Semiconductor oxides are widely used to achieve photocatalytic removal of NOx(NO and NO2) species. These materials also exhibit enhanced oxidation ability in thermally assisted photocatalysis;however, many of them tend to be deactivated at high relative humidity(RH) levels. In the case of the benchmark P25 TiO2 photocatalyst, we observe a significant decrease in non-NO2 selectivity from 95.02% to 58.33% when RH increases from 20% to 80%. Interestingly, the porous TiO2(B) microspheres synthesized in this work exhibit 99% selectivity at 20% RH;the selectivity remains as high as 96.18% at 80% RH. The high humidity tolerance of the TiO2(B) sample can be ascribed to its strong water desorption capacity and easy O2 adsorption at elevated temperatures, which reflects the fact that the superoxide radical is the main active species for the deep oxidation of NOx. This work may inspire the design of efficient photothermal catalysts with application in NOx removal in hot and humid environments.
He MaChanghua WangSongmei LiXintong ZhangYichun Liu
The electron transport layer （ETL） plays an important role in planar heterojunction perovskite solar cell （PSCs）, by affecting the light-harvesting, electron injection and transportation processes, and especially the crystal- lization of perovskite absorber. In this work, we utilized a commercial TKD-TiO2 nanoparticle with a small diameter of 6 nm for the first time to prepare a compact ETL by spin coating. The packing of small-size particles endowed TKD-TiO2 ETL an appropriate surface-wettability, which is beneficial to the crystallization of perovskite deposited via solution-processed method. The uniform and high-transmittance TKD-TiO2 films were successfully incorporated into PSCs as ETLs. Further careful optimization of ETL thickness gave birth to a highest power conversion efficiency of 11.0%, which was much higher than that of PSC using an ETL with the same thickness made by spray pyrolysis. This TKD-TiO2 provided a universal solar material suitable for the further large-scale production of PSCs. The excellent morphology and the convenient preparation method of TKD-TiO2 film gave it an extensive application in photovoltaic devices.
Peng ChenYinglin WangMeiqi WangXintong ZhangLingling WangYichun Liu
TiO2 heterojunction with different TiO2 phases has been widely adopted for enhanced photocatalysis.Therein,a less common anatase/bronze TiOz heterojunction,also named as anatase/TiO2(B)heterojunction,has recently drawn increasing interest.In this review,the structural advantages of anatase/bronze TiO2 heterojunction for enhanced photocatalysis is highlighted in terms of less lattice mismatch and better charge separation at the interface.Besides photocatalysis,the anatase/bronze TiO2 heterojunction is proven a promising candidate for heat-assisted photocatalysis,named as photothermal catalysis.Further,the anatase/bronze TiO2 heterojunction can serve as a good model to evaluate the strategy for improved photocatalysis and even photothermal catalysis.Herein,the recent attempts on boosting the photocatalytic and photothermal catalytic performance of anatase/bronze TiO2 heterojunction are summarized.It is expected that this review would arouse renewed interest for revisiting TiO2 heterojunction in photocatalysis,photothermal catalysis and other advanced photocatalysis.
Photocatalysis shows great promise in the field of solar energy conversion.One of the reasons for this is because it promotes the development of multi-field-coupled catalysis.In order to explore the principles of multi-field-coupled catalytic reactions,an in situ multi-field-coupled characterization technique is required.In this study,we obtained hydrogenated ST-01 TiO2 and observed enhanced catalytic activity by thermal coupled photocatalysis.In situ photoconductivity was employed to understand the activity enhancement.The effects of the reaction temperature,reaction atmosphere,and oxygen vacancy(Ov)on the photoconductivity of TiO2 were studied.After coupling thermal into photoconductivity measurement,highly active Ov-TiO2 displayed rapid decay of photoconductivity in a CO2 atmosphere and slow decay of photoconductivity in a N2 atmosphere.These phenomena revealed that photothermal coupling assisted the detrapping of electrons at the Ov surface and promoted electron transfer to CO2,which clearly explained the high photothermal catalytic activity of Ov-TiO2.This study demonstrated that photoconductivity is a useful tool to help understand photothermal catalytic phenomena.
Dashuai LiYu HuangSongmei LiChanghua WangYingying LiXintong ZhangYichun Liu
