Interface Band Engineering Charge Transfer for 3D MoS2 Photoanode to Boost Photoelectrochemical Water Splitting

In photoelectrochemical (PEC) cells, it is a crucial issue to steer the charge flow in the electrode, including the internal movement of charge in the catalyst and the charge transfer across the catalyst substrate interface toward the external circuit. Here, we fabricated vertically aligned MoS2 nanosheets (NSs) on carbon fiber cloth (CFC) substrates decorated without and with a Au layer as two photoanodes for PEC water splitting, whereby the interface electron transfer mediated by the embedded Au was demonstrated to contribute to photoelectrode performance. The photoexcited Au plasmon switches the interface barrier from n-type Schottky to a p-type one, making the built-in potential act in accordance with external positive potential to together drive electron transfer and charge separation at the interface. The enhanced electron-transfer dynamic at the Au-embedded interface is determined in terms of the output current, impedance, and incident photon-to-current conversion measurements, being responsible for the significantly increased PEC activity in the MoS2/Au@CFC photoelectrode. This work gains insight into the importance of engineering charge transfer across the catalyst-substrate interface in PEC electrodes.