Nanosilver supported on inert nano-diamond as a direct plasmonic photocatalyst for degradation of methyl blue

Abstract

Direct photocatalysis with plasmonic nanostructures represents a new and promising direction in pollutant disposal. In current practice, inert metal oxides are usually used as supports to load plasmonic nanoparticles. However, due to the lack of stabilizing functional groups on the surface of these metal oxides, the stability and dispersibility of the obtained nanostructures are poor. Herein, a nano-diamond (ND) material with easily functionalized surface was used as an inert support to load silver nanoparticles to prepare plasmonic nanostructures with direct photocatalytic ability. The plasmonic nanostructure can be easily prepared by modifying the surface of ND with pyridine groups and then reducing the silver precursor in-situ. Thanks to pyridine group's dual functions of complexing Ag nanocrystals and dispersing ND, the obtained plasmonic nanostructure not only has uniformly distributed Ag nanocrystals on ND surface, but also shows excellent multi-solvent dispersibility. we demonstrate that this novel plasmonic nanostructure can directly decolorization of methyl blue (MB) under visible light irradiation with a standard rate constant as high as 28.4 s−1 g−1. In addition, the catalyst can be easily recovered and recycled for at least five times while maintaining high catalytic activity. The mechanism study shows that the localized surface plasmon resonance energy transfer of Ag nanoparticles is the direct driving force of MB degradation. The inert ND support can not only ensure the physical stability of Ag nanoparticles, but also avoid the attenuation of plasmonic resonance energy to matrix, which plays an indispensable synergistic role in promoting the rapid degradation of MB.