Jialin Fang

TiO2 nanotube array-graphene-CdS quantum dots composite film in Z-scheme with enhanced photoactivity and photostability.

The most efficient solar energy utilization is achieved in natural photosynthesis through elaborate cell membrane with many types of molecules ingeniously transferring photogenerated electrons to reactants in a manner similar to the so-called Z-scheme mechanism. However, artificial photosynthetic systems based on semiconductor nanoparticles are inevitably accompanied by undesired non-Z-scheme electron transfer and back reactions, which adversely affect the photoactivity and photostability of the systems. Herein, we report on a novel Z-scheme system with an electrochemically converted graphene (GR) film as the electron mediator interlayer contacted with both TiO2 nanotube (TNT) array and CdS quantum dots (CdS QDs) on two sides. The obtained TiO2 nanotube array-graphene-CdS quantum dots (TNT-GR-CdS) composite film shows higher photoelectric response and photocatalytic activities than other bare TNT, TNT-CdS, TNT-GR, and TNT-CdS-GR. Moreover, compared to TNT-CdS, the activity stability is significantly improved, and the residual amount of Cd element in reaction solution is reduced ∼8 times over TNT-GR-CdS. Various measurements of photoelectrochemistry and radicals reveal that the enhanced photoactivity and photostabilities of TNT-GR-CdS are due to the efficient spatial separation of the photogenerated electron-hole pairs and the restricted photocorrosion of CdS via an efficient Z-scheme mechanism under simulated sunlight.

ZnO photonic crystals with enhanced photocatalytic activity and photostability

ZnO photonic crystals (ZnO-PCs) with large area and high quality were prepared by a facile auto-forced impregnation method. The resulting ZnO-PCs exhibited remarkable photocatalytic performance and photocorrosion inhibition compared with porous and commercial nanoparticle ZnO.

Unusual photocatalytic materials with UV-VIS-NIR spectral response: deciphering the photothermocatalytic synergetic effect of Pt/LaVO4/TiO2

In the present paper, we propose a new type of catalyst, Pt/LaVO4/TiO2 (PLVT), which combines the use of UV and visible light for photocatalysis on LaVO4/TiO2 (LVT) and the heating effect of infrared light for low-temperature thermocatalysis on Pt. Under simulated solar light, benzene as an objective pollutant can be 100% eliminated and converted into CO2 and H2O on PLVT at 70 °C with an obvious synergetic effect of photocatalysis and thermocatalysis. The photothermocatalytic activity at 70 °C is about three times the sum of the photocatalytic activity and thermocatalytic activity. The stable performance of PLVT in a 60 hour durability test also indicates its applicable potential. The roles of Pt and LVT in the synergetic effect are discussed by comparing PLVT with control samples regarding the interaction between Pt and LVT under photothermocatalytic conditions. On the basis of the above experimental results, a possible mechanism of the synergetic effect is proposed.

Probing photonic effect on photocatalytic degradation of dyes based on 3D inverse opal ZnO photonic crystal

3D inverse opal ZnO photonic crystals (ZnO-PCs) with designed photonic bandgap (PBG) were prepared to study the pore size and slow photon effect on photocatalytic dye degradation. The PBGs of these ZnO-PC films were tuned experimentally by variation of the polystyrene sphere size of the opal templates. It was found that there is competition between the surface area and mass transport with increasing pore size during photocatalysis. ZnO-PCs exhibited higher photocatalytic activity under visible light irradiation, when the probe molecules were absorbed and well matched with the PBG. The enhancement could be attributed to intensified dye photosensitization as a result of the slow photon effect at the PBG edges, thus leading to a remarkable improvement in the light trapping. The present results provide useful information for developing high performance photocatalysts and photoanodes based on artificial photonic crystal design.

A large-area smooth graphene film on a TiO2 nanotube array via a one-step electrochemical process

A large-area smooth graphene film on a TiO2 nanotube array was directly fabricated using a simple, green and low-cost electrochemical process. The controllable formation mechanism of the graphene film is demonstrated in detail. The enhanced photoelectric and photocatalytic properties of the composite film imply great potential applications in various fields.