Zhuoyin Peng

Self-assembly of Pt nanocrystals/one-dimensional titanate nanobelts heterojunctions and their great enhancement of photocatalytic activities

In the present work, novel layered-structure titanate (H2Ti5O11·3H2O) nanobelts are synthesized by a hydrothermal method and then Pt nanocrystals/titanate nanobelts heterojunctions with high yield, well dispersion and tight interaction are self-assembled via the linker molecule of thioglycolic acid. Their photocatalytic activity for the degradation of methyl orange solution is enhanced by increasing the Pt precursors content ratio. The degradation ratio of the heterojunctions with 11.0 wt% Pt nanocrystals will increase to 100% and 68.2% from 62% and 5% for pure titanate nanobelts after 300 min irradiation under UV and visible light irradiation, respectively. These are better when compared with similar reports, as the heterojunctions will suppress the recombination of electron-hole pairs in titanate nanobelts, where the Pt particles act as electron traps aiding electron-hole separation.

Enhanced visible photocatalytic activity of Cu2O nanocrystal/titanate nanobelt heterojunctions by a self-assembly process

In the present work, we introduce a facile and widely used route to fabricate Cu2O nanocrystal/titanate nanobelt heterojunctions with high yield, good dispersion and tight interaction, and which are self-assembled via the linker molecule 3-mercaptopropionic acid. Their photocatalytic activity for the degradation of methyl orange solution is enhanced by decorating with Cu2O nanocrystals, especially in the visible light region. The degradation rates of 6 wt% Cu2O/titanate heterojunctions are both the highest at 100% after 80 and 180 minutes irradiation under UV and visible light irradiation, while those of the pure titanate nanobelts are only 20% and 3%, respectively. These lower values for the pure titanate nanobelts are due to the p–n heterojunctions suppressing the recombination of electron–hole pairs in the titanate nanobelts, where the Cu2O nanocrystals act as electron traps aiding electron–hole separation. Additionally, a synergistic effect from the tight contact between Cu2O nanocrystals and titanate nanobelts also efficiently enhances the photodegradation of the Cu2O/titanate heterojunctions.

Fabrication of TiO2 nanotube arrays and their application in flexible dye-sensitized solar cells

TiO2 nanotube arrays have been widely used as the photoelectrode in dye-sensitized solar cells (DSSCs). In this work, free-standing TiO2 nanotube arrays were prepared by two-step electrochemical anodization of titanium foils, then the TiO2 nanotube arrays were transferred to a flexible ITO/PEN substrate using titania slurries. SEM images showed that the TiO2 nanotube arrays with different lengths (10, 14, 20 and 30 μm) were successfully obtained. The photovoltaic properties for incident photon to current efficiency (IPCE) and photovoltaic conversion efficiency were also studied, showing that the best photovoltaic conversion efficiency of DSSCs based on 20 μm length TiO2 nanotube arrays was 3.44%.

Influence of interface combination of reduced graphene oxide/P25 composites on their visible photocatalytic performance

Reduced graphene oxide (RGO)/P25 composites are successfully synthesized by using a facile hydrothermal method, and Raman mapping images show that the P25 are very uniformly dispersed in the composite. The RGO/P25 composites are used in the photocatalysis of methyl orange under UV and visible light illumination. The degradation ratio for the 0.75 wt% RGO/P25 composite is the best with 100% degradation after 120 and 150 minutes of irradiation under UV and visible light, respectively, which is greatly enhanced compared with that of P25, especially in the visible light region. It is found that a good interface combination between RGO and P25 may improve the electric conductivity and lifetime of photo-induced electrons in the photodegradation process as well as enhance the light absorption, which may favor the efficient enhancement of the photodegradation rate of the RGO/P25 composite.