A highly dispersed and stable Ni/mSiO2-AE nanocatalyst for benzoic acid hydrogenation

Abstract

A Ni/mSiO₂-AE nanocatalyst was successfully prepared via loading the active nickel species on mSiO₂ by an ammonia evaporation (AE) method. It exhibited excellent catalytic performance in the selective hydrogenation of benzoic acid with the conversion of benzoic acid and selectivity to cyclohexane carboxylic acid being 98.9% and 99.1%, respectively. Furthermore, the catalyst can be recycled four times without appreciable loss of its initial activity. As demonstrated by TEM, the active nickel species was highly dispersed with an average particle size of 3.2 nm in this nanocatalyst, which is much smaller than that of Ni/mSiO₂-IMP (∼18 nm), prepared by a conventional impregnation method. TPR and XPS results revealed the existence of a stronger interaction between the active nickel species and the mSiO₂ support in Ni/mSiO₂-AE, compared to Ni/mSiO₂-IMP. This strong metal–support interaction in Ni/mSiO₂-AE can effectively suppress the loss of the active nickel species during the reaction, resulting in its good stability under relatively harsh reaction conditions.