Enhanced catalytic hydrogenolysis of natural rubber to natural gas over Ru/ZrO2 via phase control strategy

The inert C=C and C-C bonds is a major limitation for the degradation and utilization of rubber wastes, which has resulted in the increasingly serious environmental crisis. Here we developed an efficient strategy to catalyze complete cleavage of C=C and C-C bonds in natural rubber by the enhanced reaction activity of Ru-based catalysts with the modulated ZrO2 crystal phases. And 95.0% of gas carbon yield with 98.6 mol% of CH4 and 1.4 mol% of C2-C4 hydrocarbons was achieved over Ru/m-ZrO2, which was more than 3 times higher than gas carbon yield over Ru/c-ZrO2 and Ru/t-ZrO2. The investigation on reaction pathway displayed that the primary hydrogenation of C=C bonds with high bond energy would promote the transformation of natural rubber. The Ru-0 species and spill-over hydrogen in Ru/m-ZrO2 catalyst acted in synergy for the catalytic hydrogenolysis of natural rubber. Ultimately, various rubber wastes were directly converted to natural gas, it could provide a new perspective for the chemical upcycling of the accumulated rubber wastes.