Mahy Julien G, Delbeuck Thierry, Tran Kim Yên, Heinrichs Benoît, Lambert Stéphanie D
Department of Chemical Engineering-Nanomaterials, Catalysis & Electrochemistry, University of Liège, B6a, Quartier Agora, Allée du six Août 11, 4000 Liège, Belgium.
Institut National de la Recherche Scientifique (INRS), Centre-Eau Terre Environnement, Université du Québec, 490, Rue de la Couronne, Québec, QC G1K 9A9, Canada.
Gels. 2023 Mar 25;9(4):275. doi: 10.3390/gels9040275.
Monometallic catalysts based on Fe, Ni and Pd, as well as bimetallic catalysts based on Fe-Pd and based on Ni-Pd supported on silica, were synthesized using a sol-gel cogelation process. These catalysts were tested in chlorobenzene hydrodechlorination at low conversion to consider a differential reactor. In all samples, the cogelation method allowed very small metallic nanoparticles of 2-3 nm to be dispersed inside the silica matrix. Nevertheless, the presence of some large particles of pure Pd was noted. The catalysts had specific surface areas between 100 and 400 m/g. In view of the catalytic results obtained, the Pd-Ni catalysts are less active than the monometallic Pd catalyst (<6% of conversion) except for catalysts with a low proportion of Ni (9% of conversion) and for reaction temperatures above 240 °C. In this series of catalysts, increasing the Ni content increases the activity but leads to an amplification of the catalyst deactivation phenomenon compared to Pd alone. On the other hand, Pd-Fe catalysts are more active with a double conversion value compared to a Pd monometallic catalyst (13% vs. 6%). The difference in the results obtained for each of the catalysts in the Pd-Fe series could be explained by the greater presence of the Fe-Pd alloy in the catalyst. Fe would have a cooperative effect when associated with Pd. Although Fe is inactive alone for chlorobenzene hydrodechlorination, when Fe is coupled to another metal from the group VIIIb, such as Pd, it allows the phenomenon of Pd poisoning by HCl to be reduced.
采用溶胶-凝胶共凝胶法合成了基于铁、镍和钯的单金属催化剂，以及负载在二氧化硅上的基于铁-钯和镍-钯的双金属催化剂。在低转化率下对这些催化剂进行氯苯加氢脱氯测试，以考虑使用微分反应器。在所有样品中，共凝胶法使2-3纳米的非常小的金属纳米颗粒分散在二氧化硅基质中。然而，注意到存在一些纯钯的大颗粒。这些催化剂的比表面积在100至400平方米/克之间。鉴于所获得的催化结果，除了镍含量低的催化剂（转化率为9%）和反应温度高于240℃的情况外，钯-镍催化剂的活性低于单金属钯催化剂（转化率<6%）。在这一系列催化剂中，增加镍含量会提高活性，但与单独的钯相比，会导致催化剂失活现象加剧。另一方面，钯-铁催化剂的活性更高，与单金属钯催化剂相比，转化率提高了一倍（13%对6%）。钯-铁系列中每种催化剂所获得的结果差异可以用催化剂中更多地存在铁-钯合金来解释。铁与钯结合时会产生协同效应。虽然铁单独对氯苯加氢脱氯无活性，但当铁与VIIIb族的另一种金属（如钯）偶联时，它可以减少钯被HCl中毒的现象。
