The technological process of preparation of colloid Sb 2O 5 by oxidation of Sb 2O 3 with hydrogen peroxide using borax as a stabilizer has been investigated. The optimum preparation conditions selected by orthogonal f...The technological process of preparation of colloid Sb 2O 5 by oxidation of Sb 2O 3 with hydrogen peroxide using borax as a stabilizer has been investigated. The optimum preparation conditions selected by orthogonal factorization method as follows m (H 2 O)∶ m (Sb 2 O 3 )=7 5∶1, n (H 2 O 2 )∶ n (Sb 2 O 3 )=3∶1, m (Na 2 B 4 O 7 ·10H 2 O)∶ m (Sb 2 O 3 )=1∶10, 95 ℃, 1 5 h. The conversion of Sb 2 O 3 >95%, light transmittance of colloid >85% and the average diameter of Sb 2 O 5 particles was 50 nm. The colloid Sb 2 O 5 prepared was storage stable without coagulation for more than one year.展开更多
The catalytic ammoxidation of ethane with oxygen and ammonia was investigated over a series(Sb2O3) promoted ion-exchanged Co-ZSM-5 zeolites(Sb2O3/Co-ZSM-5).The introduction of appropriate amount of Sb2O3 can considera...The catalytic ammoxidation of ethane with oxygen and ammonia was investigated over a series(Sb2O3) promoted ion-exchanged Co-ZSM-5 zeolites(Sb2O3/Co-ZSM-5).The introduction of appropriate amount of Sb2O3 can considerably improve the conversion of ethane,suppress the formation of COx,and increase the total C2 selectivity to acetonitrile and ethylene.Among them,the sample with 5% Sb2O3 loading（in mass fraction） shows a 68.4% ethane conversion at 550 ℃, a 51.6% selectivity to acetonitrile and a 31.7% selectivity to ethylene,and a 35.3% yield of acetonitrile were obtained,which is to our knowledge the highest ever reported for the direct ammoxidation of ethane.展开更多
PdAuIr/C-Sb2O5·SnO2electrocatalysts with Pd∶Au∶Ir molar ratios of 90∶5∶5,70∶20∶10 and 50∶45∶5 were prepared by borohydride reduction method.These electrocatalysts were characterized by EDX,X-ray diffracti...PdAuIr/C-Sb2O5·SnO2electrocatalysts with Pd∶Au∶Ir molar ratios of 90∶5∶5,70∶20∶10 and 50∶45∶5 were prepared by borohydride reduction method.These electrocatalysts were characterized by EDX,X-ray diffraction,transmission electron microscopy and the catalytic activity toward formic acid electro-oxidation in acid medium investigated by cyclic voltammetry(CV),chroamperometry(CA)and tests on direct formic acid fuel cell(DFAFC)at 100℃.X-ray diffractograms of PdAuIr/C-Sb2O5·SnO2electrocatalysts showed the presence of Pd fcc phase,Pd-Au fcc alloys,carbon and ATO phases,while Ir phases were not observed.TEM micrographs and histograms indicated that the nanoparticles were not well dispersed on the support and some agglomerates.The cyclic voltammetry and chroamperometry studies showed that PdAuIr/C-Sb2O5·SnO2(50∶45∶5)had superior performance toward formic acid electro-oxidation at 25℃compared to PdAuIr/C-Sb2O5·SnO2(70∶20∶10),PdAuIr/C-Sb2O5·SnO2(90∶5∶5)and Pd/C-Sb2O5·SnO2electrocatalysts.The experiments in a single DFAFC also showed that all PdAuIr/C-Sb2O5·SnO2electrocatalysts exhibited higher performance for formic acid oxidation in comparison with Pd/C-Sb2O5·SnO2electrocatalysts,however PdAuIr/C-Sb2O5·SnO2(90∶5∶5)had superior performance.These results indicated that the addition of Au and Ir to Pd favor the electro-oxidation of formic acid,which could be attributed to the bifunctional mechanism(the presence of ATO,Au and Ir oxides species)associated to the electronic effect(Pd-Au fcc alloys).展开更多
