摘要
Hydrogen evolution is accelerated via molecular surface assembly that regulates electronic structure and microenvironment • Anchoring amine-rich polyethyleneimine (PEI) onto Pt/g-C 3 N 4 composite realizes a HER rate of 28.34 mmol g −1 h −1 • The HER rate of Pt/g-C 3 N 4 /PEI improves to 40.40 mmol g −1 h −1 in simulated seawater • The incorporated PEI enhances the built-in electric field at interface, facilitating charge separation and transfer • The proton-buffering capability of PEI creates a alkaline microenvironment that accelerates water activation kinetics Photocatalytic hydrogen evolution in neutral or alkaline media is severely hampered by the sluggish kinetics of water activation/dissociation, which acts as the rate-limiting step. Guided by density functional theory (DFT) calculations, we report a simple yet effective surface assembly strategy to realize a significant enhancement in photocatalytic hydrogen evolution reaction (HER). The amine-rich polymer of polyethyleneimine (PEI) was strongly adsorbed on the surface of composite photocatalyst of Pt and graphitic carbon nitride (g-C 3 N 4 ). The PEI incorporation could not only strengthen the built-in electric field at the interface of Pt and g-C 3 N 4 , but also create a local alkaline environment due to the protonation of the amine groups. As a result, we achieved a remarkable HER rate of 28.34 mmol g −1 h −1 , more than double of the photocatalyst without PEI incorporation. The apparent quantum yield at 420 nm also dramatically increased from 3.1% to 9.5%. This PEI-induced HER enhancement reached its maximum in a neutral medium, helping to realize a high HER rate of 40.40 mmol g −1 h −1 in simulated seawater, which is neutral. This work opens up a feasible avenue for developing high-performance photocatalysts tailored for HER in neutral and weakly alkaline media. Download: Download high-res image (195KB) Download: Download full-size image
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