In-situ synthesis of novel ternary CdS/PdAg/g-C3N4 hybrid photocatalyst with significantly enhanced hydrogen production activity and catalytic mechanism exploration

Ternary CdS/PdAg/g-C3N4 hybrid photocatalyst was synthesized by a simple sonochemical method, and the sample exhibited excellent photocatalytic H-2 evolution performance up to 3098.3 mu mol g(-1) h(-1). This photo-catalytic hydrogen production activity is 968.2 times higher than that of g-C3N4. Meanwhile, the apparent quantum yield (AQY) of the ternary hybrid photocatalyst is 9.6% at 420 nm. The extension of optical response range is verified by ultraviolet-visible diffuse reflectance spectra (DRS). Enhancement of the charge separation efficiency is examined via photoluminescence (PL), surface photovoltage (SPV) and electron spin resonance (ESR). A reasonable catalytic mechanism of the ternary hybrid photocatalyst is proposed. As an electron-bridge, PdAg bimetallic alloy NPs can assist the photoelectrons to transfer from the CB of g-C3N4 to the CB of CdS, from where the photoelectrons react with hydrogen ion to release hydrogen. This work may pave a new way on designing high efficient ternary hybrid photocatalyst.

Automated summary

A ternary CdS/PdAg/g-C3N4 hybrid photocatalyst was synthesized using a simple sonochemical method, exhibiting excellent photocatalytic H-2 evolution performance up to 3098.3 mu mol g(-1) h(-1), which is 968.2 times higher than that of g-C3N4. The catalyst also showed an apparent quantum yield of 9.6% at 420 nm, and the enhancement of charge separation efficiency was confirmed through various tests including photoluminescence, surface photovoltage, and electron spin resonance. This work proposes a reasonable catalytic mechanism for the ternary hybrid photocatalyst, showing potential for designing high efficient ternary hybrid photocatalysts.