Promoting Effect of Co, Cu, Cr and Fe on Activity of Ni-Based Alloys in Catalytic Processing of Chlorinated Hydrocarbons.

A series of sponge-like NiM (M = Cu, Co, Cr, Fe; x = 0.00-0.10) alloys was prepared via synthetic routes with subsequent reduction in H atmosphere at 800-1000 °C. Formation of Ni-based solid solutions with face-cantered cubic (fcc) lattice of nickel was proven by X-ray diffraction analysis for all prepared samples. NiM alloys were explored as precursors for self-organizing catalysts active in processing of 1,2-dichloroethane into carbon nanomaterial (CNM). According to kinetic studies of CNM growth performed at 600 °C, the catalytic activity of NiM samples changes as follows: Cr > Co-Cu ≫ Fe. Ni-Cr sample showed rather stable performance during 4 h whereas Ni-Co, Ni-Cu and Ni (reference) samples underwent rapid deactivation after ~150 min of reaction. The presence of the residual amount of Cr (0.5 at.%) found by energy dispersive X-ray microanalysis method in the composition of active Ni particles responsible for the growth of CNM is considered to be a key factor providing the stable catalytic performance. The obtained carbon product is represented by well-ordered segmented fibers (0.4-0.8 μm in diameter) and characterized with comparatively high textural parameters (surface area 290-330 m/g, pore volume 0.43-0.57 cm/g). [ABSTRACT FROM AUTHOR]