Journal of Catalysis 251(2007)437-442 Activation of a Au/ Ceo2 catalyst for the Co oxidation reaction y surface oxygen removal/oxygen vacancy formation D. Widmann, R. Leppelt, R.J. Behm 2.0x10 cO 1.0x10 0.0 15x10 10x102 5.0x10 0.0 3.0x10 2.0x10 10x103 0.0 1000 1500 2000 Time /s Fig 1.(a) Sequence of simultaneous CO and O2 pulses dosed on a Au/Ceo2 catalyst pretreated by calcination in 10%0 O2/N2 at 400C(30 min): (b)CO uptake(●. oxygen uptake(▲), and co2 formation(◆) during these pulses
cO b co 0oEoz ▲A▲△▲▲▲▲▲▲▲▲ 50 No. of pulses No of pulses Fig 1.(a) Sequence of simultaneous CO and Oz pulses dosed on a Au/Ceo2 catalyst pretreated by calcination in 10% O2/N2 at 400C(30 min): (b)CO uptake●, oxygen uptake(▲, and CO2 formation(◆) during these pulses. Fg2. CO uptake(●. oxygen uptake(▲), and co2 fomation(◆) during simultaneous CO and O pulses dosed on a Aw Ceo catalyst pretreated by calcination in 10%o O2/N2 at 400C(30 min), subsequent reduction by expo- sure to 100 CO pulses and reoxidation by 50 02 pulses
A MAMAAMAA 20 No. of pulse 4. Conclusion cO In conclusion, we have shown by transient pulse titration measurements in a TAP reactor that a freshly calcined Aw/Ceo2 catalyst becomes significantly more active for CO oxidation on removal of about 7%o of the surface oxygen content. Neither this value nor the steady-state activity of the catalyst in simul 6oz MAAA taneous CO/O2 pulses depends on the procedure followed for surface oxygen removal during reaction (i. e, by reaction with CO in the Co/o reaction gas, by initial reduction with CO and subsequent mild reoxidation, or by controlled reduction). The data clearly demonstrate the role of surface vacancies in activat ing the co oxidation reaction on ceria-supported au catalysts Fig3. CO uptake(·). oxygen uptake(▲, and co2 formation◆) during simultaneous CO and O2 pulses dosed on a Au/CeO2 catalyst pretreated by calcination in 10% O2/N2 at 400"C (30 min)and subsequent reduction by exposure to(a)3 Co pulses, (b)10 CO pulses, and (c)30 Co pulses
第六章过渡金属配合物催化剂及其 相关催化过程 使用过渡金属配合物为催化剂的重要化工过程 过程 反应 典型化刘 反应温度反成压力 /K /10--kPa Wacker Ch+O-“CHCO PKCl2CuCl:(水) 乙酸乙烯酯C2H4+O2+cH:H PoCl. CuCl(水) 6 →CH3(OOCH=CH+H2O 基合成RCH=CH2+CO+t一 HCo(有机溶剂 253.2 CHO RCH, CH: CHO+ RCHCHs R)(PPu):有机和373 15.2 叩牌羰基化CH3OH+CO→→CHc℃XH KHcI》PPh) 嗨剂:CH1有机溶 剂成水溶液 445 5 定向浆合C2H→1(H,) A《CH:)2Cl 373 (Aicgler- Natta) CHt (CaHs). 慧浮于有钒相
第六章 过渡金属配合物催化剂及其 相关催化过程
二、过渡金属配合物中的化学键 1、做催化剂用的有机金属化合 物都含有过渡金属原子或离子, 它们与配位原子、分子键合形 成络合离子或分子。配体围绕 金属原子或离子形成以它们为 Octahedral Tetrahedral 中心的多面体。 c2- Tetragonal pyramidal Trigonal bipyramidal 络合高子或分子的几何构型 Square planar
一、过渡金属配合物中的化学键 1、做催化剂用的有机金属化合 物都含有过渡金属原子或离子， 它们与配位原子、分子键合形 成络合离子或分子。配体围绕 金属原子或离子形成以它们为 中心的多面体