Alkaline earth benzoates were synthesized using hydrothermal reaction. The complexes were characterized by elemental analysis, IR, X ray powder diffraction. All of them are monoclinic and have layered structure. The ...Alkaline earth benzoates were synthesized using hydrothermal reaction. The complexes were characterized by elemental analysis, IR, X ray powder diffraction. All of them are monoclinic and have layered structure. The mechanism of thermal decomposition of alkaline earth benzoates was studied by using TG, DTA, IR and gas chromatography mass spectrometry. The thermal decomposition of alkaline earth benzoates in nitrogen proceeded in one or two stages: they decomposed to form MCO 3 (M=Ca,Sr,Ba) or MgO and organic compounds, respectively. The organic compounds obtained from decomposition reaction are mainly benzophenone, triphenylmethane and so on.展开更多
The rare earth metal benzoates were synthesized using hydrothermal reaction. The complexes were characterized by elemental analysis, IR and X-ray powder diffraction. They can be represented by general formula RE (C6H5...The rare earth metal benzoates were synthesized using hydrothermal reaction. The complexes were characterized by elemental analysis, IR and X-ray powder diffraction. They can be represented by general formula RE (C6H5COO)(3)(RE = La, Nd, Sm, Eu, Gd, Dy and Er). All of them are monoclinic and have layered structure. The mechanism of thermal decomposition of rare earth metal benzoates was studied by using TG, DTA, IR, and gas chromatography-mass spectrometry. The thermal decomposition of the rare earth benzoates in nitrogen proceeded in two stages; firstly it decomposed to form RE2O(CO3)(2) and organic compounds, then RE2O(CO3)(2) decomposed further to form rare earth metal oxides and carbon dioxide. The organic compounds obtained from the first step of the reaction are mainly benzophenone, 9,10-anthraquinone, 1, 3-Diphenylisobenzofuran and so on.展开更多
Eleven rare earth salts of 3-nitro-1, 2 , 4-triazol-5-one (NTO) was prepared by using aqueous solutions of lithium salt of NTO and corresponding rare earth nitrates. The formulae of these salts are determined as RE(NT...Eleven rare earth salts of 3-nitro-1, 2 , 4-triazol-5-one (NTO) was prepared by using aqueous solutions of lithium salt of NTO and corresponding rare earth nitrates. The formulae of these salts are determined as RE(NTO)3. nH2O, where RE is Y, La, Ce, Pr, Nd, Sm, Eu, Gd,Tb, Dy or Yb, and n is 6, 7, 7, 7, 8, 7, 7, 7, 5, 5 and 6 correspondingly. Their thermal decomposition mechanism was studied by using DSC, TG-DTG and FT-IR techniques under linearly increasing temperature.展开更多
The pure phases of alkaline earth molybdates MMoO 4, where M=Mg, Ca, Sr or Ba, were synthesized via the calcination of the related citrato oxomolybdate complexes. The mixed metal oxides can be highly dispersed at the...The pure phases of alkaline earth molybdates MMoO 4, where M=Mg, Ca, Sr or Ba, were synthesized via the calcination of the related citrato oxomolybdate complexes. The mixed metal oxides can be highly dispersed at the atomic level due to the existence of uniform citrato oxomolybdenum precursors in definite composition. The complexing effect helps to produce the fine-grained oxides with particle size in the ultrafine scale(<100 nm) at heat-treatment temperatures below 500 ℃. The structures of the precursor complexes and the finally heat-treated particles were studied by means of IR, XRD, DSC, DTA and TG techniques. The morphologies of the particles were observed by using the SEM technique. The average particle sizes were calculated to be in the range of 30_50 nm based on X-ray diffraction line-broadening and SEM images, indicating the poor conglomeration of crystallite at low temperatures.展开更多
Development of active and non-noble metal-based catalyst for H2 production via NH3 decomposition is crucial for the implementation of NH3 as a H2 carrier.Co-based catalysts have received increasing attention because o...Development of active and non-noble metal-based catalyst for H2 production via NH3 decomposition is crucial for the implementation of NH3 as a H2 carrier.Co-based catalysts have received increasing attention because of its high intrinsic activity and moderate cost.In this work,we examined the effect of BaNH,CaNH and Mg3 N2 on the catalytic activity of Co in the NH3 decomposition reaction.The H2 formation rate ranks the order as Co-BaNH>Co-CaNH>Co-Mg3 N2≈Co/CNTs within a reaction temperature range of 300-550℃.It is worth pointing out that the H2 formation rate of Co-BaNH at 500℃reaches20 mmolH2 gcat-1 min-1,which is comparable to those of the active Ru/Al2 O3(ca.17 mmolH2 gcat-1 min1)and Ru/AC(21 mmolH2 gcat-1 min-1)catalysts under the similar reaction conditions.In-depth research shows that Co-BaNH exhibits an obviously higher intrinsic activity and much lower Ea(46.2 kJ mol-1)than other Co-based catalysts,suggesting that BaNH may play a different role from CaNH,Mg3 N2 and CNTs during the catalytic process.Combined results of XRD,Ar-TPD and XAS show that a[Co-N-Ba]-like intermediate species is likely formed at the interface of Co metal and BaNH,which may lead to a more energy-efficient reaction pathway than that of neat Co metal for NH3 decomposition.展开更多
通过热分析法对碱土金属四苯硼盐的脱水及氧化分解过程进行了研究,给出了脱水温度、氧化分解温度及其随阳离子半径的变化规律;确定了碱土金属四苯硼盐的氧化分解反应为;M(BPh_4)_2(c)+60m(g)→M(BO_2)_2(c)+48CO_2(g)+20H_2O(g)(其中 M ...通过热分析法对碱土金属四苯硼盐的脱水及氧化分解过程进行了研究,给出了脱水温度、氧化分解温度及其随阳离子半径的变化规律;确定了碱土金属四苯硼盐的氧化分解反应为;M(BPh_4)_2(c)+60m(g)→M(BO_2)_2(c)+48CO_2(g)+20H_2O(g)(其中 M 为 Mg、Ca、Sr、Ba).通过离子模型对碱土金属四苯硼盐的氧化热稳定性进行了讨论.展开更多
文摘Alkaline earth benzoates were synthesized using hydrothermal reaction. The complexes were characterized by elemental analysis, IR, X ray powder diffraction. All of them are monoclinic and have layered structure. The mechanism of thermal decomposition of alkaline earth benzoates was studied by using TG, DTA, IR and gas chromatography mass spectrometry. The thermal decomposition of alkaline earth benzoates in nitrogen proceeded in one or two stages: they decomposed to form MCO 3 (M=Ca,Sr,Ba) or MgO and organic compounds, respectively. The organic compounds obtained from decomposition reaction are mainly benzophenone, triphenylmethane and so on.
