An experimental and first principles DFT investigation on the effect of Cu addition to Ni/Al₂O₃ catalyst for the dry reforming of methane

The influence of varying Cu atomic ratios in a bimetallic Ni-Cu catalytic system for the CO₂ or Dry Reforming of Methane (DRM) is investigated experimentally, in conjunction with ab-initio Density Functional Theory (DFT) and Generalized Power Law Expression (GPLE)-based mathematical modeling approaches. Among the synthesized catalysts, an 8:1 Ni:Cu ratio shows highest activity with stable H₂/CO selectivity compared to its monometallic counterpart. Detailed physico-chemical characterization of the catalysts indicate that copper addition minimizes deactivation by forming a Ni-Cu alloy that increases reducibility of the NiO and limits the tendency of the active site toward coke formation. DFT calculations reveal increased energy barrier for carbon adsorption, whilst promoting facile removal of deposited carbon. GPLE analysis of the deactivation profiles suggest coking as the primary deactivation route in monometallic Ni catalyst; although much lesser in extent, deactivation of Ni₈Cu₁/Al₂O₃ catalyst is induced by both sintering and coking regimes.

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Published in: Applied Catalysis A: General
License: http://creativecommons.org/licenses/by/4.0/
See article on publisher's website: https://dx.doi.org/10.1016/j.apcata.2020.117699