In this paper, chemical mechanical planarization （CMP） of amorphous Ge2Sb2Te5 （a-GST） in acidic H2O2 slurry is investigated. It was found that the removal rate of a-GST is strongly dependent on H2O2 concentration ...In this paper, chemical mechanical planarization （CMP） of amorphous Ge2Sb2Te5 （a-GST） in acidic H2O2 slurry is investigated. It was found that the removal rate of a-GST is strongly dependent on H2O2 concentration and gradually increases with the increase in H2O2 concentration, but the static etch rate first increases and then slowly decreases with the increase in H2O2 concentration. To understand the chemical reaction behavior of H2O2 on the a-GST surface, the potentiodynamic polarization curve, surface morphology and cross-section of a-GST immersed in acidic slurry are measured and the results reveal that a-GST exhibits a from active to passive behavior for from low to high concentration of H2O2. Finally, a possible removal mechanism of a-GST in different concentrations of H2O2 in the acidic slurry is described.展开更多
The microwave dielectric properties of ZrO2-SnO2-TiO2 （ZST） system ceramics were studied as a function of the amount of Sb2O5 dopant. With the addition of 0-0.5% Sb2O5（molar ratio）, the substitution of Ti4^＋ ions...The microwave dielectric properties of ZrO2-SnO2-TiO2 （ZST） system ceramics were studied as a function of the amount of Sb2O5 dopant. With the addition of 0-0.5% Sb2O5（molar ratio）, the substitution of Ti4^＋ ions with Sb^5＋ ions decreased the sintering temperature and increased the quality factor Q due to the reduction of oxygen vacancies, When the amount of Sb^5＋ increased further （above 0.5%）, Q was decreased by increasing the electron concentration. When the system doped with 0.5% Sb2O5 was sintered at 1 150℃ for 6 h, the relative dielectric constant ε, Qf0, and the temperature coefficient of resonant frequency （TCF） were 38.46, 44 500 GHz, 20.0×10^-6/℃, respectively, at 6 GHz,展开更多
文摘The technological process of preparation of colloid Sb 2O 5 by oxidation of Sb 2O 3 with hydrogen peroxide using borax as a stabilizer has been investigated. The optimum preparation conditions selected by orthogonal factorization method as follows m (H 2 O)∶ m (Sb 2 O 3 )=7 5∶1, n (H 2 O 2 )∶ n (Sb 2 O 3 )=3∶1, m (Na 2 B 4 O 7 ·10H 2 O)∶ m (Sb 2 O 3 )=1∶10, 95 ℃, 1 5 h. The conversion of Sb 2 O 3 >95%, light transmittance of colloid >85% and the average diameter of Sb 2 O 5 particles was 50 nm. The colloid Sb 2 O 5 prepared was storage stable without coagulation for more than one year.
文摘The catalytic ammoxidation of ethane with oxygen and ammonia was investigated over a series(Sb2O3) promoted ion-exchanged Co-ZSM-5 zeolites(Sb2O3/Co-ZSM-5).The introduction of appropriate amount of Sb2O3 can considerably improve the conversion of ethane,suppress the formation of COx,and increase the total C2 selectivity to acetonitrile and ethylene.Among them,the sample with 5% Sb2O3 loading（in mass fraction） shows a 68.4% ethane conversion at 550 ℃, a 51.6% selectivity to acetonitrile and a 31.7% selectivity to ethylene,and a 35.3% yield of acetonitrile were obtained,which is to our knowledge the highest ever reported for the direct ammoxidation of ethane.
