铜对γ-Al_2O_3负载铁基费-托合成催化剂还原性能的影响

Effects of Copper on the Reducibility of γ-Al_(2)O_(3) Supported Iron Fischer-Tropsch Catalysts

采用X 射线衍射、氢气程序升温还原、氢气程序升温脱附和氧滴定等技术对浸渍法制备的γ Al2O3负载铜/铁费 托合成催化剂进行了表征.结果表明铁以无定型状态处于催化剂载体表面;铁和γ Al2O3载体之间的相互作用使铁氧化物的还原变得困难,还原度较低.少量铜促进了Fe2O3向Fe3O4的还原,降低了该还原过程的起始温度,增大了铁的还原度,增加了催化剂对氢气的化学吸附.但随着铜含量增大,铜铁之间的相互作用逐渐增强,反而抑制了铁氧化物的还原和催化剂对氢气的化学吸附.

The γ-Al_(2)O_(3) supported iron Fischer\|Tropsch catalysts with different copper loading were prepared using incipient wetness impregnation. the reduction, hydrogen desorption, dispersion and crystalline size of the catalysts were studied by X-ray diffraction (XRD), hydrogen temperature-programmed reduction (H_(2)-TPR), hydrogen temperature-programmed desorption (H_(2)-TPD) and oxygen titration (respectively.) It is shown that the metal-support interaction between iron and γ-Al_(2)O_(3) support affects the (reducibility) of iron oxide, and complete reduction is difficult. A small amount of copper can promote the reduction of Fe_(2)O_(3) to Fe_(3)O_(4). However, intimate interaction occurs between the iron and copper with the (increasing) of copper loading, which causes the reduction of iron oxide more difficult. the metal-metal interaction between iron and copper influences the hydrogen-chemisorption properties of metallic iron.