Preparation and characterization of spherical nickel-doped carbonized resin as hydrogenation catalysts II. Thermal decomposition of resin and preparation of metal-doped catalysts with different nickel loadings

A series of spherical nickel and calcium-doped carbonized resins (Ni-Ca/C), containing Ni metal from 0% to 12% with nearly nionodisperse Ni particles distributed from 9 A to 20 A and having microporous structure with specific surface area from 510 m(2)/g to 650 m(2)/g and high catalytic activity for hydrogenation, were prepared by carbonizing nickel and calcium-doped bead-shaped polymer-D152 Amberlytes (Ni-Ca/D152) having different nickel loadings by exchanging calcium-doped D152 resins (Ca/D152) with Ni2+ of different contents in NH3-NH4+ solution as well as C2H5OH solution. The advantage of exchanging Ca/D152 with Ni(NH3)(2+)(x) (x = 1-6) solution 4 is to make bead-shaped Ni-Ca/C with low nickel loadings, and exchanging with Ni2+ (C2H5OH, H2O) solution is preferable to make bead-shaped Ni-Ca/C with high nickel loadings. To increase the understanding of the pyrolysis mechanism of Ni-Ca/D152, GC, DTA, TGA, XRD and elemental analysis were used to investigate the carbonization process and properties of Ni-Ca/C. Nickel and calcium in D 152 significantly accelerated the carbonization process and the steam activation process of carbonized resin. The thermal decomposition of D 152 mainly occurred between 380 degrees C and 520 degrees C. The reduction of nickel ion to metallic nickel and the formation of CaCO3 from Ca(OH)(2) and CO2 took place in the carbonization process at 500 degrees C and below. (C) 2007 Elsevier Ltd. All rights reserved.