A novel modification method for nickel foam support and synthesis of a metal-supported hierarchical monolithic Ni@Pd catalyst for benzene hydrogenation

A simple novel surface modification method for the nickel foam support was presented. Based on the support, the metal-supported hierarchical monolithic Ni@Pd catalyst was prepared for benzene hydrogenation to cyclohexane in this work. Effects of synthesis conditions on the morphology of hierarchical monolithic Ni were studied. The results show that growth of nickel nanostructures on nickel foam follows epitaxial growth mechanism. Under the mild synthesis conditions, nickel crystal grows along {1 1 1} planes with high surface energy. When reaction temperature and NiCl2 concentration further increase and reaction time prolongs, accelerated growth of {1 0 0} or {1 1 0} planes and Ostwald ripening process play important roles in synthesis of hierarchical monolithic Ni. The monolithic Ni@Pd catalyst was further synthesized by hierarchical monolithic Ni reducing Pd2+ ions. The as-prepared catalysts were characterized by scanning electronic microscopy (SEM), CO chemisorption and X-ray diffraction (XRD) techniques. The experimental results show that monolithic Ni@Pd has the higher catalytic performance than monolithic Ni and the conventional Pd/Ni foam. Improvement of the catalytic activity is attributed to the higher catalytic surface areas and synergetic effects between Pd and Ni.