Optimization of the potassium promotion of the Co|α-Al2O3 catalyst for the effective hydrogen production via ethanol steam reforming

Abstract

A series of K-Co|α-Al2O3 catalysts doped with potassium in the range of 0–4 wt% were synthesized and studied in the ethanol steam reforming process. The enhancement of activity and selectivity of the Co|α-Al2O3 catalyst upon the K doping was explained by potassium impact on the reducibility of the cobalt oxide precursor and acidity of the catalyst: K promotor inhibited the cobalt reduction and substantially increased the number of strong Lewis sites. The investigations of the surface state of potassium using a species resolved thermal alkali desorption method allowed for defining optimal potassium dispersion accurately, corresponding to the concentration of 0.3 wt%. Samples with higher potassium contents due to the overloading did not exhibit any improvement of the catalyst efficiency. Presented studies revealed the key importance of the precise optimization of the K loading and dispersion on the Co|α-Al2O3 catalyst for efficient hydrogen production via the ethanol steam reforming process.