Solubilities and properties (density, conductivity and pH value) of solutions in the quaternary system Li +,K +//CO 2- 3,B 4O 2- 7-H 2O at 288 K were experimentally studied with the isothermal equilibrium method. The ...Solubilities and properties (density, conductivity and pH value) of solutions in the quaternary system Li +,K +//CO 2- 3,B 4O 2- 7-H 2O at 288 K were experimentally studied with the isothermal equilibrium method. The phase diagram of the system consisted of two invariant points E and F, five univariant curves, and four crystallization fields that belonged to K 2CO 3·3/2H 2O,Li 2 B 4O 7·3H 2O, K 2 B 4O 7 ·4H 2O and Li 2CO 3. The composition of the solution corresponding to E was w(CO 2- 3)=2.27 %, w(B 4O 2- 7) =6.05 %, w(K + ) =4.30%,w(Li + )=0.30 % and the equilibrium solids were Li 2 B 4O 7· 3H 2O+K 2 B 4O 7·4H 2O+Li 2CO 3;The composition of the solution for F was w(CO 2- 3) =22.45%,w(B 4O 2- 7)=1.88%,w(K + )=29.96%,w(Li + )=0.03% and the equilibrium solids were K 2CO 3·3/2H 2O+ K 2 B 4O 7·4H 2O+Li 2CO 3. K 2CO 3 possesses strong salting-out effect on K 2 B 4O 7,Li 2CO 3 and Li 2 B 4O 7.展开更多
Compound [Co 3(BTC)(HBTC)(H 2BTC)(C 2H 4O 2) 3]·3(DMF)·6(H 3O) was synthesized under mild conditions and its crystal structure was determined by using single crystal X-ray diffraction. The crystal structure ...Compound [Co 3(BTC)(HBTC)(H 2BTC)(C 2H 4O 2) 3]·3(DMF)·6(H 3O) was synthesized under mild conditions and its crystal structure was determined by using single crystal X-ray diffraction. The crystal structure was solved by direct method and refined by full-matrix least-square method. The crystal is monoclinic and belongs to space group Cc with a=2.645 3(5) nm, b= 1.670 4(3) nm, c=1\^821 6(4) nm, β=128.16(3) °, V=6.329(2) nm 3, Z=2 , D c=20.200 Mg/m 3, M r= 1 314.744, μ=10.274 mm -1, F(000) =38 226, GOF=0.99, R=0.094 1, ωR=0.257 3.展开更多
In this study, Co3O4@CeO2 core@shell nanowires were successfully prepared via thermal decomposition of Co（CO3）0.5（OH）.0.11H2O@CeO2 core@shell nanowire precursors. As a CO oxidation catalyst, Co3O4@CeO2 shows remar...In this study, Co3O4@CeO2 core@shell nanowires were successfully prepared via thermal decomposition of Co（CO3）0.5（OH）.0.11H2O@CeO2 core@shell nanowire precursors. As a CO oxidation catalyst, Co3O4@CeO2 shows remarkably enhanced catalytic performance compared to Co3O4 nanowires and CeO2 nanoparticles （NPs）, indicating obvious synergistic effects between the two components. It also suggests that the CeO2 shell coating can effectively prevent Co3O4 nanowires from agglomerating, hence effecting a substantial improvement in the structural stability of the Co3O4 catalyst. Furthermore, the fabrication of the welbdisperse4 core@shell structure results in a maximized interface area between Co3O4 and CeO2, as well as a reduced Co3O4 size, which may be responsible for the enhanced catalytic activity of Co3O4@CeO2. Further examination revealed that CO oxidation may occur at the interface of Co3O4 and CeO2. The influence of calcination temperatures and the component ratio between Co3O4 and CeO2 were then investigated in detail to determine the catalytic performance of Co3O4@CeO2 core@shell nanowires, the best of which was obtained by calcination at 250 ℃ for 3 h with a Ce molar concentration of about 38.5%. This sample achieved 100% CO conversion at a reduced temperature of 160 ℃. More importantly, more than 2.5 g of the Co3O4@CeO2 core@shell nanowires were produced in one pot by this simple process, which may be beneficial for practical applications as automobile-exhaust gas-treatment catalysts.展开更多
