Metal/porphyrin Nanocomposites: Preparation And Photocatalysis

Pt nanoparticles stabilized by four different porphyrin molecules were prepared using alcohol reduction method. As-prepared Pt nanoparticles were characterized by UV-vis, TEM, FT-IR and XRD. Photocatalytic splitting of water using the nanocomposites as catalysts was performed to investigate the influences of the structures of porphyrin molecules to the photocatalytic activities.(1) Pt colloidal solution stabilized by 5,10,15,20-tetra-(4-hydroxyl benzene)-porphyrin (Pt@THBP) was prepared using glycol reduction method. The nanoparticles have mean particles size from 1 to 3 nm depending on the molar ratio of the metal and the stabilizer. Pt@THBP can split water to hydrogen irradiated under UV-Vis light. The rate of H2 formation is ca 2.23×10-4 mmol/min.(2) Pt nanoparticles stabilized by 5,10,15,20-tetra-(4-methyl benzene)-porphyrin (Pt@TMBP), which has four methyl groups on the porphyrin ring, were prepared. The photodecomposition of water showed that Pt@TMBP sol has higher catalytic activity than Pt@THBP. The rate of H2 formation is ca 3.35×10-4 mmol/min. The results demonstrate that the groups attached on the porphyrin ring influence photocatalytic activity. Methyl groups attached on the porphyrin ring increases the catalytic activity of Pt nanocomposite.(3) Pt colloidal solution stabilized by 5,10,15,20-tetra-(4-diphenyl amino-1- benzoyl)-porphyrin (Pt@TDABP) was prepared. The rate of H2 formation of Pt@ TDABP sol is 2.77×10-4 mmol/min. Pt nanoparticles stabilized by TDABP show higher stability. However, the photocatalytic activity of Pt@TDABP is weaker than that of Pt@TMBP.(4) Pt colloidal solution stabilized by 5,10,15,20-tetra-(4-diphenyl amino-1-styrene)- porphyrin (Pt@TDASP) was prepared. The rate of H2 formation of Pt@TDASP sol is 2.95×10-4 mmol/min. The result showed that photocatalytic activity is not influenced obviously by the bonding types between porphyrin and triphenylamine group.