Highly selective hydrogenation of halogenated nitroarenes over Pt nanoparticles on DMA-modified graphene

Abstract

The catalytic hydrogenation of aromatic nitro compounds to amines is crucial for synthesizing pharmaceuticals and agrochemicals, yet conventional noble metal catalysts (e.g., Pt and Pd) suffer from undesirable dehalogenation when applied to halogenated nitroarenes. To address this selectivity challenge, we developed platinum nanoparticles supported on 2,5-dimethoxyaniline (DMA)-modified reduced graphene oxide (Pt/DMA-RGO) via a hydrothermal synthesis strategy. Comprehensive characterization confirmed that DMA functionalization promotes the formation of ultra-small Pt nanoparticles (∼5 wt%) with strong Pt–N interactions and optimal electronic modulation, enhancing both metal dispersion and substrate adsorption. Under mild conditions (50 °C and 2 MPa H₂), Pt/DMA-RGO achieves >95% selectivity for halogenated anilines across diverse substrates, without detectable dehalogenation, while maintaining near-quantitative conversions (85–99%). Crucially, it outperforms unmodified Pt/GO and commercial Pt/C in both activity and selectivity, and exhibits exceptional stability over five recycling cycles. This work provides a practical, support-engineered catalyst for sustainable synthesis of high-value halogenated anilines in industrial applications.