Study On Controlled Synthesis Of TiO₂ Nanosheets And Photocatalytic Mechanism For Composite System Based On TiO₂ Nanosheets

As we known,TiO₂ has been investigated extensively due to its high efficiency,high chemical stability,nontoxicity,low price and availability.However,because of its large band gap?3.2eV?,high recombination rate and low separation efficiency of photo-excited charge carriers,the light response range and the catalytic activity of TiO₂ are limited.In this work,AuPd alloy,NiS and Cu nanoparticles were selected to decorate the TiO₂ nanosheets to enhance the photocatalytic H2 evolution activity of TiO₂ nanosheets.And XRD,TEM,XPS,ESR,SPV and SPC were applied to investigate the Characterization of all samples.?1?A novel ultrathin 2D titanium dioxide?TiO₂?nanosheets decorated by AuPd bimetallic nanoalloys with highly active H2 evolution activity was prepared via a facile in situ synthesis method.The physical and photophysical properties of the as-prepared AuPd/TiO₂ nanosheets were characterized by XRD,TEM,DRS,XPS,ESR and SPC.The photocatalytic H2 evolution experiments indicate that the AuPd co-catalysts can efficiently promote the separation of photogenerated charge carriers in TiO₂,and consequently enhance the H2 evolution activity.A possible mechanism of the enhanced simulated sunlight catalytic performance of AuPd bimetallic nanoparticles?NPs?decorated TiO₂ nanosheets is proposed to guide further improvement of desirable functional materials.?2?Novel NiS cocatalyst decorating ultrathin 2D TiO₂ nanosheets photocatalysts were prepared via a simple in-situ synthesis approach.The properties of the as-prepared NiS/TiO₂ nanosheets were characterized by XRD,TEM,DRS,XPS.The photocatalytic hydrogen evolution and SPV experiments indicate that the NiS cocatalysts can significantly improve the separation of photogenerated electron-hole pairs in ultrathin 2D TiO₂ nanosheets and consequently enhance the hydrogen evolution performance.The photocatalytic mechanism of NiS cocatalysts on the enhancement of the photocatalytic activity of TiO₂ nanosheets is proposed and confirmed by SPV results.?3?The Cu/TiO₂ nanosheets composite was prepared in this work and the XRD,TEM,DRS,XPS was used to study the characteristic of samples.It is proved that the Cu cocatalysts can enhance the photocatalytic hydrogen activity of TiO₂ nanosheets,and the photocatalytic mechanism is proposed.In summary,suitable cocatalysts decorating photocatalyst is a promising way to enhance the separation rate of electon-holes and photocatalytic performance.