The performance of Pd, Pt, Rh and Ru based catalysts in the hydrodechlorination of chloromethanes to obtain ethane and ethylene was evaluated by means of computational analysis and hydrodechlorination experiments. A computational analysis using density functional theory (DFT) was developed to obtain preliminary insight on the potential catalytic mechanisms for the reactions involved using palladium, platinum, rhodium and ruthenium metallic clusters. Stable catalytic intermediates were obtained by quantum-chemical calculations in the hydrodechlorination of dichloromethane on Pd-6 and Rh-6 clusters, presenting center dot center dot CH2 and center dot CH3 radicals and C2H4, C2H6 and CH4 products. On the contrary, it was not possible to obtain all these stable intermediates using Pt-6 and Ru-6 clusters. Theoretical analysis revealed lower desorption energies for ethane and ethylene products in Pd-6 than in Rh-6 clusters, what indicates a favorable selectivity of Pd-based catalyst for desired C-2 products. Then, carbon supported catalysts containing these four metals were prepared and experimentally evaluated in the hydrodechlorination of dichloromethane (DCM) and trichloromethane (TCM) at low H-2 excess and a reaction temperature range of 150-400 degrees C. In agreement with computational results, in experimental tests, the Pd based catalyst showed the best performance for the hydrodechlorination of chloromethanes to obtain C-2 products, followed by Rh, Ru and Pt have a poor performance, in special Pt based catalyst, which shows almost no selectivity to C-2 products. This computational and experimental study emphasizes, for the first time, the good performance (high activity and selectivity) of Pd carbon supported catalysts in the valorization of chloromethane compounds to obtain C-2 hydrocarbon products.