A superlattice interface and S-scheme heterojunction for ultrafast charge separation and transfer in photocatalytic H<sub>2</sub> evolution.

Wan, Sijie; Wang, Wang; Cheng, Bei; Luo, Guoqiang; Shen, Qiang; Yu, Jiaguo; Zhang, Jianjun; Cao, Shaowen et al. · Nat Commun · 2024

basic_science · Level V

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Abstract

The rapid recombination of photoinduced charge carriers in semiconductors fundamentally limits their application in photocatalysis. Herein, we report that a superlattice interface and S-scheme heterojunction based on Mn<sub>0.5</sub>Cd<sub>0.5</sub>S nanorods can significantly promote ultrafast charge separation and transfer. Specifically, the axially distributed zinc blende/wurtzite superlattice interfaces in Mn<sub>0.5</sub>Cd<sub>0.5</sub>S nanorods can redistribute photoinduced charge carriers more effectively when boosted by homogeneous internal electric fields and promotes bulk separation. Accordingly, S-scheme heterojunctions between the Mn<sub>0.5</sub>Cd<sub>0.5</sub>S nanorods and MnWO<sub>4</sub> nanoparticles can further accelerate the surface separation of charge carriers via a heterogeneous internal electric field. Subsequent capture of the photoelectrons by adsorbed H<sub>2</sub>O is as fast as several picoseconds which results in a photocatalytic H<sub>2</sub> evolution rate of 54.4 mmol·g<sup>-1</sup>·h<sup>-1</sup> without any cocatalyst under simulated solar irradiation. The yields are increased by a factor of ~5 times relative to control samples and an apparent quantum efficiency of 63.1% at 420 nm is measured. This work provides a protocol for designing synergistic interface structure for efficient photocatalysis.