Effects of Support Types and Their Porosity Characteristics on the Catalytic Performance of Ni-Based Catalysts in Nitrobenzene Hydrogenation to Aniline

作者：Jiang, Hexin; Yuan, Guanming^*; Cui, Zhengwei^*; Zhao, Zhepeng; Dong, Zhijun; Zhang, Jiang; Cong, Ye; Li, Xuanke

来源：Industrial and Engineering Chemistry Research, 2023.

DOI：10.1021/acs.iecr.3c01327

• LIQUID-PHASE HYDROGENATION
• METAL-CATALYSTS
• CARBON
• MICROREACTOR
• NANOCATALYST
• REDUCTION
• CELLULOSE

Ni-based catalysts are increasingly being used in nitrobenzenehydrogenation. How to select suitable catalyst supports is crucialfor upgrading the catalytic performance. Herein, three Ni-based catalystssupported on activated carbon fiber (ACF), mesoporous carbon black(CB), and & gamma;-Al2O3 were tested for nitrobenzenehydrogenation. The influence of catalyst supports, their porositycharacteristics, and reaction conditions on the catalytic performancewas investigated. The results show that 10 wt % Ni/CB catalyst ownsan ultrafine active Ni nanoparticles (& SIM;10 nm) with a uniformdispersion and thus exhibits the optimal catalytic activity. The conversionof nitrobenzene and the selectivity to aniline could reach nearly100% at 120 & DEG;C for 1 h. By contrast, it takes 2 h to achievethe same conversion for 10 wt % Ni/ACF at 120 & DEG;C, whereas 10wt % Ni/Al2O3 needs a severe reaction at 150 & DEG;C for 2 h. The turnover frequency of 10 wt % Ni/CB approaches38 h(-1), which is higher than those of other catalysts.Nitrobenzene hydrogenation over different catalysts conforms to afirst-order reaction, and the apparent activation energy of 10 wt% Ni/CB (42.6 kJ/mol) is significantly lower than that of 10 wt %Ni/Al2O3 (66.0 kJ/mol). Moreover, 10 wt % Ni/CBcatalyst exhibits a good recyclability and structural stability owingto the existence of abundant mesopores in CB, in comparison with 10wt % Ni/ACF and Ni/Al2O3. It is the mesoporesrather than the micropores in carbon supports to postpone the deactivationof Ni-based catalysts. This work demonstrates the superiority of porouscarbons as catalyst supports over Al2O3 in nitrobenzenehydrogenation.