Establishing dual hole transfer channels to achieve long-lived trapped holes for significantly enhancing the photocatalytic pure water splitting performance of ZnIn2S4

Photocatalytic pure water splitting provides a promising strategy to produce green hydrogen. ZnIn 2 S 4 , as a visible light responsive photocatalytst, has been proven to be the capable of direct pure water splitting into H 2 and H 2 O 2 . Currently, the efficiency of ZnIn 2 S 4 is severely restricted by the slow hole transport dynamics and low utilization of holes. Herein, a ternary Ni 2 CoPO x @ZnIn 2 S 4 @CoO x (NCP@ZIS@Co) photocatalyst was constructed by directly growing ZnIn 2 S 4 on the Ni 2 CoPO x nanosheet and subsequently decorating ultra-small CoO x cluster on the surface of ZnIn 2 S 4 . Experimental characterizations reveal that dual hole transfer channels are established by designing the spatial separation of Ni 2 CoPO x and CoO x , which can efficiently extract holes from ZnIn 2 S 4 , thus improving the charge separation. Moreover, the lifetime of trapped holes is significantly prolonged from 804.1 ps to 2146.2 ps, which enable more photogenerated holes to participate in the photocatalytic reactions. As a result, the optimal NCP@ZIS@Co shows an excellent H 2 and H 2 O 2 evolution rates of 1541.2 μmol g −1  h −1 and 1381.1 μmol g −1  h −1 under visible light irradiation, respectively, with an apparent quantum efficiency (AQE) of 7.62 % at 400 nm. This work provides a useful way to manipulate the photogenerated holes dynamic for improving photocatalytic performance.