Nickel phyllosilicate derived metal–acid bifunctional Ni/SiO2 catalysts for selective reductive amination of alcohols

The reductive amination of alcohols offers a cost-effective and sustainable pathway for the synthesis of amines. However, achieving high selectivity for primary amines remains a challenge. Herein, we report a nickel phyllosilicate catalyst (Ni/SiO₂-AE) synthesized via ammonia evaporation, which demonstrates superior catalytic performance with 53.2% alcohol conversion and 96.2% primary amine selectivity. This outperforms conventional Ni/SiO₂ catalysts prepared by impregnation (16.5% conversion, 98.6% selectivity) and deposition-precipitation (41.3% conversion, 94.5% selectivity). The Ni/SiO₂-AE catalyst exhibits remarkable stability over five reaction cycles, demonstrating both durability and recyclability. Characterization studies reveal that the high catalytic performance stems from the synergy between highly dispersed Ni⁰ nanoparticles and Lewis acid sites derived from unsaturated Ni(II) species, which facilitate alcohol adsorption and activation. Additionally, the robust skeletal structure of nickel phyllosilicate contributes to the recyclability of the Ni/SiO₂-AE catalyst. The metal–acid bifunctional Ni/SiO₂-AE catalyst also displays broad substrate applicability, effectively converting diverse alcohols into their corresponding primary amines.