▎ 摘　　要

NOVELTY - Treating (P1) polymeric materials e.g. polyolefinic comprises: (a) submitting the polymeric materials to depolymerization treatment comprising at least treatment with hydrogen, so as to form at least first fraction having liquid or solid alkanes and second fraction including at least gaseous, hydrocarbons; and (b) introducing hydrocarbons contained in the second fraction into catalytic decomposition of hydrocarbons into hydrogen and carbon. USE - The process is useful for treating polymeric materials e.g. polyolefinic in co-producing hydrogen (all claimed). ADVANTAGE - The process: allows net hydrogen production and high yield of liquid or solid alkanes while avoiding co-producing substantial amount of greenhouse or toxic gases; allows to realize synergies of the overall energy consumption; and minimize separation operations and optimizing heat recovery. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for co-producing hydrogen comprising carbon and liquid, and/or solid alkanes.