混合物相Co(OH)_(2)/Co_(3)O_(4)催化剂的制备及其费托反应性能研究

Preparation of Catalysts with Mixed Phases Co(OH)_(2)/Co_(3)O_(4) and Their Fischer-Tropsch Synthesis Performance

在还原过程中,非负载型钴基催化剂堆积孔结构容易坍塌,从而使金属钴的比表面积大幅降低,活性中心暴露的数量减少。作者采用简单的水热法制备了Co(OH)_(2)/Co_(3)O_(4)混合物相的非负载型钴纳米颗粒催化剂,用于费托合成反应性能研究。结果表明:相比于单一物相的Co(OH)_(2)或Co_(3)O_(4)催化剂,混合物相的催化剂显示出更高的费托合成反应活性。XRD、TEM、BET、H_(2)-TPR等表征方法揭示出Co(OH)_(2)与Co_(3)O_(4)具有不同的还原性质,两者紧密结合有利于催化剂在还原后维持更大的比表面积,进而有利于更多活性位点暴露,显著提高催化剂的反应活性。

For unsupported cobalt-based catalysts,the pore structures of catalysts are prone to collapse during the reduction process,leading to the significant reduction of the specific surface area of metallic cobalt and the decrease of exposed active sites.In this paper,unsupported cobalt nanoparticle catalysts with different ratios of Co(OH)_(2)and Co_(3)O_(4)crystal phases were prepared using a simple hydrothermal method for Fischer Tropsch synthesis.The results showed that compared to the single phase of Co(OH)_(2)and Co_(3)O_(4),the catalysts with mixed phases presented higher catalytic activity.According to several characterization methods including XRD,TEM,BET,and H_(2)-TPR,it was elucidated that Co(OH)_(2)and Co_(3)O_(4)exhibit different reduction properties.The close combination of the mixed phases favors the formation of a higher surface area after the reduction of catalysts,which leads to the increase of exposed active sites and enhanced catalytic activity.