Catalysts prepared from copper–nickel ferrites for the steam reforming of methanol
Catalysts prepared from copper–nickel ferrites for the steam reforming of methanol
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DOI：
10.1016/j.jpowsour.2015.01.168
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发表时间：
2015-05
影响因子：
9.2
通讯作者：
Yung-Han Huang;Sea-Fue Wang;A. Tsai;S. Kameoka
中科院分区：
文献类型：
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作者：
Yung-Han Huang;Sea-Fue Wang;A. Tsai;S. Kameoka
本研究通过还原Cu-Ni(Ni1−xCuxFe2O4)铁氧体制备了Fe3O4负载的铜和镍催化剂。用固相反应法合成的铜镍铁氧体在H_2气氛中，在240℃到500℃的温度下还原。所有铁氧体在还原前都具有颗粒状形貌和光滑的颗粒表面的特征。对于CuFe2O4、Ni0.5Cu0.5Fe2O4和NiFe2O4铁氧体，分别在240、300和400℃还原时，纳米级的铜和/或镍颗粒(5~32 nm)和中孔(5~30 nm)分布并附着在Fe3O4载体表面。将NiFe2O4铁氧体的还原温度提高到500℃后，Ni颗粒和介孔从Fe3O4表面消失，这是由于在Fe3O4表面形成了Fe-Ni合金覆盖层。在240℃下还原后的CuFe2O4铁氧体在360℃下的产氢速率最高，为149umlSTP/min·g-CAT。铜镍铁氧体中Ni含量的存在促进了逆水煤气变换反应，提高了CO选择性，同时降低了CO2选择性。Fe-Ni合金的形成夸大了这一趋势，并毒化了H_2的生成速度。
In this study, Fe3O4-supported Cu and Ni catalysts are prepared through reduction of Cu–Ni (Ni1−xCuxFe2O4) ferrites. The Cu–Ni ferrites, synthesized using a solid–state reaction method, are reduced at temperatures from 240 °C to 500 °C in a H2atmosphere. All ferrites are characterized with granular morphology and a smooth particle surface before reduction. For the CuFe2O4, Ni0.5Cu0.5Fe2O4and NiFe2O4ferrites reduced at 240, 300, and 400 °C, respectively, nanosized Cu and/or Ni particles (5–32 nm) and mesopores (5–30 nm) are distributed and adhered on the surfaces of Fe3O4supports. After increasing the reduction temperature of NiFe2O4ferrite to 500 °C, the Ni particles and mesopores disappear from the Fe3O4surfaces, which is due to the formation of a Fe–Ni alloy covering on the Fe3O4surfaces. The CuFe2O4ferrite after H2reduction at 240 °C exhibits the highest H2production rate of 149 ml STP/min g-cat at 360 °C. The existence of Ni content in the Cu–Ni ferrites enhances the reverse water gas shift reaction, and raises the CO selectivity while reducing the CO2selectivity. Formation of a Fe–Ni alloy exaggerates the trend and poisons the H2production rate.