A selenium and actived carbon (AC) catalyst has been applied for the selective reduction of nitroarenes to their corresponding amines respectively using sodium borohydride (NaBH4) as a reducing source under mild conditions. Under the optimized conditions, efficient and selective reduction of nitroarenes into the corresponding aromatic amines occurred over a recyclable selenium catalyst. The catalyst can be easily recovered after catalytic reaction and readily reused for 4 cycles with consistent activity hence reduces the cost of the catalyst.

The reduction of aromatic nitro compounds to corresponding azoxy compounds with sodium borohydride was catalyzed by BiO(OH)/actived carbon (AC), which was prepared by equivalent-volume impregnation. The influences of catalyst, sodium borohydride and sodium hydroxide amount were investigated with 10 mmol of nitrobenzene as substrate in methanol at room temperature. The suitable reaction conditions are as follows: 0.2 g of catalyst, 10 mmol of sodium borohydride and 0.1 g of sodium hydroxide. Under the conditions, the seven aromatic nitro compounds were reduced to corresponding azoxy compounds with 27%-90% yields. Moreover, slight deactivation was observed after nine cycles of the catalyst.

Iron oxyhydroxide was prepared by dropping ammonia water to Fe(NO3)3.9H2O dispersed in polyethylene glycol (PEG) 1000. The catalyst was characterized by X-ray powder diffraction, Fourier transform infrared spectroscopy and laser particle size analyzer. The results showed the catalyst modified with polyethylene glycol was amorphous. The addition of PEG during the preparation make the particle size of the catalyst was smaller and more uniform. The catalytic performance was tested in the reduction of nitroarenes to corresponding amines with hydrazine hydrate, and the catalyst showed excellent activity and stability.

Nitrogen doped (N-doped) carbon materials (NCMs) are generally used as electrode materials, and seldom used as catalysts in chemical reaction. In this work, NCMs were prepared by high-temperature pyrolysis using monosodium glutamate as sources of both carbon and nitrogen, magnesium acetate as a porogen, and nickel hydroxide as a graphitization catalyst. The catalytic performance of NCMs was investigated in the reduction of 4-nitrophenol (4-NP) with potassium borohydride at 30 ºC. As metalfree catalysts, all of the NCMs can catalyze the reaction. The graphitization degree and N-doped amount of NCM have a great influence on the catalytic activity. The NCM annealed at 800 ºC has higher activity and stability. The reaction rate constant can reach 0.57 min -1 , and the activation energy was about 36.4 kJ/mol.