Leilei Luo

Facile green synthesis of crystalline polyimide photocatalyst for hydrogen generation from water

A simple green process based on thermal condensation is developed to synthesize polyimide. The obtained product possesses a high degree of crystallinity and exhibits efficient photocatalytic activity for hydrogen production from water under visible light.

Simultaneous sensitization and hole activation in carbon nitride polymer sensitized TiO2

Experimental and theoretical methods have combined to explore the role of carbon nitride polymer (CNP) in the photocatalytic performance of CNP-sensitized TiO2 (P25). In this work, CNP rather than its precursors has been used to directly sensitize TiO2 at 170 °C based on acid–base interaction and the photocatalytic performance of CNP-sensitized TiO2 is evaluated by degradation of methyl orange under visible light irradiation. The obtained results show the photocatalytic performance of CNP-sensitized TiO2 is obviously stronger than TiO2 and CNP. The high performance results not only from transferring the photoinduced electrons from CNP to the conductivity band (CB) of TiO2 and the increased separation efficiency of photoinduced electrons and holes, but also possibly from hole activation. Hole activation may result from the interaction between TiO2 and CNP, which increases the oxidation ability of the photoinduced hole that leaves the CNP skeleton after light irradiation.

Hemoglobin immobilized within mesoporous TiO2–SiO2 material with high loading and enhanced catalytic activity

Hemoglobin (Hb) is immobilized within the channels of mesoporous TiO2–SiO2 materials. It was found that mesoporous TiO2–SiO2 material can immobilize more Hb than mesoporous SiO2 and the greatest loading is achieved on the sample with an optimized Ti/Si molar ratio of 4 : 6. The high loading of Hb in mesoporous TiO2–SiO2 material is attributed to the increased electrostatic interaction between Hb and the pore wall which possesses enhanced electron donating capacity after the lower electronegative Ti substitutes Si in the framework of mesoporous SiO2. Unlike its easy leaching from the pore of mesoporous SiO2, Hb can hardly be released once immobilized within mesoporous TiO2–SiO2 material. The immobilized Hb retains not only its structure like that of the native one in the aqueous solution, but also the catalytic activity. Specifically, Hb has a higher catalytic activity when immobilized within mesoporous TiO2–SiO2 material than that when immobilized within mesoporous SiO2. Furthermore, the catalytic activity of Hb increases when the Ti/Si molar ratio of mesoporous TiO2–SiO2 material changes from 2 : 4 to 4 : 6, which stems from the increasing Hb density in the pore of mesoporous TiO2–SiO2 material. However, the catalytic activity decreased when the Ti/Si molar ratio became 6 : 4 due to the low occupational volume of Hb.