Optics and Photonics Society of Iran

The gaseous hydrocarbons dissociation is carried out using the laser induced plasma in the attendance of metal catalysts. Here, both catalytic and plasma known as the competitive mechanisms are applied. In plasma mechanism, the required energy for the dissociation of hydrocarbonic bonds is supplied by the electron impacts. In catalytic mechanism which is based on the adsorption of hydrocarbons molecules on the nano-particles in the plasma plume, the nano-particles splash into the plasma plume due to the laser beam incidence on metal catalysts. The more ablation leads to higher generation rate of species corresponding to higher dissociation rate. Therefore, the ablation depth measurement on the metal catalysts accounts as an indicative parameter for determining the activity of the catalyst. The measurement of ablation depth is performed by Dektak stylus profilometer. In this work, the ablation mass of palladium, iron, nickel and copper targets in laser induced plasma in propane gas and air environment are compared together. The results of the ablation depth analysis exhibit good agreement with the gas chromatography results, such that the higher ablations mass is attributed to greater propane conversion rate. The results show that the palladium demonstrates the highest ablation mass respect to the others.