采用溶胶-凝胶法制备了不同稀土金属和过渡金属离子为助催化剂的SiO_2负载型磷钼酸(HPMo)催化剂M-HPMo/SiO_2(M=Eu、La、Ni、Co),研究了此催化剂在模拟柴油的催化氧化脱硫反应中的性能。使用X射线衍射(XRD)、傅里叶变换-红外光谱FT-IR...采用溶胶-凝胶法制备了不同稀土金属和过渡金属离子为助催化剂的SiO_2负载型磷钼酸(HPMo)催化剂M-HPMo/SiO_2(M=Eu、La、Ni、Co),研究了此催化剂在模拟柴油的催化氧化脱硫反应中的性能。使用X射线衍射(XRD)、傅里叶变换-红外光谱FT-IR、N2吸附-脱附等分析手段对催化剂的结构进行了表征。结果表明,稀土金属和过渡金属离子的加入保持了磷钼酸的Keggin结构,并促进了磷钼酸活性中心在SiO_2表面的分布,稀土元素催化助剂Eu在反应中的助催化作用最为明显,Eu-HPMo/SiO_2有较高的催化活性。在催化剂用量为0.1 g、反应温度为50℃、n(H_2O_2)/n(S)=3、反应时间60 min,催化剂Eu-HPMo/SiO_2对DBT的脱除率为99.2%。该脱硫反应为表观一级反应,反应表观活化能为51.16±5.79 k J/mol,指前因子A=6154±697。展开更多
This paper reviewed the effect of powder characteristics and additives including metals,rare earth oxides,and ZrO2 on nitridation of Si powder.The decrease of particle size of Si powder increased nitridation.Most of m...This paper reviewed the effect of powder characteristics and additives including metals,rare earth oxides,and ZrO2 on nitridation of Si powder.The decrease of particle size of Si powder increased nitridation.Most of metal additives inhibited nitridation,while some metal additives such as Fe,Cu,Cr,and Ca increased nitrida—tion.Otherwise,the addition of metals might lead to the degradation of physical and mechanical properties of Si3N4.All the rare earth oxides,especially CeO2 and Eu2O3,showed nitridation enhancing effect.In addition,ZrO2 with small particle size showed a stronger enhancing effect.展开更多
金属加工助剂是金属加工生产过程中必不可少的化工产品,其组成复杂,易形成螯合物干扰成分分析。该文利用傅立叶变换离子回旋共振质谱(Fourier transform ion cyclotron resonance mass spectrometry,FT-ICR MS)技术的高分辨性能,结合电...金属加工助剂是金属加工生产过程中必不可少的化工产品,其组成复杂,易形成螯合物干扰成分分析。该文利用傅立叶变换离子回旋共振质谱(Fourier transform ion cyclotron resonance mass spectrometry,FT-ICR MS)技术的高分辨性能,结合电感耦合等离子体质谱(ICP-MS)、红外光谱(IR)和核磁共振谱(NMR)对一种含未知成分的金属加工助剂进行成分分析。结果表明,该金属加工助剂中含有柠檬酸钠、乙二胺四乙酸(EDTA)与金属铋螯合物。该方法简便、准确,适用于含有金属螯合物的金属加工助剂成分的快速鉴定。展开更多
文摘采用溶胶-凝胶法制备了不同稀土金属和过渡金属离子为助催化剂的SiO_2负载型磷钼酸(HPMo)催化剂M-HPMo/SiO_2(M=Eu、La、Ni、Co),研究了此催化剂在模拟柴油的催化氧化脱硫反应中的性能。使用X射线衍射(XRD)、傅里叶变换-红外光谱FT-IR、N2吸附-脱附等分析手段对催化剂的结构进行了表征。结果表明,稀土金属和过渡金属离子的加入保持了磷钼酸的Keggin结构,并促进了磷钼酸活性中心在SiO_2表面的分布,稀土元素催化助剂Eu在反应中的助催化作用最为明显,Eu-HPMo/SiO_2有较高的催化活性。在催化剂用量为0.1 g、反应温度为50℃、n(H_2O_2)/n(S)=3、反应时间60 min,催化剂Eu-HPMo/SiO_2对DBT的脱除率为99.2%。该脱硫反应为表观一级反应,反应表观活化能为51.16±5.79 k J/mol,指前因子A=6154±697。
基金financially supported by Guangdong Innovative and Entrepreneurial Research Team Program ( No. 2013G061)the National Natural Science Foundation of China ( No. 51402055)
文摘This paper reviewed the effect of powder characteristics and additives including metals,rare earth oxides,and ZrO2 on nitridation of Si powder.The decrease of particle size of Si powder increased nitridation.Most of metal additives inhibited nitridation,while some metal additives such as Fe,Cu,Cr,and Ca increased nitrida—tion.Otherwise,the addition of metals might lead to the degradation of physical and mechanical properties of Si3N4.All the rare earth oxides,especially CeO2 and Eu2O3,showed nitridation enhancing effect.In addition,ZrO2 with small particle size showed a stronger enhancing effect.
文摘金属加工助剂是金属加工生产过程中必不可少的化工产品,其组成复杂,易形成螯合物干扰成分分析。该文利用傅立叶变换离子回旋共振质谱(Fourier transform ion cyclotron resonance mass spectrometry,FT-ICR MS)技术的高分辨性能,结合电感耦合等离子体质谱(ICP-MS)、红外光谱(IR)和核磁共振谱(NMR)对一种含未知成分的金属加工助剂进行成分分析。结果表明,该金属加工助剂中含有柠檬酸钠、乙二胺四乙酸(EDTA)与金属铋螯合物。该方法简便、准确,适用于含有金属螯合物的金属加工助剂成分的快速鉴定。
