming Gao, Fei Liang, Shuyan Cao, Yunzhen Wu, Jungang Hou

Efficient spatial charge separation is critical for solar energy conversion over solid photocatalysts. The development of efficient visible-light photocatalysts has been of immense interest, but with limited success. Here, multiband core–shell oxynitride nanocube heterojunctions composed of a tantalum nitride (Ta3N5) core and nitrogen-doped sodium tantalate (NaTaON) shell have been constructed via an in situ phase-induced etching chemical strategy. The photocatalytic water splitting performance of sub-20-nm Ta3N5@NaTaON junctions exhibits an extraordinarily high photocatalytic activity toward oxygen and hydrogen evolution. Most importantly, the combined experimental results and theoretical calculations reveal that the strong interfacial TaON bonding connection as a touchstone among Ta3N5@NaTaON junctions provides a continuous charge transport pathway rather than a random charge accumulation. The prolonged photoexcited charge carrier lifetime and suitable band matching between the Ta3N5 core and NaTaON shell facilitate the separation of photoinduced electron–hole pairs, accounting for the highly efficient photocatalytic performance. This work establishes the use of (oxy)nitride heterojunctions as viable photocatalysts for the conversion of solar energy into fuels. Multiband core–shell oxynitride nanocube heterojunctions owing to efficient spatial charge separation exhibit robust solar water splitting.

Publisher URL: http://onlinelibrary.wiley.com/resolve/doi

DOI: 10.1002/aenm.201700171