Preparation Of Visible Light Photocatalytic Nanometer Tantalum Oxynitride And Properties Of Splitting Water Into Hydrogen

Photocatalytic water splitting using solar energy has received a greatdeal of attention since it has been considered as one of the potential waysto provide clean and renewable energy of H2. However, most ofphotocatalysts as found are only responsive under ultraviolet(UV) light,which accounts for only a small fraction (4%) of the solar spectmm onthe earth surface. When N element is introduced into a transition metaloxide, the transition metal oxynitrides exhibit strong absorption in thevisible region due to the higher valence band which consisted ofhybridized N2p and O2p orbital. That can lead to potential photoeatalyticapplications under visible-light excitation. In the past several years, therehas been a growing concern about the synthesize of new types of highactive visible-light-driven oxynitride photoeatalyst. In this paper, theTaON prepared by nitriding reaction and a transition metal oxide as amaterial for the nitridation reaction, TaON with a narrow energy gap andvisible light responsive photocatalysts.The Ta2O5prepared by rapid hydrolysis reaction, the optimumreaction conditions: the temperature is850℃, ammonia flowing rate of90ml/min, nitriding time is10h. And the samples characterized by X-ray diffraction, UV-VIS, and field emission scanning electron microscopy. Bychanging the morphology of the catalyst, we obtained TaON fibers,porous TaON, fine particles of TaON, the small particles TaON havingthe largest surface area, reaches109.2m2/g, as this,under visible lightirradiation the methylene blue50PPm solution for120min, itsconcentration decreased by96%. so the small particles of TaON has thebest photocatalytic activity.The amorphous Ta2O5immersed in zirconyl chloride solution, driedand calcined, nitrogen in ammonia at850℃, the ZrO2/TaON visiblecomposite catalyst is prepared. The prepared samples were characterizedby XRD, TEM, SEM and UV-VIS. After loading the promoter RuO2,photocatalytic properties of the ZrO2/TaON has been significantlyimproved. Since highly dispersed cocatalyst is conducive to rapidprogress of the reaction, The rate of hydrogen production reaches5umol/h when the content of RuO2with2wt%and showes the highestactivity,But when loading exceeds3wt%about RuO2, the photocatalyticactivity decreased significantly.The tantalum powder as raw material is used to a hydrothermaltreatment in a fluorine-containing ionic solution, and then nitrided,calcined in air, thus a high activity γ-TaON powder obtained, And theγ-TaON composite with CdS forming a heterojunction structure, Tosuppress the light etching of CdS in an aqueous solution, a layer of ZnS is coated in the surface of CdS. Finally ZnS/CdS/γ-TaON photocatalyst isobtained,and in the results of photocurrent show a substantial increase inits activity. Under visible light irradiation, the ZnS/CdS/γ-TaONcomposite photocatalyst showes the highest activity When the content ofZnS/CdS is20wt%, and the hydrogen production rate reaches20umol/h.