CAJ | 학술논문

采用模板法制备了CuO-CeO2-SiO2和稀土掺杂的CuO-Ce0.9M0.1O2-SiO2(M=La, Pr, Nd)催化剂.运用X射线衍射(XRD), N2吸附-脱附,透射电镜(TEM),拉曼(Raman)光谱, X射线光电子能谱(XPS)和氢气-程序升温还原(H2-TPR)等手段对催化剂的结构进行表征,并考察稀土掺杂对氯化氢催化氧化制氯气性能的影响.结果表明,稀土掺杂进入CeO2晶格中形成良好的固溶体结构,获得更小的晶粒尺寸和更高的比表面积,并且显著提高了固溶体的表面氧空位浓度.稀土掺杂显著影响了催化剂的氯化氢催化氧化活性,活性顺序为： CuO-Ce0.9La0.1O2-SiO2>CuO-Ce0.9Nd0.1O2-SiO2>CuO-Ce0.9Pr0.1O2-SiO2>CuO-CeO2-SiO2,固溶体氧空位浓度的高低与氯化氢氧化活性直接相关.通过与Ce0.9M0.1O2-SiO2催化剂的结构和性能的对比,发现氧空位浓度的提高并不能增强在固溶体表面发生的氯化氢氧化反应.动力学测试显示,稀土掺杂后,氧分子的吸附成为反应过程的决速步骤.但在V(O2)：V(HCl)=1条件下,更高的氧空位浓度导致了固溶体更低的氯化氢氧化反应速率.结合机理分析认为, CuO-Ce0.9M0.1O2-SiO2催化剂更高的氧空位浓度增强了固溶体表面的“氧溢流”,加快了氯化氢氧化的整体反应速率,这是CuO-Ce0.9M0.1O2-SiO2具备高活性的关键.
채용모판법제비료CuO-CeO2-SiO2화희토참잡적CuO-Ce0.9M0.1O2-SiO2(M=La, Pr, Nd)최화제.운용X사선연사(XRD), N2흡부-탈부,투사전경(TEM),랍만(Raman)광보, X사선광전자능보(XPS)화경기-정서승온환원(H2-TPR)등수단대최화제적결구진행표정,병고찰희토참잡대록화경최화양화제록기성능적영향.결과표명,희토참잡진입CeO2정격중형성량호적고용체결구,획득경소적정립척촌화경고적비표면적,병차현저제고료고용체적표면양공위농도.희토참잡현저영향료최화제적록화경최화양화활성,활성순서위： CuO-Ce0.9La0.1O2-SiO2>CuO-Ce0.9Nd0.1O2-SiO2>CuO-Ce0.9Pr0.1O2-SiO2>CuO-CeO2-SiO2,고용체양공위농도적고저여록화경양화활성직접상관.통과여Ce0.9M0.1O2-SiO2최화제적결구화성능적대비,발현양공위농도적제고병불능증강재고용체표면발생적록화경양화반응.동역학측시현시,희토참잡후,양분자적흡부성위반응과정적결속보취.단재V(O2)：V(HCl)=1조건하,경고적양공위농도도치료고용체경저적록화경양화반응속솔.결합궤리분석인위, CuO-Ce0.9M0.1O2-SiO2최화제경고적양공위농도증강료고용체표면적“양일류”,가쾌료록화경양화적정체반응속솔,저시CuO-Ce0.9M0.1O2-SiO2구비고활성적관건.
CuO-CeO2-SiO2 and rare-earth-doped CuO-Ce0.9M0.1O2-SiO2 (M=La, Pr, Nd) catalysts for recycling Cl2 from HCl oxidation were prepared by a template method, using activated carbon as a hard template. The catalyst structures were determined using X-ray diffraction (XRD), N2 adsorption-desorption, transmission electron microscopy (TEM), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and H2 temperature-programmed reduction (H2-TPR). The catalytic performances were also investigated. The results showed that La, Pr, and Nd cations were incorporated into the CeO2 lattice and formed nanosized solid solutions;this greatly reduced the catalyst grain sizes, leading to higher surface areas. In addition, the oxygen vacancy concentrations were significantly improved. The changes in the structures and surface properties of the solid solutions significantly affected the HCl catalytic oxidation performances. The order of the activities of various catalysts was CuO-Ce0.9La0.1O2-SiO2>CuO-Ce0.9Nd0.1O2-SiO2>CuO-Ce0.9Pr0.1O2-SiO2>CuO-CeO2-SiO2. The oxygen vacancy concentrations of the solid solutions were strongly related to their catalytic activities. However, the structures and performances of the Ce0.9M0.1O2-SiO2 catalysts showed that an increase in the number of oxygen vacancies resulted in decreased catalytic activities of the solid solutions. Kinetic studies showed that oxygen adsorption could be the rate-determining step for rare-earth-doped catalysts;a higher oxygen vacancy concentration in the solid solution led to a slower reaction rate when the volumetric flow ratio of O2 to HCl was 1. For the CuO-Ce0.9M0.1O2-SiO2 catalysts, spil over of oxygen species in the solid solution into the highly dispersed CuO interfaces was enhanced, which increased the overal reaction rate and gave high activity.