Doped Ni thin layer catalysts for catalytic decomposition of natural gas to produce hydrogen

Doped Ni-based Thin Layer Catalysts (Ni-TLCs) for Catalytic Decomposition of Natural Gas (CDNG) were investigated using a new Multilayer Catalytic Reactor (MCR). The influence of K, La, Mg and Cl on activity-stability patterns of a Ni-TLC catalyst was evaluated. An inverse straight-line relationship between carbon capacity (C/Ni, number of CH4 molecules decomposed for Ni atom until complete deactivation) and reaction temperature was found independently of the dopant used. However, dopants significantly affect Ni specific activity (TOF, s1), acting as either an electronic promoter or inhibiting Ni sintering phenomena. Reaction temperature is a key parameter in determining the evolution of coke. At low reaction temperature (<823 K), carbon whiskers form prevalently on ''bare'' and Mg, La, and Cl doped samples, whereas only the encapsulating carbon type formed on a K doped system. High hydrogen productivity was obtained on an Mg doped catalyst which, furthermore, proved to be the most stable system.