Understanding the roles of stabilizers and reductants in soluble Pt nanoparticle catalysts for highly efficient hydrogenation of benzoic acid under mild conditions†

Stabilizers and reductants of soluble metal nanoparticle (SMNP) catalysts have particular properties that differ from those of heterogeneous catalysts and can dramatically influence the activity of catalysts. To achieve better performances of SMNP catalysts, the functions of stabilizers and reductants have to be understood. Herein, we prepared a batch of SMNP catalysts by adjusting the amount of stabilizers and the type of reductants and found that the stabilizers and reductants will affect not only the size of catalysts but also the electronic states and accessibility of active metal sites, which determine the activity of catalysts. The SMNP catalyst prepared with a suitable stabilizer and reductant presents significantly higher catalytic activity with complete conversion in the selective hydrogenation of benzoic acid to cyclohexane carboxylic acid under mild conditions (30 °C and 1 atm H₂) than that of the conventional heterogeneous catalyst (Pt/C). Besides, one-step selective hydrogenation of various benzoic acid derivatives was carried out over the SMNP catalyst. These conclusions on the functions of stabilizers and reductants provide new insight into the preparation of high-efficiency SMNP catalysts.