Effect of support size for stimulating hydrogen production in phenol steam reforming using Ni-embedded TiO2 nanocatalyst
Effect of support size for stimulating hydrogen production in phenol steam reforming using Ni-embedded TiO2 nanocatalyst
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DOI：
10.1016/j.jece.2019.103604
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发表时间：
2020-02-01
影响因子：
7.7
通讯作者：
Khoja, Asif Hussain
中科院分区：
文献类型：
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作者：
Baamran, Khaled Saeed;Tahir, Muhammad;Khoja, Asif Hussain
制备了负载镍的可还原二氧化钛（TiO 2），以最大化金属-载体相互作用来促进苯酚水蒸气重整（PSR）制氢（H-2）。采用溶胶-凝胶辅助浸渍法制备了催化剂，并通过XRD、FE-SEM、EDX、BET、H2-TPR和TEM等手段对催化剂进行了表征。考察了Ni/TiO 2-A（11-49 nm）、Ni/TiO 2-B（22-196 nm）和Ni/TiO 2-C（69-205 nm）三种不同粒径催化剂对传质极限、催化活性和积炭形成的影响。使用更小的粒径的TiO 2实现了具有良好形貌和Ni分散的更高的BET表面积。Ni/TiO 2-A催化剂的苯酚转化率和H2-产率分别为98.3%和76.9%。当在Ni/TiO 2-B和Ni/TiO 2-C样品中使用大尺寸TiO 2颗粒时，分别实现了93.7%和73.1%的苯酚转化率和71.2%和55.6%的H-2产率。这表明较小的载体颗粒尺寸具有较高的转化率和产率，并且当载体尺寸增加到较大的颗粒尺寸时活性下降。这是明显的小颗粒尺寸导致更大的表面积，更高的金属分散和有效的表面反应，最小的内部扩散效应。此外，稳定性分析揭示了在较小的颗粒上连续的H-2生产而没有明显的失活，然而，由于明显的焦炭沉积，使用大载体尺寸的活性随着运行时间的推移而下降。因此，载体尺寸和金属与载体的相互作用对最大化活性和稳定性具有显著贡献，并且可以进一步用于可再生氢生产的重整系统中。
Fabrication of reducible titanium dioxide (TiO2) loaded with nickel (Ni) to maximize metal-support interaction for stimulating hydrogen (H-2) production via phenol steam reforming (PSR) has been investigated. Catalysts, synthesized by sol-gel assisted impregnation method, were characterized by XRD, FE-SEM, EDX, BET, H-2-TPR and TEM techniques. The effects of three different catalyst sizes namely Ni/TiO2-A (11-49 nm), Ni/TiO2-B (22-196 nm) and Ni/TiO2-C (69-205 nm) for their mass transfer limitation, catalytic activity and coke formations were evaluated. Using smaller particle sizes of TiO2 higher BET surface area with good morphology and Ni dispersion was achieved. The Ni/TiO2-A sample shows highest phenol reforming activity with phenol conversion and H-2 yield of 98.3 and 76.9 %, respectively. When large sizes TiO2 particles in Ni/TiO2-B and Ni/TiO2-C samples were employed, phenol conversion of 93.7 and 73.1 % and H-2 yield of 71.2 and 55.6%, respectively, were achieved. This reveals that smaller support particle sizes have higher conversion and yields, and activity was declined when support size was increased to larger particle sizes. This was obviously small particle sizes resulted in larger surface area, higher metal dispersion and efficient surface reactions with minimum internal diffusion effects. Furthermore, stability analysis reveals continuous H-2 production over smaller particles without obvious deactivation, however, activity was declined over time on stream using large support size due to obvious coke depositions. Thus, supports sizes and interaction of metal and support has significant contribution to maximize activity and stability and can be further employed in reforming systems for renewable hydrogen production.