Effect of promoters on the structures and properties of the RuB/γ-Al2O3 catalyst

Effect of promoters (Co, Fe, Sn, Zn) on structures, properties and catalytic performance of RuB/γ-Al2O3 catalyst was studied using in situ XRD, TEM, H2-TPD, XPS and liquid-phase hydrogenation of ethyl lactate to 1,2-propanediol (PDO). It was found that incorporation of Sn or Fe improved the dispersion and thermal stability of RuB. The electron density of Ru and the strength and capacity of H2 adsorption on the RuB catalyst were also enhanced by the incorporation of Sn or Fe. The incorporation of Co or Zn led to a significant decrease in H2 adsorption capacity of the RuB catalyst. Both ethyl lactate conversion and selectivity to 1,2-PDO increased with the incorporation of Sn or Fe. The ethyl lactate conversion decreased sharply with the incorporation of Zn or Co accompanied by an increase in selectivity to 1,2-PDO and lactic acid. The effect of promoters on reaction behavior was discussed on the basis of the characterizations.