ZHOU Bai-Bin *,1,2 WEI Yong-De 1 LI Zhong-Hua 1 ( 1 Department of Applied Chemistry,Ha rbin Institute of Technology ￡?Harbin￡±￡ì￡°￡°￡°￡±￡(c)( 2 Department of Chemistry,Harbin Norm...ZHOU Bai-Bin *,1,2 WEI Yong-De 1 LI Zhong-Hua 1 ( 1 Department of Applied Chemistry,Ha rbin Institute of Technology ￡?Harbin￡±￡ì￡°￡°￡°￡±￡(c)( 2 Department of Chemistry,Harbin Normal University￡?Harbin￡±￡ì￡°￡°￡?￡°￡(c) The air-solid interface reaction of Ce,Lu with K10 H 3[Gd (SiMo 4 W￡*O￡3￡1￡(c) 2]through chemistry-heated permeation is reported for the fi rst time￡(r)The permeated complex is characterized by ICP and the result shows tha t the mini mum Ce,Lu can permeate into the inner sph ere of K 10 H ￡3 ￡?Gd ￡¨SiMo ￡′ W ￡* O ￡3￡1 ￡(c) 2]The IR ,XRD patterns give the eviden ce that after permeation the comple x still keeps the Keggin structure,howe ver,its crystal structure is different from the complex before permeation￡(r)The cond uctivity of the permeated complex has been measured with the four-electr ode method and the data show that the co nductivity of the complex after permeation is 10 6 times higher than that of the sample before permeation and reaches ￡′￡(r)84 6×10 -1 S·cm -1 ￡(r)These indicate that the permeated c omplex is a good solid electrolyte and further appli cations are also expected￡(r)展开更多
采用共沉淀法在不同母盐溶液浓度条件下合成出Gd_2Ti_2O_7:Ce纳米粒子;用XRD、SEM、TG-DTA等测试手段分析了样品的物相、形貌及发光性能;用热分析动力学计算不同升温速率下样品的活化能。结果表明:前驱体在升温过程的物相变化分3个阶段,...采用共沉淀法在不同母盐溶液浓度条件下合成出Gd_2Ti_2O_7:Ce纳米粒子;用XRD、SEM、TG-DTA等测试手段分析了样品的物相、形貌及发光性能;用热分析动力学计算不同升温速率下样品的活化能。结果表明:前驱体在升温过程的物相变化分3个阶段,用Doyle-Ozawa和Kissinger法分别对初始浓度为0.08和0.04 mol/L条件下各阶段表观活化能进行计算,其平均值为42.43、145.58、381.98 k J·mol^(-1)和51.28、161.51、446.30 k J·mol^(-1),晶粒生长活化能分别为12.58和19.54 k J·mol^(-1)。浓度为0.08 mol/L时,1173 K煅烧2 h制备出的纳米粒子表面活性较高,铈离子掺杂0.7%(摩尔分数)时发光强度最大。展开更多
La_2Ce_2O_7 nanoparticles were prepared by citric acid complexation method followed by calcination at varied temperatures. Then, supported with 4 wt% Ru, they were evaluated as the catalysts for ammonia synthesis unde...La_2Ce_2O_7 nanoparticles were prepared by citric acid complexation method followed by calcination at varied temperatures. Then, supported with 4 wt% Ru, they were evaluated as the catalysts for ammonia synthesis under conditions similar with industry. With La_2Ce_2O_7 being calcinated at 700 or 800℃, the experimental results indicate that the Ru/La_2Ce_2O_7 catalyst exhibits much higher ammonia concentration or ammonia synthesis rate than that of Ru/CeO_2 and Ru/La_2O_3. In addition, Ru/La_2Ce_2O_7 possesses high stability under over-heating test. In the absence of any promotor, ammonia concentration of Ru/La_2Ce_2O_7 catalyst approaches 14% at 450℃, GHSV of 10000 h^(-1) and pressure of 10 MPa. The rate-determining step of ammonia synthesis, dissociation of N_2 is significantly facilitated by the strong metalesupport interaction(SMSI) between Ru and La_2Ce_2O_7. Due to the interaction, La_2Ce_2O_7 tends to donate electrons to Ru,resulting in the high electron density over the surface of Ru active sites which is favorable for the dissociation of N_2. Consequently, high activity is achieved.展开更多
