An effective method for increasing the activity of nickel boride catalyst nano-particles in hydrogenation reactions: Low-temperature hydrogen treatment

Authors:  Firouzeh Taghavi, Cavus Falamaki, Alimemad Shabanov, Mina Seyyedi, Mehdi Zare

Abstract:
It is shown that low temperature (<100 ^◦C) hydrogen treatment of nano nickel boride catalysts is an efficient process for the enhancement of their activity in the p-nitrophenol (PNP) to p-aminophenol (PAP) hydrogenation reaction. It has been shown that such a process excludes initial borate species present on the surface and within the catalyst nano-particles by promoting their dissolution in the liquid phase. The latter phenomenon is enhanced by increasing the temperature. Treatment in the absence of hydrogen results in no reaction rate enhancement. Instead, the activity falls significantly below that of the as-synthesized catalyst. The effect of hydrogen treatment on the catalyst physical properties was investigated using FTIR, XRD, nitrogen adsorption and FESEM analysis. Mathematical simulation of the PNP hydrogenation reaction rate supports the hypothesis that the rate enhancement is mainly due to the increase of the catalyst specific surface area and partial reduction of surface nickel oxide species. The mechanism by which hydrogen increases the specific surface is discussed.

Keywords:
Nickel boride
Direct hydrogenation
Hydrogen treatment
Catalyst

Published in: Applied catalysis A: General  (Volume 453, Pages 1-402, 26 February 2013)

Publisher: Elsevier

ISSN Information: 0926-860X

An effective method for increasing the activity of nickel boride catalyst nano-particles in hydrogenation reactions: Low-temperature hydrogen treatment

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