Active phase of Ni2P/SiO2 in hydroprocessing reactions

Oyama, S. Ted; Wang, X.; Lee, Yong‐Kul; Chun, Wang‐Jae

doi:10.1016/s0021-9517(03)00017-4

Cited by 230 publications

(152 citation statements)

References 12 publications

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“…This indicates that more hydrogen species adsorbed on Ni 2 P crystallites after reaction, which was perhaps related to P loss. P loss also was found on silica-supported nickel phosphide during HDS [66]. In addition, there was a shift of TPD peak due to spilt-over hydrogen species to higher temperature for the used catalyst (Fig.…”

Section: Catalyst Activitymentioning

confidence: 63%

Gas-phase Hydrodechlorination of Chlorobenzene Over Silica-supported Ni2P Catalysts Prepared Under Different Reduction Conditions

et al. 2007

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The influence of reduction conditions on the properties and reactivity of silica-supported nickel phosphide (Ni 2 P/SiO 2 ) catalysts for gas-phase hydrodechlorination (HDC) of chlorobenzene was investigated. The catalysts prepared under different reduction conditions had the similar specific surface area (*370 m 2 g -1 ), and pore diameter (*5.2 nm) and Ni 2 P crystallites size (10-13 nm). However, comparing with Ni 2 P/SiO 2 catalyst prepared at 923 K with the H 2 space velocity of 15,000 mL g -1 h -1 for 2 h, with increasing the H 2 space velocity from 15,000 to 19,200 mL g -1 h -1 , or the reduction temperature from 923 to 1023 K or the reduction time from 2 to 6 h, the Ni/P ratio in the prepared catalyst was increased from 1/0.56 to about 1/0.50, and the HDC reaction induction period over the catalyst was also shortened from above 30 to 2-4 h. It is suggested that the induction period might be due to the blocking of active sites by excess phosphorus, which results in hindering the activation of chlorobenzene and the adsorption of hydrogen species on Ni 2 P. Under the conditions of 573 K and W Ni /F Cl = 186.6 g Ni mol À1Cl min, the chlorobenzene conversion over the Ni 2 P/SiO 2 catalyst reached 99%, and it did not change during 36 h. The good activity and stability of the Ni 2 P/SiO 2 catalyst was ascribed to the weak interaction between chlorine and Ni 2 P and a great of spilt-over hydrogen species on the catalyst surface.

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Section: Catalyst Activitymentioning

confidence: 63%

Gas-phase Hydrodechlorination of Chlorobenzene Over Silica-supported Ni2P Catalysts Prepared Under Different Reduction Conditions

et al. 2007

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“…There are also more oscillation peaks at the Ni K-edge than at the Fe K-edge, which indicates that more Ni-S is formed than Fe-S. Many studies [98,99,100] have shown that the active phase is a phosphosulfide. It has been found that small amounts of Co in Ni x Co y P catalysts are promoters [33], and it should be interesting to probe the reactivity of small amounts (< 15 mol%) of Fe in NiFeP catalysts.…”

Section: Density Functional Theory Calculationsmentioning

confidence: 99%

Nature of active sites in Ni2P hydrotreating catalysts as probed by iron substitution

Zhao

Oyama

Freund

et al. 2015

Applied Catalysis B: Environmental

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A series of NiFeP/SiO 2 catalysts with different Ni:Fe molar ratios (1:0, 3:1, 1:1, 1:3, 0:1) was investigated for the hydrodesulfurization (HDS) of 4,6-dimethyldibenzothiophene.The Fe component is a good probe for active sites because Ni 2 P and Fe 2 P adopt the same hexagonal crystal structure, yet Fe 2 P is completely inactive for HDS. X-ray diffraction analysis and FTIR spectroscopy of adsorbed CO indicated the formation homologous alloys. At 3.1 MPa and 613 K (340 o C) the activity of the alloys was similar to that of Ni 2 P, which was very high. There was also unprecedented selectivity towards direct desulfurization (DDS). A reconstruction of the NiFe phase occurred to expose more Ni sites, likely driven by the formation of surface Ni-S bonds as observed by EXAFS. The analysis showed that Ni(2) pyramidal sites responsible for hydrogenation were largely replaced by Fe. This left behind Ni(1) tetrahedral sites which favor DDS and explains the reactivity results.

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“…The selectivity to 1,2-PDO remained around 85%, and changed very slightly with conversion of glycerol up to 95.7%. It was reported that transition-metal phosphides such as Ni12P5 and Ni2P can be formed on high temperature treatment under the reducing atmosphere of hydrogen [18,19]. In addition, Huang et al, reported that the formation of the Ni2P alloy phase could improve the selectivity to 1,2-PDO in the glycerol hydrogenolysis over P-doped Ni/SiO2 catalyst [15].…”

Section: Influence Of P Doping On the Catalytic Performancementioning

confidence: 99%

Effect of Phosphine Doping and the Surface Metal State of Ni on the Catalytic Performance of Ni/Al2O3 Catalyst

Cheng

Liang

et al. 2015

Catalysts

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Ni-based catalysts as replacement for noble metal catalysts are of particular interest in the catalytic conversion of biomass due to their cheap and satisfactory catalytic activity. The Ni/SiO2 catalyst has been studied for the hydrogenolysis of glycerol, and doping with phosphorus (P) found to improve the catalytic performance significantly because of the formation of Ni2P alloys. However, in the present work we disclose a different catalytic phenomenon for the P-doped Ni/Al2O3 catalyst. We found that doping with P has a significant effect on the state of the active Ni species, and thus improves the selectivity to 1,2-propanediol (1,2-PDO) significantly in the hydrogenolysis of glycerol, although Ni-P alloys were not observed in our catalytic system. The structure and selectivity correlations were determined from the experimental data, combining the results of X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), hydrogen temperature-programmed reduction (H2-TPR) and ammonia temperature-programmed desorption (NH3-TPD). The presence of NiO species, formed from P-doped Ni/Al2O3 catalyst, was shown to benefit the formation of 1,2-PDO. This was supported by the results of the Ni/Al2O3 catalyst containing NiO species with incomplete reduction. Furthermore, the OPEN ACCESSCatalysts 2015, 5 760 role the NiO species played in the reaction and the potential reaction mechanism over the P-doped Ni/Al2O3 catalyst is discussed. The new findings in the present work open a new vision for Ni catalysis and will benefit researchers in designing Ni-based catalysts.

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Active phase of Ni2P/SiO2 in hydroprocessing reactions

Cited by 230 publications

References 12 publications

Gas-phase Hydrodechlorination of Chlorobenzene Over Silica-supported Ni2P Catalysts Prepared Under Different Reduction Conditions

Gas-phase Hydrodechlorination of Chlorobenzene Over Silica-supported Ni2P Catalysts Prepared Under Different Reduction Conditions

Nature of active sites in Ni2P hydrotreating catalysts as probed by iron substitution

Effect of Phosphine Doping and the Surface Metal State of Ni on the Catalytic Performance of Ni/Al2O3 Catalyst

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