Enhanced synergy between Cu0 and Cu+ on nickel doped copper catalyst for gaseous acetic acid hydrogenation

As the substitution of common noble catalysts in the hydrogenation of carboxylic acid, a highly effective Cu-Ni/SiO2 catalyst was prepared by a novel stepwise ammonia evaporation method. Its performance in the gasphase hydrogenation of acetic acid was further examined. With the introduction of Ni dopant, more stable Cu delta+ sites, which can adsorb more acetic acid, were formed due to the electron transfer from Cu to Ni. This makes more Cu-0 sites available for hydrogen adsorption, which was suggested as the rate-determining step in acetic acid hydrogenation. A conversion of 99.6% was successfully achieved on this new Cu/SiO2-0.5Ni catalyst, accompanied by the ethanol selectivity of 90%. The incorporation of nickel between copper nanoparticles enhances the synergistic effect between Cu-0 and Cu+. It also helps mitigate the aggregation of copper nanoparticles due to the Ostwald ripening effect induced by acetic acid and enhance the stability of copper catalyst in the conversion of carboxylic acid.

Automated summary

The Cu-Ni/SiO2 catalyst prepared by stepwise ammonia evaporation method has shown promising performance in the gas-phase hydrogenation of acetic acid, achieving a high conversion rate of 99.6% and selectivity of 90% towards ethanol. The incorporation of nickel enhances the synergistic effect between Cu-0 and Cu+, improving the stability of the copper catalyst and mitigating aggregation of copper nanoparticles during carboxylic acid conversion.