An Efficient Co/NC Catalyst for the Hydrogenation of ADN to HMDA: Synergistic Effect of Co0 Content and Dispersion

The Co/NC catalyst for the hydrogenation of adiponitrile (ADN) is of great importance to produce high-value-added hexamethylenediamine (HMDA), which is the raw material for nylon-66. However, current research has not taken the Co particle size distribution effect fully into account for the ADN hydrogenation performance. In this work, Co/NC catalysts with various Co particle sizes using N-doped carbon as the support were prepared to investigate their activity differences. Among all catalysts, the Co/NC catalyst with an average Co particle size of 13.3 nm exhibited the best performance due to its most dispersed Co0 active site, reaching a complete ADN conversion within 40 min with an HMDA selectivity of 83.68%. It displayed a surprising HMDA STY of 49.77 mmol·gcat–1·h–1 under a greatly reduced activation energy (65.30 kJ·mol–1) with a reaction rate constant of 2.98 × 107 min–1. XPS and H2 pulse adsorption characterizations proved that the synergy between the Co0 content and dispersion emerged as the predominant factor governing the catalytic activity. This work provided a promising method for the design of an advanced catalyst for ADN hydrogenation.