Formation of Active Centers of Nickel–Zinc Catalysts Deposited on the Nanodiamond for the Selective Hydrogenation of Phenylacetylene

E. V. Golubina, E. S. Lokteva, A. V. Erokhin, V. Yu Murzin, V. S. Chernikova, A. A. Veligzhanin

Research output: Contribution to journalArticlepeer-review

Abstract

Abstract: A study is performed of bimetallic catalysts NiZn/ND with ratios Ni : Zn = 1 : 1 and 1 : 3 prepared by impregnation using detonation nanodiamond (ND) as a support. They were compared with monometallic Ni/ND and Zn/ND. It is shown by nitrogen adsorption/desorption, scanning and transmission electron microscopy that metal deposition does not affect the porous structure or morphology of a support. Coordination of metal precursors on a nanodiamond surface proceeds with the participation of functional groups, as is confirmed by a change in the electrokinetic charge of the surface. The reduction of metal precursors is studied by temperature-programmed reduction and in situ XAFS spectroscopy. In Ni-containing samples, two forms of Ni2+ are found that are bonded differently with the support. ZnO is not reduced in the samples upon treatment with hydrogen at temperatures up to 400°C. The fraction of reduced nickel is determined by analyzing XANES spectra. Virtually full reduction of nickel is observed in a catalyst with a Ni : Zn ratio of 1 : 1 after 4 h of in situ treatment with hydrogen inside a spectrometer cell at 400°C, but not at a Ni : Zn ratio of 1 : 3 under the same conditions. The highest selectivity of styrene formation in the reaction of phenylacetylene hydrogenation throughout the investigated range of temperatures (100–350°С) is ensured by NiZn/ND; NiZn3/ND is less active and selective, since ZnO closes the active nickel centers and prevents the adsorption of phenylacetylene.
Original languageEnglish (US)
Pages (from-to)492-502
Number of pages11
JournalRussian Journal of Physical Chemistry A
Volume95
Issue number3
DOIs
StatePublished - Apr 5 2021

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