Large enhanced photocatalytic activity of g-C 3 N 4 by fabrication of a nanocomposite with introducing upconversion nanocrystal and Ag nanoparticles.

A novel heterostructured nanocomposite UCNPs@SiO 2 @Ag/g-C 3 N 4 was developed for the first time to substantially boost the solar-light driven photocatalytic activity of g-C 3 N 4 . Its photocatalytic properties and photocatalytic mechanism were investigated. The as-synthesized photocatalyst with excellent improvement in the solar absorption and separation efficiency of photoinduced electron-hole pairs exhibited optimum solar-induced photocatalytic activity in dye degradation and hydrogen production. The experimental results showed that the rates of degradation of Rhodamine B (RhB) and hydrogen evolution were about 10 and 12 times higher than that of pristine g-C 3 N 4 , respectively. The excellent photocatalytic activity was attributed to the synergetic effect of upconversion nanoparticles (UCNPs) and Ag nanoparticles (NPs) on the modification of the photocatalytic properties of g-C 3 N 4 , resulting in a broad light response range for g-C 3 N 4 as well as the fast separation and slow recombination of photoinduced electron-hole pairs. This study provides new insight into the fabrication of g-C 3 N 4 -based nanocomposite photocatalysts with high catalytic efficiency through the artful assembly of UCNPs, Ag NPs and g-C 3 N 4 into a hetero-composite nanostructure. The prominent improvement in photocatalytic activity enables the potential application of g-C 3 N 4 in the photocatalytic degradation of organic pollutants and hydrogen production utilizing solar energy.