Microwave-Enhanced Methane Decomposition over Promoted Carbon Catalysts for Sustainable Hydrogen and Carbon Nanomaterial Production

High Resolution Image Download MS PowerPoint Slide Methane decomposition is emerging as a critical technology for producing CO 2 -free H 2, a cornerstone for the deep decarbonization of energy systems. Electrifying this process through microwave-assisted catalysis introduces a transformative sustainability advantage by enabling direct, selective energy delivery to the catalyst, minimizing thermal inefficiencies, and unlocking compatibility with renewable electricity. Here, we demonstrate that activated carbon catalysts under microwave irradiation achieve efficient methane activation at temperatures far below those required in conventional thermal systems. At 500 °C, methane conversion reached 80% with complete selectivity toward hydrogen, revealing a strong microwave−carbon synergy that accelerates reaction kinetics. The resulting carbon deposits exhibited tunable morphologies, ranging from amorphous coatings to nanocubes and nanofibers. By controlling the operating conditions, microwave-assisted methane decomposition enabled the simultaneous production of functional carbon nanomaterials. The catalytic performance was further enhanced by earth-abundant metal promoters: alkali metals improved catalyst stability and hydrogen desorption, while Fe delivered the highest conversions and directed the growth of thin graphitic layers on nanoparticles and the carbon support. When benchmarked against conventional thermal decomposition, the Fe/C catalyst exhibited a boost in methane conversion from ∼50 to ∼75% when operated under microwave irradiation, highlighting the benefits of this operation. These findings establish microwave-driven methane decomposition as a platform for low-temperature, electrified hydrogen production coupled with precision synthesis of carbon nanostructures, advancing scalable, sustainable catalytic processes for H 2 production based on inexpensive, widely available materials.