AuCo Nanoparticles Inserted between the Layers of Ti3C2: An Efficient Nanozyme for Aliphatic Nitro-to-Amine Reduction

The construction of nanozyme with superior catalytic activity and stable structure is urgently needed in practical application. Herein, AuCo nanoparticles inserted between the layers of Ti₃C₂ (AuCo/Ti₃C₂) are prepared by strong electrostatic adsorption method and thermal treatment process. The nitroreductase-like activity of AuCo/Ti₃C₂ is explored with a new hydrogenation reaction of 3-nitropropionic acid (3-NPA) to beta-alanine (BA) as probe. AuCo/Ti₃C₂ shows the highest catalytic activity with TOF value of 4.5 × 10¹⁹ molecules·g⁻¹·s⁻¹ in comparison to Au/Ti₃C₂ and Co/Ti₃C₂, attributing to the synergistic effect of Au and Co. In addition, AuCo/Ti₃C₂ also has excellent stability, and the conversion rate of 3-NPA still can maintain 100% at the fifth cycle, which is due to the insertion of AuCo nanoparticles between the layers of Ti₃C₂, and the insertion prevents the aggregation and the detachment of nanoparticles during repeated uses. The above results demonstrate the feasibility of AuCo/Ti₃C₂ in practical application. The plausible mechanism of 3-NPA hydrogenation into BA by NaBH₄ in the presence of AuCo/Ti₃C₂ is proposed. This research provides a promising strategy to enhance the stability of nanozyme, and may open up a new approach in reducing aliphatic nitro to amine.