The effect of potassium on CO disproportionation on Ni/Al2O3 catalyst
•Potassium does not promote CO dissociation/disproportionation on Ni/Al2O3 catalysts.•Carbon deposits formed on K/Ni/Al2O3 comprise both C ad-atoms and CO ad-molecules.•C atoms and CO molecules interact with potassium forming K+1–C and K+1–CO complexes adsorbed on nickel.•The interaction of C and CO with potassium is responsible for special properties of K/Ni/Al2O3 catalysts.
The effect of potassium on CO disproportionation on Ni/Al2O3 catalyst was studied. The examinations showed that small potassium content, below 1.5 mol%, does not affect the reaction rate while large potassium content, 6.0 mol%, slightly hinders the reaction. Carbon deposits produced during the disproportionation were studied by TP hydrogenation method. The measurements showed that: (i) the deposit formed on unpromoted sample is easy to hydrogenate and consists of adsorbed carbon atoms while (ii) the deposits formed on potassium promoted samples are difficult to hydrogenate and consist of co-adsorbed C atoms and CO molecules, being in intimate contact with potassium.
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Journal: Applied Catalysis A: General - Volumes 460–461, 10 June 2013, Pages 78–81