Nanocrystals of Ce1-xMnxO2-δ（x=0.00,0.05,0.10,0.15,and 0.20） were synthesized by a hydrothermal reaction route.The solid solutions crystallized in a cubic fluorite structure with a particle size in the range of 11...Nanocrystals of Ce1-xMnxO2-δ（x=0.00,0.05,0.10,0.15,and 0.20） were synthesized by a hydrothermal reaction route.The solid solutions crystallized in a cubic fluorite structure with a particle size in the range of 11～15 nm.The incorporation of Mn ions in CeO2 resulted in a lattice volume reduction.Mn ions showed a mixed valence state of ＋2,＋3 and ＋4 in CeO2 lattice.An obvious red-shift of the absorption threshold edge was observed from the UV-visible spectrum.Compared with the bulk CeO2,Ce1-xMnxO2-δ nanocrystals exhibited a lower releasing oxygen temperature as indicated by TPR technique.展开更多
In this paper, the molybdenum phosphide(MoP) catalysts(TPR-MoP and TPR-MoP-Pla) were prepared by the traditional method and the RF(radio frequency) thermal plasma technique respectively and characterized by x-ray diff...In this paper, the molybdenum phosphide(MoP) catalysts(TPR-MoP and TPR-MoP-Pla) were prepared by the traditional method and the RF(radio frequency) thermal plasma technique respectively and characterized by x-ray diffraction(XRD), x-ray photoelectron spectroscopy(XPS), transmission electron microscope(TEM), hydrogen temperature-programmed desorption(H_2-TPD) and carbon monoxide temperature-programmed desorption(CO-TPD) measurements,and their catalytic performance for HAS was evaluated. The results showed that the total and C_(2+) alcohols selectivity of the catalyst after plasma treatment(TPR-MoP-Pla) were enhanced.The enhanced catalytic performance could be related to more dislocation defects and the synergistic effect between Mo^(0–2+) and Mo^(4+) valence species in the TPR-MoP-Pla catalyst. In addition, this work suggests that thermal plasma treatment can be used as a new preparation technique for the synthesis of materials with rich species.展开更多
Ceria spheres with different sizes and sulfurized products with corresponding morphology were prepared by hydro-thermal and gas-solid reaction method at 600-800℃ under CS2 atmosphere for a short time, respectively. D...Ceria spheres with different sizes and sulfurized products with corresponding morphology were prepared by hydro-thermal and gas-solid reaction method at 600-800℃ under CS2 atmosphere for a short time, respectively. Dimensional effect in preparation ofγ-Ce2S3 was firstly investigated by means of techniques such as scanning electron microscopy （SEM）, X-ray dif-fraction （XRD）, thermal gravimetric analysis （TGA） and spectrophotometer. The results showed that when ceria nanoparticles with small size were used as precursors, theγ-Ce2S3 could be prepared at the lower temperature and the badly sintered products were obtained; when ceria nanoparticles with large size were employed as precursors, pureγ-Ce2S3 was difficultly obtained even if the temperature was up to 800℃ and the products tended to keep their original size. The heat-resistance property of theγ-Ce2S3 with large size was better than the smaller one, and the pureγ-Ce2S3 prepared from precursor with small size had a good pigmen-tary performance.展开更多
基金Supported by NNSFC (Nos 20671092, 20773132, 20771101)National Basic Research Program of China (No 2007BAE08B01, 2009 CB613306)
文摘Nanocrystals of Ce1-xMnxO2-δ（x=0.00,0.05,0.10,0.15,and 0.20） were synthesized by a hydrothermal reaction route.The solid solutions crystallized in a cubic fluorite structure with a particle size in the range of 11～15 nm.The incorporation of Mn ions in CeO2 resulted in a lattice volume reduction.Mn ions showed a mixed valence state of ＋2,＋3 and ＋4 in CeO2 lattice.An obvious red-shift of the absorption threshold edge was observed from the UV-visible spectrum.Compared with the bulk CeO2,Ce1-xMnxO2-δ nanocrystals exhibited a lower releasing oxygen temperature as indicated by TPR technique.
基金the National Natural Science Foundation of China (No. 21476118)Major Projects of Inner Mongolia Natural Science Foundation (2019ZD01)+2 种基金Inner Mongolia Science & Technology Plan (Nos. 30500515330303)Inner Mongolia Major Science and Technology Project (No. 21300-5193901)Prairie Excellence Innovation and Entrepreneurial Team of Inner Mongolia (No. 12000-12102413)。
文摘In this paper, the molybdenum phosphide(MoP) catalysts(TPR-MoP and TPR-MoP-Pla) were prepared by the traditional method and the RF(radio frequency) thermal plasma technique respectively and characterized by x-ray diffraction(XRD), x-ray photoelectron spectroscopy(XPS), transmission electron microscope(TEM), hydrogen temperature-programmed desorption(H_2-TPD) and carbon monoxide temperature-programmed desorption(CO-TPD) measurements,and their catalytic performance for HAS was evaluated. The results showed that the total and C_(2+) alcohols selectivity of the catalyst after plasma treatment(TPR-MoP-Pla) were enhanced.The enhanced catalytic performance could be related to more dislocation defects and the synergistic effect between Mo^(0–2+) and Mo^(4+) valence species in the TPR-MoP-Pla catalyst. In addition, this work suggests that thermal plasma treatment can be used as a new preparation technique for the synthesis of materials with rich species.
基金Project supported by the National Natural Science Foundation of China(20961006)Inner Mongolia Natural Science Foundation(20080404MS0201)Inner Mongolia Technology Innovation and Guidance Funds
文摘Ceria spheres with different sizes and sulfurized products with corresponding morphology were prepared by hydro-thermal and gas-solid reaction method at 600-800℃ under CS2 atmosphere for a short time, respectively. Dimensional effect in preparation ofγ-Ce2S3 was firstly investigated by means of techniques such as scanning electron microscopy （SEM）, X-ray dif-fraction （XRD）, thermal gravimetric analysis （TGA） and spectrophotometer. The results showed that when ceria nanoparticles with small size were used as precursors, theγ-Ce2S3 could be prepared at the lower temperature and the badly sintered products were obtained; when ceria nanoparticles with large size were employed as precursors, pureγ-Ce2S3 was difficultly obtained even if the temperature was up to 800℃ and the products tended to keep their original size. The heat-resistance property of theγ-Ce2S3 with large size was better than the smaller one, and the pureγ-Ce2S3 prepared from precursor with small size had a good pigmen-tary performance.
