Efficient and sustainable transfer hydrogenation and N-formylation of nitroarenes using a facilely synthesized Co₄N/NC nanocatalyst

The efficient and sustainable one-pot transformation of nitroarenes into valorized products is of considerable importance due to its simplicity, cost-effectiveness, and eco-friendliness. Despite its potential, this approach often relies on noble metal catalysts and is hindered by low catalytic activity and the need for elevated temperatures and pressures. Herein, we report a highly efficient nitrogen-doped carbon-encapsulated cobalt nitride nanocatalyst (Co₄N/NC@800), synthesized via a one-pot pyrolysis of a cost-effective precursor for the chemoselective amination and N-formylation of nitroarenes. Formic acid is employed as a biogenic hydrogen donor for the flexible and selective transformation of nitroarenes. Formic acid serves a dual role as both a reducing agent and a formylation reagent, enabling hydrogenation and selective N-formylation of structurally diverse mono- or multi-substituted nitroarenes in a single step. The catalyst offers precise control over the reduction pathway, favoring the formation of aryl amines in methanol, while selectively producing N-formylated products in an ethanol-water (1:4, v/v) system. Optimized reaction parameters, including reaction time, solvents, and additives, contribute to enhanced catalytic performance. Notably, with only 1.42 wt% cobalt loading, Co₄N/NC@800 achieves 99 % nitrobenzene conversion with 98 % selectivity for aniline and N-phenylformamide under transfer hydrogenation conditions. The catalyst also exhibits outstanding recyclability, maintaining its robust performance over multiple cycles. Considering the development of a stable catalyst and its applicability, this study highlights the potential of Co₄N/NC@800 as a sustainable and industrially viable nanocatalyst for the selective transfer hydrogenation of nitroarenes.