Research On The Photoresponse And Photocatalysis Of TiO₂/SiC Composite

The environment pollution issue has drawn more and more attention of the public alongwith the development of the industry. Photocatalysis, which is based on the photoelectriceffect of semiconductors, can transfer optical energy into chemical energy and hence breakdown the pollution. Among all the photocatalyst, TiO₂is undoubtedly the most shiningone, for its non-toxic and harmlessness, stableness, no secondary pollution, as well as longtime effect. But owing to its wide band gap and quick recombination ratio of photoinducedelectron-hole pairs, its utilization of the sunlight and conversion rate of photon is so lowthat the application is strongly limited. It is found that those two short comings can beovercome by the herterojunction, hence the photocatalyst property is increased.Volatile organic compounds （VOCs）, as a kind of gas, which is commonly released bythe decorative materials, and owing to the neatly contaction with people but poisonous tohuman beings, has drawn the attention of the public. On the issue of how to select thesuitable photocatalyst quickly, our group has worked day by day and finally a highthroughput selection platform was successfully created. Due to the neatly connection ofphotocatalysis and photocurrent, it is hoped that the suitable material for the degradationof different VOCs is quickly found.In this work, the interaction between catalyst and water is taken into consideration and ahydrophobic SiC was chosen to combine with hydrophilic TiO₂. Based on the screenprinting technique, a chip, on which different TiO₂/SiC compositions were printed, andtheir photocurrent in different humid conditions were tested. It is found that thephotocurrent is increased when the percentage of SiC is about1%²%, and theenhancement is even stronger in humid condition, as well as the durability. Theirphotocatalyst degradation of toluene in different humid conditions is also carried out, andgood correspondence with photocurrent is finally found. Furthermore, to enhance theseparation of photoinduced carrier, sine wave alternating current （AC） and direct current（DC） bias were applied in the photocatalyst degradation of toluene by TiO₂. It is foundthat the enhancement is limited but under half-sine-waved direct bias, TiO₂gained an excellent photocatalyst property in humid condition.This work is helpful for the understanding of the relationship between photocurrent,photocatalysis and electric aided photocatalysis. The results express a new way in dealingwith environment pollution.