Co-production of Few-layer Graphene and Hydrogen from Methane Pyrolysis Based on Cu and Metal Oxide-KCl Molten Medium

Methane pyrolysis is a technology that utilizes fossil energy to produce high added value carbon materials and hydrogen. However, traditional methods, such as chemical vapor deposition (CVD) and molten metal catalysis, face challenges in the production of graphene, including catalyst deactivation, difficulty in separating graphene from the catalyst, and high reaction temperatures (>= 1100 degrees C), which limit their industrial applications. This study proposes an innovative approach to produce graphene by catalyzing methane pyrolysis using Cu and metal oxides-KCl molten medium. By adding metal oxides (Al2O3, TiO2, ZrO2, MgO, SiO2) as dispersants, the dispersion of active Cu sites is enhanced. Notably, Cu/ZrO2 with a Cu content of 50% (in volume) and Cu/MgO with a Cu content of 75% (in volume) catalysts enable the efficient production of few-layer graphene. Cu/ZrO2 catalyst with a Cu content of 50% (in volume) exhibits the highest activity, achieving a methane conversion rate of 22%, a hydrogen production yield of 21.5 mmol/h, and formation of large-area and smooth few-layer graphene. This study provides a new technical route for co-production of graphene and hydrogen via methane pyrolysis, offering potential for large-scale graphene production in the future.