that more in situ hydrogen is produced the in situ hydrogen can facilitate c u2014 c scission and saturate c u2550 c in addition radicals such hydroxyl radicals and alkyl radicals are also typically produced free radicals can improve the process of c u2014 c scission thus long hydrocarbon chains of heavy oil become shorter paraffin contents in light fractions collected in storage 20 increase multiple ring aromatics are partially transformed into single or double ring aromatics nitrogen and sulfur contents are also reduced the catalysts may be a transition metals located on catalyst supports b metal oxides and c alkaline earth metal oxides or mixtures thereof and may be doped with transition metals to give transition metal doped catalysts the metal oxides are at least one or combination of tio 2 al 2 o 3 zno zro 2 wo 3 fe 2 o 3 fe 3 o 4 or moo 3 the alkaline earth metal oxides include mgo cao bao the transition metals may be supported on materials such as aluminum silicates clays zeolites and hydroxylapatite the transition metal may belong to groups viib viii ib such as mn re fe co ni ru pd pt cu for example the products include non condensable gases hydrocarbon liquid products and heavy residues consisting of catalysts the non condensable gaseous products are mainly composed of co co 2 light hydrocarbons lt c5 the gaseous product is a by product and can be treated as a flue gas hydrocarbon.