研究了甲醇制丙烯(MTP)催化剂经过多周期反应后失活的本质原因,据此提出了一种简便易行的催化剂再生方法,即二次晶化法,并将其应用到失活MTP催化剂的再生中。采用X射线衍射(XRD)、X射线荧光光谱(XRF)、X射线光电子能谱(XPS)、N_2吸附、^...研究了甲醇制丙烯(MTP)催化剂经过多周期反应后失活的本质原因,据此提出了一种简便易行的催化剂再生方法,即二次晶化法,并将其应用到失活MTP催化剂的再生中。采用X射线衍射(XRD)、X射线荧光光谱(XRF)、X射线光电子能谱(XPS)、N_2吸附、^(27)Al魔角旋转固体核磁共振(^(27)Al MAS NMR)、NH_3程序升温脱附(NH_3-TPD)、吡啶吸附红外(Py-IR)光谱等测试技术对再生前后HZSM-5分子筛催化剂的晶体结构、硅铝比、织构性质、酸性质等进行了表征。并在常压(甲醇分压为30 k Pa)、反应温度为470°C、甲醇质量空速(WHSV)为1 h^(-1)的条件下,研究了再生前后HZSM-5分子筛催化剂的催化性能。结果表明,分子筛晶体结构被破坏、活性位流失是多周期反应后HZSM-5分子筛催化剂活性下降的主要原因。经过二次晶化再生后,催化剂的相对结晶度、比表面积、孔容和酸量都明显提高,晶体结构和活性位得到了有效修复,再生催化剂在MTP反应中重新表现出优异的甲醇转化能力和丙烯选择性。展开更多
Efficient composite semiconductor photocatalysts are highly desirable for the visible-light-driven degradation of organic pollutants. In this study, Bi24O31Cl10 photocatalyst was prepared via a hydrothermal method and...Efficient composite semiconductor photocatalysts are highly desirable for the visible-light-driven degradation of organic pollutants. In this study, Bi24O31Cl10 photocatalyst was prepared via a hydrothermal method and modified with Pt nanoparticles (NPs) through a facile deposition procedure. The composite photocatalyst was characterized by X-ray diffraction, transmission electronic microscopy, X-ray photoelectron spectroscopy, UV-vis diffusion reflectance spectroscopy, photoluminescence spectroscopy, and electron spin resonance. The 1.0 wt% Pt/Bi24O31Cl10 photocatalyst showed the highest activity for the degradation of methyl orange under visible light (source: 300 W Xe lamp coupled with a UV-cutoff filter), and the photocatalytic degradation efficiency improved about 2.2 times compared to that of pure Bi24O31Cl10. The composite photocatalyst could maintain most of its activity after four runs of the photocatalytic experimental cycle. This study could provide a novel insight for the modification of other desirable semiconductor materials to achieve high photocatalytic activities.展开更多
文摘研究了甲醇制丙烯(MTP)催化剂经过多周期反应后失活的本质原因,据此提出了一种简便易行的催化剂再生方法,即二次晶化法,并将其应用到失活MTP催化剂的再生中。采用X射线衍射(XRD)、X射线荧光光谱(XRF)、X射线光电子能谱(XPS)、N_2吸附、^(27)Al魔角旋转固体核磁共振(^(27)Al MAS NMR)、NH_3程序升温脱附(NH_3-TPD)、吡啶吸附红外(Py-IR)光谱等测试技术对再生前后HZSM-5分子筛催化剂的晶体结构、硅铝比、织构性质、酸性质等进行了表征。并在常压(甲醇分压为30 k Pa)、反应温度为470°C、甲醇质量空速(WHSV)为1 h^(-1)的条件下,研究了再生前后HZSM-5分子筛催化剂的催化性能。结果表明,分子筛晶体结构被破坏、活性位流失是多周期反应后HZSM-5分子筛催化剂活性下降的主要原因。经过二次晶化再生后,催化剂的相对结晶度、比表面积、孔容和酸量都明显提高,晶体结构和活性位得到了有效修复,再生催化剂在MTP反应中重新表现出优异的甲醇转化能力和丙烯选择性。
基金supported by the National Natural Science Foundation of China(51572295,21273285 and 21003157)Beijing Nova Program(2008B76)Science Foundation of China University of Petroleum Beijing(KYJJ2012-06-20 and 2462016YXBS05)~~
文摘Efficient composite semiconductor photocatalysts are highly desirable for the visible-light-driven degradation of organic pollutants. In this study, Bi24O31Cl10 photocatalyst was prepared via a hydrothermal method and modified with Pt nanoparticles (NPs) through a facile deposition procedure. The composite photocatalyst was characterized by X-ray diffraction, transmission electronic microscopy, X-ray photoelectron spectroscopy, UV-vis diffusion reflectance spectroscopy, photoluminescence spectroscopy, and electron spin resonance. The 1.0 wt% Pt/Bi24O31Cl10 photocatalyst showed the highest activity for the degradation of methyl orange under visible light (source: 300 W Xe lamp coupled with a UV-cutoff filter), and the photocatalytic degradation efficiency improved about 2.2 times compared to that of pure Bi24O31Cl10. The composite photocatalyst could maintain most of its activity after four runs of the photocatalytic experimental cycle. This study could provide a novel insight for the modification of other desirable semiconductor materials to achieve high photocatalytic activities.