文摘The rare earth metal benzoates were synthesized using hydrothermal reaction. The complexes were characterized by elemental analysis, IR and X-ray powder diffraction. They can be represented by general formula RE (C6H5COO)(3)(RE = La, Nd, Sm, Eu, Gd, Dy and Er). All of them are monoclinic and have layered structure. The mechanism of thermal decomposition of rare earth metal benzoates was studied by using TG, DTA, IR, and gas chromatography-mass spectrometry. The thermal decomposition of the rare earth benzoates in nitrogen proceeded in two stages; firstly it decomposed to form RE2O(CO3)(2) and organic compounds, then RE2O(CO3)(2) decomposed further to form rare earth metal oxides and carbon dioxide. The organic compounds obtained from the first step of the reaction are mainly benzophenone, 9,10-anthraquinone, 1, 3-Diphenylisobenzofuran and so on.
文摘Eleven rare earth salts of 3-nitro-1, 2 , 4-triazol-5-one (NTO) was prepared by using aqueous solutions of lithium salt of NTO and corresponding rare earth nitrates. The formulae of these salts are determined as RE(NTO)3. nH2O, where RE is Y, La, Ce, Pr, Nd, Sm, Eu, Gd,Tb, Dy or Yb, and n is 6, 7, 7, 7, 8, 7, 7, 7, 5, 5 and 6 correspondingly. Their thermal decomposition mechanism was studied by using DSC, TG-DTG and FT-IR techniques under linearly increasing temperature.
基金the Foundation of the Ministry of Science and Technology of China(No.G19990 2 2 4 0 8and0 0 1CB10 890 6 )
文摘The pure phases of alkaline earth molybdates MMoO 4, where M=Mg, Ca, Sr or Ba, were synthesized via the calcination of the related citrato oxomolybdate complexes. The mixed metal oxides can be highly dispersed at the atomic level due to the existence of uniform citrato oxomolybdenum precursors in definite composition. The complexing effect helps to produce the fine-grained oxides with particle size in the ultrafine scale(<100 nm) at heat-treatment temperatures below 500 ℃. The structures of the precursor complexes and the finally heat-treated particles were studied by means of IR, XRD, DSC, DTA and TG techniques. The morphologies of the particles were observed by using the SEM technique. The average particle sizes were calculated to be in the range of 30_50 nm based on X-ray diffraction line-broadening and SEM images, indicating the poor conglomeration of crystallite at low temperatures.
基金financial supports from the Project of the National Natural Science Foundation of China(Grant Nos.21633011and 21872137)“Transformational Technologies for Clean Energy and Demonstration”+2 种基金Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDA21000000)Youth Innovation Promotion Association CAS(No.2018213)the Shanghai Synchrotron Radiation Facility(SSRF)for providing the beam time。
文摘Development of active and non-noble metal-based catalyst for H2 production via NH3 decomposition is crucial for the implementation of NH3 as a H2 carrier.Co-based catalysts have received increasing attention because of its high intrinsic activity and moderate cost.In this work,we examined the effect of BaNH,CaNH and Mg3 N2 on the catalytic activity of Co in the NH3 decomposition reaction.The H2 formation rate ranks the order as Co-BaNH>Co-CaNH>Co-Mg3 N2≈Co/CNTs within a reaction temperature range of 300-550℃.It is worth pointing out that the H2 formation rate of Co-BaNH at 500℃reaches20 mmolH2 gcat-1 min-1,which is comparable to those of the active Ru/Al2 O3(ca.17 mmolH2 gcat-1 min1)and Ru/AC(21 mmolH2 gcat-1 min-1)catalysts under the similar reaction conditions.In-depth research shows that Co-BaNH exhibits an obviously higher intrinsic activity and much lower Ea(46.2 kJ mol-1)than other Co-based catalysts,suggesting that BaNH may play a different role from CaNH,Mg3 N2 and CNTs during the catalytic process.Combined results of XRD,Ar-TPD and XAS show that a[Co-N-Ba]-like intermediate species is likely formed at the interface of Co metal and BaNH,which may lead to a more energy-efficient reaction pathway than that of neat Co metal for NH3 decomposition.
文摘通过热分析法对碱土金属四苯硼盐的脱水及氧化分解过程进行了研究,给出了脱水温度、氧化分解温度及其随阳离子半径的变化规律;确定了碱土金属四苯硼盐的氧化分解反应为;M(BPh_4)_2(c)+60m(g)→M(BO_2)_2(c)+48CO_2(g)+20H_2O(g)(其中 M 为 Mg、Ca、Sr、Ba).通过离子模型对碱土金属四苯硼盐的氧化热稳定性进行了讨论.
