Nano-Au-modified TiO 2 grown on dendritic porous silica particles for enhanced CO 2 photoreduction

Titania dioxide (TiO2) is widely studied for photocatalytic CO2 reduction among various semiconductor pho-tocatalysts due to simple preparation, low cost, high stability and suitable band gap. However, the CO2 conversion efficiency of most TiO2-based photocatalysts is still relatively low, especially in the visible light region owing to their weak light absorption capacity. In this work, we employed dendritic porous silica nanospheres (DPSNs) with center-radial large pores as a carrier to grow TiO2 nanoparticles (NPs) on the surface of center radial pores and then load small Au NPs on the well-dispersed TiO2 NPs. Eventually, a series of DPSNs@TiO2@Au nanocomposites with different sizes of Au NPs were successfully constructed by controlling the calcination time. Due to the introduction of Au with the Local Surface Plasmaon Resonance (LSPR) effect, DPSNs@TiO2@Au with appropriate size (3-5 nm) of Au NPs exhibited superior CH4 production rate of 34.25 mu molg-TiO2@Au1h-1, medium CO production rate of 15.27 mu molg-TiO2@Au-1h-1 and high cycle stability under simulated sunlight irradiation with 300 W Xe lamp. This work may provide some inspiration for the design of the supported photocatalysts.

Automated summary

In this study, dendritic porous silica nanospheres were used as a carrier to grow TiO2 nanoparticles and load gold nanoparticles, leading to the successful construction of a series of DPSNs@TiO2@Au nanocomposites. Under simulated sunlight irradiation, DPSNs@TiO2@Au with appropriate size of Au NPs (3-5 nm) exhibited superior CH4 and CO production rates as well as high cycle stability.