Gold/monolayer graphitic carbon nitride plasmonic photocatalyst for ultrafast electron transfer in solar-to-hydrogen energy conversion

Abstract

Gold (Au) plasmonic nanoparticles were grown evenly on monolayer graphitic carbon nitride (g-C3N4) nanosheets via a facile oil-bath method. The photocatalytic activity of the Au/monolayer g-C3N4 composites under visible light was evaluated by photocatalytic hydrogen evolution and environmental treatment. All of the Au/monolayer g-C3N4 composites showed better photocatalytic performance than that of monolayer g-C3N4 and the 1% Au/monolayer g-C3N4 composite displayed the highest photocatalytic hydrogen evolution rate of the samples. The remarkable photocatalytic activity was attributed largely to the successful introduction of Au plasmonic nanoparticles, which led to the surface plasmon resonance (SPR) effect. The SPR effect enhanced the efficiency of light harvesting and induced an efficient hot electron transfer process. The hot electrons were injected from the Au plasmonic nanoparticles into the conduction band of monolayer g-C3N4. Thus, the Au/monolayer g-C3N4 composites possessed higher migration and separation efficiencies and lower recombination probability of photogenerated electron-hole pairs than those of monolayer g-C3N4. A photocatalytic mechanism for the composites was also proposed.