Pt Nanoparticle Assisted Homogeneous Surface Engineering of Polymer-Based Bulk-Heterojunction Photocathodes for Efficient Charge Extraction and Catalytic Hydrogen Evolution

To fabricate a high-efficiency bulk-heterojunction (BHJ)-based photocathode, introducing suitable interfacial modification layer(s) is a crucial strategy. Surface engineering is especially important for achieving high-performance photocathodes because the photoelectrochemical (PEC) reactions at the photocathode/electrolyte interface are the rate-limiting process. Despite its importance, the influence of interfacial layer morphology regulation on PEC activity has attracted insufficient attention. In this work, RuO2, with excellent conductivity, capacity and catalytic properties, is utilized as an interfacial layer to modify the BHJ layer. However, the homogeneous coverage of hydrophilic RuO2 on the hydrophobic BHJ surface is challenging. To address this issue, a Pt nanoparticle-assisted homogeneous RuO2 layer deposition method is developed and successfully applied to several BHJ-based photocathodes, achieving superior PEC performance compared to those prepared by conventional interface engineering strategies. Among them, the fluorine-doped tin oxide (FTO)/J71:N2200(Pt)/RuO2 photocathode generates the best photocurrent density of -9.0 mA cm(-2) at 0 V with an onset potential of up to 1.0 V under AM1.5 irradiation.

Automated summary

In order to create a high-efficiency bulk-heterojunction (BHJ)-based photocathode, it is crucial to introduce suitable interfacial modification layer(s). Surface engineering plays a significant role in achieving high-performance photocathodes as the photoelectrochemical reactions at the photocathode/electrolyte interface are the limiting process. However, the impact of interfacial layer morphology regulation on PEC activity has not received enough attention. In this study, a Pt nanoparticle-assisted homogeneous RuO2 layer deposition method was developed to overcome the challenge of uniform coverage of hydrophilic RuO2 on the hydrophobic BHJ surface, leading to improved PEC performance compared to conventional interface engineering strategies. The FTO/J71:N2200(Pt)/RuO2 photocathode exhibited the best photocurrent density of -9.0 mA cm(-2) at 0 V with an onset potential of up to 1.0 V under AM1.5 irradiation.