文摘ZHOU Bai-Bin *,1,2 WEI Yong-De 1 LI Zhong-Hua 1 ( 1 Department of Applied Chemistry,Ha rbin Institute of Technology ￡?Harbin￡±￡ì￡°￡°￡°￡±￡(c)( 2 Department of Chemistry,Harbin Normal University￡?Harbin￡±￡ì￡°￡°￡?￡°￡(c) The air-solid interface reaction of Ce,Lu with K10 H 3[Gd (SiMo 4 W￡*O￡3￡1￡(c) 2]through chemistry-heated permeation is reported for the fi rst time￡(r)The permeated complex is characterized by ICP and the result shows tha t the mini mum Ce,Lu can permeate into the inner sph ere of K 10 H ￡3 ￡?Gd ￡¨SiMo ￡′ W ￡* O ￡3￡1 ￡(c) 2]The IR ,XRD patterns give the eviden ce that after permeation the comple x still keeps the Keggin structure,howe ver,its crystal structure is different from the complex before permeation￡(r)The cond uctivity of the permeated complex has been measured with the four-electr ode method and the data show that the co nductivity of the complex after permeation is 10 6 times higher than that of the sample before permeation and reaches ￡′￡(r)84 6×10 -1 S·cm -1 ￡(r)These indicate that the permeated c omplex is a good solid electrolyte and further appli cations are also expected￡(r)
文摘采用共沉淀法在不同母盐溶液浓度条件下合成出Gd_2Ti_2O_7:Ce纳米粒子;用XRD、SEM、TG-DTA等测试手段分析了样品的物相、形貌及发光性能;用热分析动力学计算不同升温速率下样品的活化能。结果表明:前驱体在升温过程的物相变化分3个阶段,用Doyle-Ozawa和Kissinger法分别对初始浓度为0.08和0.04 mol/L条件下各阶段表观活化能进行计算,其平均值为42.43、145.58、381.98 k J·mol^(-1)和51.28、161.51、446.30 k J·mol^(-1),晶粒生长活化能分别为12.58和19.54 k J·mol^(-1)。浓度为0.08 mol/L时,1173 K煅烧2 h制备出的纳米粒子表面活性较高,铈离子掺杂0.7%(摩尔分数)时发光强度最大。
基金Project supported by National Natural Science Foundation of China(21776257)
文摘La_2Ce_2O_7 nanoparticles were prepared by citric acid complexation method followed by calcination at varied temperatures. Then, supported with 4 wt% Ru, they were evaluated as the catalysts for ammonia synthesis under conditions similar with industry. With La_2Ce_2O_7 being calcinated at 700 or 800℃, the experimental results indicate that the Ru/La_2Ce_2O_7 catalyst exhibits much higher ammonia concentration or ammonia synthesis rate than that of Ru/CeO_2 and Ru/La_2O_3. In addition, Ru/La_2Ce_2O_7 possesses high stability under over-heating test. In the absence of any promotor, ammonia concentration of Ru/La_2Ce_2O_7 catalyst approaches 14% at 450℃, GHSV of 10000 h^(-1) and pressure of 10 MPa. The rate-determining step of ammonia synthesis, dissociation of N_2 is significantly facilitated by the strong metalesupport interaction(SMSI) between Ru and La_2Ce_2O_7. Due to the interaction, La_2Ce_2O_7 tends to donate electrons to Ru,resulting in the high electron density over the surface of Ru active sites which is favorable for the dissociation of N_2. Consequently, high activity is achieved.
