The Effect of Precursor Temperature on the Surface and Interface Structure of Ni/ZSM-5 Hydrogenation Catalyst

A series of Ni/ZSM-5 catalysts with different physical and chemical properties were prepared by immersion-precipitation method by adjusting the temperature of the precursor. The structure and properties of the catalyst were characterized by XRD, TEM, N₂ adsorption-desorption, H₂-TPR, NH₃-TPD and XPS. The influence of precursor temperature on the hydrogenation performance of m-dinitrobenzene was investigated, and the effects of reaction temperature and hydrogen pressure on the reaction were also examined, as well as the stability of the optimal catalyst. The results show that the particle size reduces gradually and the dispersion degree of Ni nanoparticles on ZSM-5 support becomes better as the precursor temperature is increased, which is conducive to improving the catalytic reaction rate. When the precursor temperature was 60 °C, the reaction temperature was 115 °C, the hydrogen pressure was 2.6 MPa, and a mixed solvent of ethanol and deionized water was employed. After 10 min of reaction, both the conversion rate of m-dinitrobenzene and the selectivity of m-phenylenediamine reached 100%. Under the same conditions, the conversion rate of m-dinitrobenzene was 44.73% and the selectivity of m-phenylenediamine was 9.83% after 60 min of reaction for Raney-Ni. The catalyst in this study not only saves solvent costs but also exhibits excellent catalytic performance in tests. After ten cycles of the catalyst, the conversion rate of m-dinitrobenzene was 100%, and the selectivity of m-phenylenediamine was 97.66%.

Graphical Abstract