Plasma-assisted reduction of NiO/Al$_{2}$O$_{3}$ catalyst in atmospheric dielectric barrier discharge

The activation of a NiO/Al$_{2}$O$_{3}$ catalyst has been carried out using a CH$_{4}$ plasma in an atmospheric dielectric barrier discharge reactor. The catalyst was reduced from NiO to the active Ni form, which showed high selectivity for the conversion of CH$_{4}$ into H$_{2}$ and solid carbon. Characterisation of the reduced catalyst by SEM analysis revealed the presence of significant amounts of carbon nanofibres on the catalyst surface. The machanism for the NiO/Al$_{2}$O$_{3}$ catalyst reduction in non-thermal plasma was proposed. In addition, the reduced Ni/Al$_{2}$O$_{3}$ catalyst has been tested for dry reforming of CH$_{4}$. The presence of the catalyst in the discharge greatly decreased the breakdown voltage due to the distortion effect of local electric field around pellets. The plasma reduced catalyst significantly improved the H$_{2}$ selectivity (45.2 {\%}), in comparison to the reaction with no catalyst, resulting in an increase in the H$_{2}$/CO ratio from 0.84 to 2.53.