Schiff Base-Mediated Dual Active Site Catalyst for Efficient N-Formylation of Amines with CO2

Abstract

Using CO₂ as the C1 source for N-formylation of amine is a crucial energy-storage pathway to address the greenhouse effect while generating high-value-added chemicals but is limited by the activation of inert molecules. Herein, a dual active site catalyst with high CO₂ activation and dihydrogen dissociation capacity was fabricated by incorporating a Schiff base and Au nanoparticles (NPs) on silicon dioxide (SiO₂). The modification of the Schiff base not only provides an alkaline environment for CO₂ absorption but also stabilizes Au NPs in a small and highly dispersed state, which regulates the electronic density of the metal for excellent H₂ cleavage. The Schiff base-mediated Au catalyst significantly increased the yield of N-formylmorpholine from 3.9% in unmodified Au/SiO₂ to 83.3% without the addition of any other additives. This work provides a new avenue for designing multisite catalysts by supporting surface modification to achieve simultaneous activation of multiple target substrates for synergistic catalysis.