文摘Solubilities and properties (density, conductivity and pH value) of solutions in the quaternary system Li +,K +//CO 2- 3,B 4O 2- 7-H 2O at 288 K were experimentally studied with the isothermal equilibrium method. The phase diagram of the system consisted of two invariant points E and F, five univariant curves, and four crystallization fields that belonged to K 2CO 3·3/2H 2O,Li 2 B 4O 7·3H 2O, K 2 B 4O 7 ·4H 2O and Li 2CO 3. The composition of the solution corresponding to E was w(CO 2- 3)=2.27 %, w(B 4O 2- 7) =6.05 %, w(K + ) =4.30%,w(Li + )=0.30 % and the equilibrium solids were Li 2 B 4O 7· 3H 2O+K 2 B 4O 7·4H 2O+Li 2CO 3;The composition of the solution for F was w(CO 2- 3) =22.45%,w(B 4O 2- 7)=1.88%,w(K + )=29.96%,w(Li + )=0.03% and the equilibrium solids were K 2CO 3·3/2H 2O+ K 2 B 4O 7·4H 2O+Li 2CO 3. K 2CO 3 possesses strong salting-out effect on K 2 B 4O 7,Li 2CO 3 and Li 2 B 4O 7.
文摘Compound [Co 3(BTC)(HBTC)(H 2BTC)(C 2H 4O 2) 3]·3(DMF)·6(H 3O) was synthesized under mild conditions and its crystal structure was determined by using single crystal X-ray diffraction. The crystal structure was solved by direct method and refined by full-matrix least-square method. The crystal is monoclinic and belongs to space group Cc with a=2.645 3(5) nm, b= 1.670 4(3) nm, c=1\^821 6(4) nm, β=128.16(3) °, V=6.329(2) nm 3, Z=2 , D c=20.200 Mg/m 3, M r= 1 314.744, μ=10.274 mm -1, F(000) =38 226, GOF=0.99, R=0.094 1, ωR=0.257 3.
基金Research Project from Department of Science and Technology of Shandong Province(2012GGA01012)Scientific ResearchFoundation for the Returned Overseas Chinese Scholars of State Education Ministry(2004-527)
基金This work was supported by the financial aid from the National Natural Science Foundation of China （Nos. 91122030, 51272249, 21210001, 21221061 and 21401186）, and the National Key Basic Research Program of China （No. 2014CB643802）.
文摘In this study, Co3O4@CeO2 core@shell nanowires were successfully prepared via thermal decomposition of Co（CO3）0.5（OH）.0.11H2O@CeO2 core@shell nanowire precursors. As a CO oxidation catalyst, Co3O4@CeO2 shows remarkably enhanced catalytic performance compared to Co3O4 nanowires and CeO2 nanoparticles （NPs）, indicating obvious synergistic effects between the two components. It also suggests that the CeO2 shell coating can effectively prevent Co3O4 nanowires from agglomerating, hence effecting a substantial improvement in the structural stability of the Co3O4 catalyst. Furthermore, the fabrication of the welbdisperse4 core@shell structure results in a maximized interface area between Co3O4 and CeO2, as well as a reduced Co3O4 size, which may be responsible for the enhanced catalytic activity of Co3O4@CeO2. Further examination revealed that CO oxidation may occur at the interface of Co3O4 and CeO2. The influence of calcination temperatures and the component ratio between Co3O4 and CeO2 were then investigated in detail to determine the catalytic performance of Co3O4@CeO2 core@shell nanowires, the best of which was obtained by calcination at 250 ℃ for 3 h with a Ce molar concentration of about 38.5%. This sample achieved 100% CO conversion at a reduced temperature of 160 ℃. More importantly, more than 2.5 g of the Co3O4@CeO2 core@shell nanowires were produced in one pot by this simple process, which may be beneficial for practical applications as automobile-exhaust gas-treatment catalysts.
