Pt/AlO coated with N-doped carbon as a highly selective and stable catalyst for catalytic hydrogenation of -chloronitrobenzene to -chloroaniline.

Selective catalytic hydrogenation of -chloronitrobenzene on Pt-based catalysts is a green and high-efficient way for -chloroaniline production. However, supported monometallic Pt catalysts often exhibit undesirable -chloroaniline selectivity. We herein reported supported Pt catalysts with N-doped carbon (NC) as an overcoating (Pt/AlO@NC) to overcome the disadvantage. Three Pt/AlO@NC catalysts with different NC coating amounts were prepared by carbonization of an ionic liquid. For comparison, AlO coated by NC and Pt/AlO coated by SiO were also prepared. A combination characterization confirmed that the NC overcoating was successfully formed on Pt/AlO surface and Pt particles were completely coated by NC layers when ion liquid amount increased to 25 μl per g catalyst. Due to the intimate contact of NC layers and Pt particles Pt-NC heterojunctions were effectively formed on the catalyst surface. For the catalytic hydrogenation of -chloronitrobenzene, Pt/AlO@NC with 25 μl ionic liquid as the NC precursor exhibited 100% selectivity to -chloroaniline at 100% conversion of -chloronitrobenzene. A lower ionic liquid amount led to decreased selectivity to -chloroaniline. Furthermore, no deactivation was observed on Pt/AlO@NC during 5 catalytic cycles. The findings in the study demonstrate that coating noble metal catalysts by N-doped carbon is a promising method to enhance the selectivity and stability for catalytic hydrogenation of -chloronitrobenzene.