Structure sensitivity reaction of chloroform hydrodechlorination to light olefins using Pd catalysts supported on carbon nanotubes and carbon nanofibers

[Display omitted] •PdCl2 precursor (PdCl) enhances electron-donation to Pd nanoparticles (NPs).•Carbon nanotubes (CNT) promote smaller Pd NPs and charge transfer to Pd NPs.•Small Pd NPs with high electron density favor selectivity to olefins and stability.•PdCl/CNT gives more than 80 % selectivity to olefins with H2/chloroform = 10.•Carbon nanofibers and Pd(NO3)2 favor bigger Pd NPs accelerating deactivation. The upgrading of wasted chloroform in hydrodechlorination for the production of olefins such as ethylene and propylene is studied by employing four catalysts (PdCl/CNT, PdCl/CNF, PdN/CNT, and PdN/CNF) prepared by different precursors (PdCl2 and Pd(NO3)2) supported on carbon nanotubes (CNT) or carbon nanofibers (CNF). TEM and EXAFS-XANES results confirm that Pd nanoparticle size increases in the order: PdCl/CNT