目前草甘膦工业生产母液含大量甲醛,今采用Pt/C催化剂在反应过程中催化氧化甲醛以期提高母液循环套用效率。运用自制Pt/C催化剂研究甲醛和甲酸的氧化反应及其动力学。XRD和TEM测定表明,Pt/C催化剂中Pt的平均粒径为1.4 nm,分散性较好。...目前草甘膦工业生产母液含大量甲醛,今采用Pt/C催化剂在反应过程中催化氧化甲醛以期提高母液循环套用效率。运用自制Pt/C催化剂研究甲醛和甲酸的氧化反应及其动力学。XRD和TEM测定表明,Pt/C催化剂中Pt的平均粒径为1.4 nm,分散性较好。消除内、外扩散影响后在反应压力0.6 MPa、搅拌转速800 r×min^(-1)、氧气流量120 mL×min^(-1)及反应温度323.15~353.15 K的条件下进行甲醛和甲酸氧化反应动力学实验,建立本征动力学模型并运用实验数据进行拟合计算得到动力学参数,甲醛氧化生成甲酸反应活化能为36.04 k J×mol^(-1),甲酸氧化反应活化能为19.93 k J×mol^(-1),甲醛与甲酸的吸附热分别为-60.26 k J×mol^(-1)和-39.96 k J×mol^(-1)。展开更多
Pt/graphite catalyst was prepared by incipient wetness impregnation using H2PtCl6·6H2O as precursor. The catalyst was characterized by SEM, XRD, XPS and its degradation ability for oxalic acid was evaluated. The ...Pt/graphite catalyst was prepared by incipient wetness impregnation using H2PtCl6·6H2O as precursor. The catalyst was characterized by SEM, XRD, XPS and its degradation ability for oxalic acid was evaluated. The preparation parameters, including the reduction temperature, Pt loading and pyrolysis were studied. The optimal preparation conditions were 350 ℃ with Pt loading of 1.0%. Results show that the loading of Pt can significantly enhance catalytic activity of graphite and that Pt/graphite catalytic ozonation can effectively remove oxalic acid in aqueous solution. The BET surface area of graphite is much smaller than that of activated carbon, however, the catalytic activity of Pt/graphite towards oxalic acid degradation is higher than that of Pt/AC. The XPS results indicate that the active phase at catalyst surface is in the form of Pt0. Compared with that of reduction process in hydrogen, the activity of Pt/graphite catalyst decreases when it is prepared by pyrolysis in air due to the lower Pt dispersion on graphite surface.展开更多
文摘目前草甘膦工业生产母液含大量甲醛,今采用Pt/C催化剂在反应过程中催化氧化甲醛以期提高母液循环套用效率。运用自制Pt/C催化剂研究甲醛和甲酸的氧化反应及其动力学。XRD和TEM测定表明,Pt/C催化剂中Pt的平均粒径为1.4 nm,分散性较好。消除内、外扩散影响后在反应压力0.6 MPa、搅拌转速800 r×min^(-1)、氧气流量120 mL×min^(-1)及反应温度323.15~353.15 K的条件下进行甲醛和甲酸氧化反应动力学实验,建立本征动力学模型并运用实验数据进行拟合计算得到动力学参数,甲醛氧化生成甲酸反应活化能为36.04 k J×mol^(-1),甲酸氧化反应活化能为19.93 k J×mol^(-1),甲醛与甲酸的吸附热分别为-60.26 k J×mol^(-1)和-39.96 k J×mol^(-1)。
文摘Pt/graphite catalyst was prepared by incipient wetness impregnation using H2PtCl6·6H2O as precursor. The catalyst was characterized by SEM, XRD, XPS and its degradation ability for oxalic acid was evaluated. The preparation parameters, including the reduction temperature, Pt loading and pyrolysis were studied. The optimal preparation conditions were 350 ℃ with Pt loading of 1.0%. Results show that the loading of Pt can significantly enhance catalytic activity of graphite and that Pt/graphite catalytic ozonation can effectively remove oxalic acid in aqueous solution. The BET surface area of graphite is much smaller than that of activated carbon, however, the catalytic activity of Pt/graphite towards oxalic acid degradation is higher than that of Pt/AC. The XPS results indicate that the active phase at catalyst surface is in the form of Pt0. Compared with that of reduction process in hydrogen, the activity of Pt/graphite catalyst decreases when it is prepared by pyrolysis in air due to the lower Pt dispersion on graphite surface.
