Sustainable, solvent-free and fast synthesis of highly durable bimetallic Ni-based catalysts for efficient furfural hydrogenation

• Sustainable solvent-free synthesis of stable Ni x Zn@CNT catalyst was developed. • Unique encapsulated Ni 3 ZnC 0.7 active phase within CNT enhances the accessibility of catalytic sites. • Outstanding catalytic activity in furfural hydrogenation was achieved. • The catalyst demonstrated a superior recyclability performance due to encapsulation of active phase. Ni-based catalysts show promise in valorization of bio-based aldehydes. Designing an efficient and stable Ni-based catalysts for bio-conversion still remains a significant challenge. In this work, a sustainable, simple, and solvent-free method was developed to synthesize Ni x Zn@CNT catalyst with unique active phase Ni 3 ZnC 0.7 encapsulated in carbon nanotubes (CNT). The amount of active phase was regulated by varying Ni/Zn doping content. The as-obtained Ni 4 Zn@CNT (Ni/Zn ratio is 4:1) demonstrated excellent catalytic activity for furfural hydrogenation, yielding 99% conversion and 86.75% selectivity to furfuryl alcohol (FAOL). Density functional theory (DFT) calculations, XRD, and Py-FTIR analyses demonstrated that the activation of FAOL and H 2 was synergistically enhanced by the formed Ni 3 ZnC 0.7 phase and Ni 0 . Benefiting from the encapsulation of the active phase uniformly in CNT, Ni 4 /Zn@CNT catalyst displayed outstanding reusability with more than 98% of the furfural conversion even after reuse for six times, thereby outperforming most reported Ni-based catalysts. The method developed in this study provides a sustainable approach for preparing highly durable and efficient Ni-based catalysts for hydrogenation reaction.