Plasmonic ternary hybrid photocatalyst based on polymeric g-C3N4 towards visible light hydrogen generation

Yuping Che,Bingxin Lu,Zhaoyue Liu,Jin Zhai,Kefeng Wang,Qingqing Liu

doi:10.1038/s41598-020-57493-x

Abstract

Surface plasmon resonance (SPR) effect of noble metal nanoparticles (NPs) for photocatalysis has a significant enhancement. In this system, a plasmonic ternary hybrid photocatalyst of Ag/AgBr/g-C3N4 was synthetized and used in water splitting to generation H2 under visible light irradiation. 18%Ag/AgBr/g-C3N4 showed the highest photoactivity, with the efficiency of hydrogen generation as high as 27-fold to that of pristine g-C3N4. Compared to simple mixture of Ag/AgBr and g-C3N4, hetero-composite Ag/AgBr/g-C3N4 showed a higher photoactivity, even though they contained same content of Ag/AgBr. We find that significant factors for enhancing properties were the synergistic effect between Ag/AgBr and g-C3N4, and the light absorption enhancing by SPR effect of Ag NPs. Ag/AgBr NPs firmly anchored on the surface of g-C3N4 and their high dispersion were also responsible for the improved activity and long-term recycling ability. The structure of Ag/AgBr/g-C3N4 hybrid materials and their enhancement to photocatalytic activity were discussed. Meanwhile, the possible reaction mechanism of this system was proposed.

Highlights

Surface plasmon resonance (SPR) effect of noble metal nanoparticles (NPs) for photocatalysis has a significant enhancement
Many studies have found that Ag as surface plasmon resonance (SPR) material which can be triggered by visible light is introduced into photocatalyst system
Photocatalysts decorated by Ag/AgCl exhibit excellent visible light absorption performance due to the synergistic effect of Ag/AgCl and SPR effect of Ag NPs32,35, Ag@AgCl36, Ag/AgCl/TiO2 nanotube arrays[37] and Ag/AgCl/Al2O338 showed high activity in degradation of organic pollutants (MO and MB) under visible light irradiation; Ag/AgBr hybrids display a synergistic effect between semiconductors and plasmonic metals and exhibit a considerably high photocatalytic performance for pentachlorophenol degradation[39]

Summary

Introduction

Surface plasmon resonance (SPR) effect of noble metal nanoparticles (NPs) for photocatalysis has a significant enhancement. We used this plasmonic ternary photocatalyst to generate H2 under visible light irradiation which demonstrated high efficiency for photocatalytic water splitting. We obtained that the enhancing absorption of composite photocatalysts in visible light region was mainly obtained from SPR effect of Ag. band gap (Eg) of g-C3N4 and AgBr could be calculated by Eq (1) and obtained from UV-vis spectra, as follows[49]: αhν = A(hν − Eg)n/2 (1)

Results

Conclusion