Kinetic reaction and deactivation studies on thermocatalytic decomposition of methane by electroless nickel plating catalyst

Abstract

Hydrogen produced by thermocatalytic decomposition of methane is a promising approach to reduce the greenhouse gas effects on environment. A series of experiments were carried out to study the intrinsic kinetic reaction rate, reaction mechanism and catalyst deactivation in methane decomposition using electroless nickel plating on SBA-15 as the catalyst in a fixed bed reactor. The experiments were conducted under atmospheric pressure at a temperature range of 525–600 °C and different methane contact times based on varying methane flow rates over a catalyst bed of fixed weight and depth. The reaction order of kinetic reaction rate was found to be 2. The experimental value of the activation energy for the overall methane decomposition reaction was 113.993 kJ mol−1. A deactivation activity model was used and it showed good agreement with the experimental catalytic activities during the catalyst deactivation reaction for the range of experimental conditions. A deactivation order of 0.5 and an activation energy for the deactivation reaction of 147.870 kJ mol−1 were obtained. Transmission electron microscopy (TEM) was carried out to characterize the deactivated catalysts. TEM micrographs showed that the main deactivation mechanism using electroless nickel plating as catalyst was due to coking which resulted in a loss of active sites.