Facile fabrication of porous carbon nanofibers encapsulated with nanoscale exposed Ni for producing high-purity hydrogen from cheap glycerol

Tang, Wanlian; Chen, Ziyin; Millán, Marcos; Zuo, Xiaohua; Yuan, Guanming; Cui, Zhengwei; Dong, Zhijun; Cong, Ye; Li, Xuanke

doi:10.1016/j.ijhydene.2023.06.190

Cited by 4 publications

(4 citation statements)

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“…The oxidation status of Ni may come from a small amount of NiO that was not fully reduced and again oxidized Ni from ultrafine Ni nanoparticles (∼10 nm) in fresh reduced catalysts. It can be observed that a relatively high proportion of Ni 0 in both 10 wt % Ni/ACF and 10 wt % Ni/CB compared with that in Ni/Al 2 O 3 , which indicates that porous carbon supports have a certain effect on promoting the reduction of NiO (verified by XRD analysis) and simultaneously preventing the oxidation of Ni nanoparticles . H 2 -TPR curves of different Ni-based catalysts before H 2 reduction are shown in Figure b.…”

Section: Resultsmentioning

confidence: 88%

“…It is evidenced that the dispersion effect of Ni nanoparticles in the two carbon supports is better than that of Al 2 O 3 , in combination with the SEM and TEM analyses, indicating that carbon supports with a large specific surface area and abundant porosity are more conducive to the dispersion of active metals. It is amazing that partial NiO component has been reduced to Ni in the 500 °C-pyrolyzed carbon-supported catalysts before H 2 reduction as shown in Figure d owing to the carbon thermal reduction role on the small amorphous NiO particles (own weak diffraction peaks) . By contrast, there are only NiO diffraction peaks in the unreduced Ni/Al 2 O 3 catalyst.…”

Section: Resultsmentioning

confidence: 97%

“…It is interesting to note that the recyclability of 5 wt % Pt/C is pretty good according to three recycle experiments and the nitrobenzene conversions show a negligible loss of ∼1%. Some new strategies for the preparation of more stable nonprecious metal catalysts such as carbon encapsulation and alloying technology, ,, which can be employed in the following study.…”

Section: Resultsmentioning

confidence: 99%

“…abundant porosity are more conducive to the dispersion of active metals. It is amazing that partial NiO component has been reduced to Ni in the 500 °C-pyrolyzed carbon-supported catalysts before H 2 reduction as shown in Figure4dowing to the carbon thermal reduction role on the small amorphous NiO particles (own weak diffraction peaks) 37. By contrast, there are only NiO diffraction peaks in the unreduced Ni/ Al 2 O 3 catalyst.XPS profiles of the Ni 2p 3/2 core-level spectra of different Ni-based catalysts after H 2 reduction are shown in Figure5a.…”

mentioning

confidence: 95%

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Effects of Support Types and Their Porosity Characteristics on the Catalytic Performance of Ni-Based Catalysts in Nitrobenzene Hydrogenation to Aniline

Jiang,

Yuan,

Cui

et al. 2023

Ind. Eng. Chem. Res.

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Ni-based catalysts are increasingly being used in nitrobenzene hydrogenation. How to select suitable catalyst supports is crucial for upgrading the catalytic performance. Herein, three Ni-based catalysts supported on activated carbon fiber (ACF), mesoporous carbon black (CB), and γ-Al2O3 were tested for nitrobenzene hydrogenation. The influence of catalyst supports, their porosity characteristics, and reaction conditions on the catalytic performance was investigated. The results show that 10 wt % Ni/CB catalyst owns an ultrafine active Ni nanoparticles (∼10 nm) with a uniform dispersion and thus exhibits the optimal catalytic activity. The conversion of nitrobenzene and the selectivity to aniline could reach nearly 100% at 120 °C for 1 h. By contrast, it takes 2 h to achieve the same conversion for 10 wt % Ni/ACF at 120 °C, whereas 10 wt % Ni/Al2O3 needs a severe reaction at 150 °C for 2 h. The turnover frequency of 10 wt % Ni/CB approaches 38 h–1, which is higher than those of other catalysts. Nitrobenzene hydrogenation over different catalysts conforms to a first-order reaction, and the apparent activation energy of 10 wt % Ni/CB (42.6 kJ/mol) is significantly lower than that of 10 wt % Ni/Al2O3 (66.0 kJ/mol). Moreover, 10 wt % Ni/CB catalyst exhibits a good recyclability and structural stability owing to the existence of abundant mesopores in CB, in comparison with 10 wt % Ni/ACF and Ni/Al2O3. It is the mesopores rather than the micropores in carbon supports to postpone the deactivation of Ni-based catalysts. This work demonstrates the superiority of porous carbons as catalyst supports over Al2O3 in nitrobenzene hydrogenation.

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Section: Resultsmentioning

confidence: 88%

Section: Resultsmentioning

confidence: 97%