Ta_3N_5@Ta_2O_5的可控制备及可见光催化分解水析氢性能  

Controllable Synthesis of Ta_3N_5@Ta_2O_5 and Properties of Splitting Water into Hydrogen under Visible Light Irradiation

作　　者：张微[1,2] 姜洪泉[1,2] ZHANG Wei;JIANG Hong-Quan(Key Laboratory for Photonic and Electric Bandgap Materials,Ministry of Education,Harbin Normal University,Harbin 150025,China;Key Laboratory of Functional Materials and Green Catalysis,Colleges of Heilongjiang Province,Harbin Normal University,Harbin 150025,China)

机构地区：[1]哈尔滨师范大学光电带隙材料省部共建教育部重点实验室,哈尔滨150025 [2]哈尔滨师范大学功能材料设计合成与绿色催化黑龙江省高校重点实验室,哈尔滨150025

出　　处：《无机化学学报》2018年第9期1591-1599,共9页Chinese Journal of Inorganic Chemistry

基　　金：黑龙江省教育厅科学技术研究项目(No.12531213);光电带隙材料省部共建教育部重点实验室开放课题(No.PEBM201708)资助

摘　　要：以水热法制备的Ta_2O_5纳米粒子为前驱体,利用高温氮化技术成功制备了核壳异质结构的Ta_3N_5@Ta_2O_5纳米光催化剂。采用XRD、XPS、TEM、N_2吸附-脱附测试、DRS及电化学测试等分析手段,考察了氮化温度和氮化时间对样品的表面组成、晶粒尺寸、晶面结构、能带结构及载流子分离效率的影响规律。在NH_3气流量50 mL·min^(-1)的条件下,当氮化温度为750℃,控制氮化时间能够对纳米Ta_2O_5样品的带隙结构在3.86~2.08 eV间有效调控,相应地样品逐渐从Ta_2O_5经TaON@Ta_2O_5转化为Ta_3N_5@Ta_2O_5;当氮化时间为3 h,氮化温度由750℃升高到900℃,Ta_3N_5@Ta_2O_5样品的带隙窄化至2.04 eV;当氮化温度为850℃,氮化时间延长至12 h,Ta_2O_5完全氮化为Ta_3N_5,带隙进一步窄化至2.02 eV。经850℃氮化3 h样品,壳层Ta_3N_5界面转化为高活性(110)晶面,光生载流子分离效率最大,在可见光(λ>420 nm)照射下光解水析氢活性最高,达21.75μmol·g^(-1)·h^(-1)。Ta3N5@Ta2O5 nano-photocatalysts with shell-core heterojunction structure were successfully synthesized by a high-temperature ammonolysis of Ta2O5 nano-powders prepared by a hydrothermal method.Effects of nitridation temperature and nitridation time on surface composition,crystal plane structure,energy band structure,and carrier separation efficiency of the samples were investigated by X-ray diffraction(XRD),X-ray photoelectron spectroscopy(XPS),transmission electron microscopy(TEM),N2 adsorption-desorption test,UV-Vis diffused reflectance spectroscopy(DRS),and electrochemical measurements.Under the condition of ammonia flowing rate of 50 mL·min-1 and nitriding temperature of 750℃,the bandgap structure of Ta2O5 samples could be controlled effectively between 3.86~2.08 eV,through transforming the phases from Ta2O5 to TaON@Ta2O5,and to [e-mail] the nitriding temperature was elevated from 750 to 900℃,the bandgap energy of Ta3N5@Ta2O5 was further narrowed to be about 2.04 eV by 3 h nitridation.When the nitridation time was prolonged to 12 h,Ta2O5 was completely transformed into Ta3N5,of which the bandgap energy was further narrowed to 2.02 eV,by nitriding at 850℃.After nitriding at 850℃for 3 h,the crystal plane of Ta3N5 shell gradually changed to the(110),and the sample possessed the highest carrier separation efficiency,on which optical H2 evolution rate reaches 21.75μmol·g^-1·h^-1 under visible light(λ>420 nm)irradiation.

关 键 词：TA2O5 Ta3N5 异质结 光催化 分解水 半导体 非均相催化 电荷转移 

分 类 号：O614.513[理学—无机化学]