基金the Laboratório de Microscopia do Centro de Ciências e Tecnologia de Materiais(CCTM) by TEM measurements,FAPESP(2011/18246-0,2012/03516-5) and CNPQ(150639/2013-9)for the financial support
文摘PdAuIr/C-Sb2O5·SnO2electrocatalysts with Pd∶Au∶Ir molar ratios of 90∶5∶5,70∶20∶10 and 50∶45∶5 were prepared by borohydride reduction method.These electrocatalysts were characterized by EDX,X-ray diffraction,transmission electron microscopy and the catalytic activity toward formic acid electro-oxidation in acid medium investigated by cyclic voltammetry(CV),chroamperometry(CA)and tests on direct formic acid fuel cell(DFAFC)at 100℃.X-ray diffractograms of PdAuIr/C-Sb2O5·SnO2electrocatalysts showed the presence of Pd fcc phase,Pd-Au fcc alloys,carbon and ATO phases,while Ir phases were not observed.TEM micrographs and histograms indicated that the nanoparticles were not well dispersed on the support and some agglomerates.The cyclic voltammetry and chroamperometry studies showed that PdAuIr/C-Sb2O5·SnO2(50∶45∶5)had superior performance toward formic acid electro-oxidation at 25℃compared to PdAuIr/C-Sb2O5·SnO2(70∶20∶10),PdAuIr/C-Sb2O5·SnO2(90∶5∶5)and Pd/C-Sb2O5·SnO2electrocatalysts.The experiments in a single DFAFC also showed that all PdAuIr/C-Sb2O5·SnO2electrocatalysts exhibited higher performance for formic acid oxidation in comparison with Pd/C-Sb2O5·SnO2electrocatalysts,however PdAuIr/C-Sb2O5·SnO2(90∶5∶5)had superior performance.These results indicated that the addition of Au and Ir to Pd favor the electro-oxidation of formic acid,which could be attributed to the bifunctional mechanism(the presence of ATO,Au and Ir oxides species)associated to the electronic effect(Pd-Au fcc alloys).
基金Project supported by the National Basic Research Program of China (Grant Nos. 2010CB934300, 2011CBA00607, and 2011CB9328004)the National Integrate Circuit Research Program of China (Grant No. 2009ZX02023-003)+2 种基金the National Natural Science Foundation of China (Grant Nos. 60906004, 60906003,61006087, 61076121, 61176122, and 61106001)the Science and Technology Council of Shanghai, China (Grant Nos. 11DZ2261000 and 11QA1407800)the Chinese Academy of Sciences (Grant No. 20110490761)
文摘In this paper, chemical mechanical planarization （CMP） of amorphous Ge2Sb2Te5 （a-GST） in acidic H2O2 slurry is investigated. It was found that the removal rate of a-GST is strongly dependent on H2O2 concentration and gradually increases with the increase in H2O2 concentration, but the static etch rate first increases and then slowly decreases with the increase in H2O2 concentration. To understand the chemical reaction behavior of H2O2 on the a-GST surface, the potentiodynamic polarization curve, surface morphology and cross-section of a-GST immersed in acidic slurry are measured and the results reveal that a-GST exhibits a from active to passive behavior for from low to high concentration of H2O2. Finally, a possible removal mechanism of a-GST in different concentrations of H2O2 in the acidic slurry is described.
基金Supported by Natural Science Foundation of Tianjin (No.06YFJMJC01000) the High Technique Research and Development Pro-gram of China (No.2001AA325110).
文摘The microwave dielectric properties of ZrO2-SnO2-TiO2 （ZST） system ceramics were studied as a function of the amount of Sb2O5 dopant. With the addition of 0-0.5% Sb2O5（molar ratio）, the substitution of Ti4^＋ ions with Sb^5＋ ions decreased the sintering temperature and increased the quality factor Q due to the reduction of oxygen vacancies, When the amount of Sb^5＋ increased further （above 0.5%）, Q was decreased by increasing the electron concentration. When the system doped with 0.5% Sb2O5 was sintered at 1 150℃ for 6 h, the relative dielectric constant ε, Qf0, and the temperature coefficient of resonant frequency （TCF） were 38.46, 44 500 GHz, 20.0×10^-6/℃, respectively, at 6 GHz,
