Tandem Nonoxidative Coupling of Methane and Carbon Dioxide Reduction via Pulsed Joule Thermochemistry

The conversion of CH 4 into higher hydrocarbons and CO 2 reduction are promising yet hindered by poor selectivity and the cost of green H 2 . Methane can act as an intrinsic H 2 donor for CO 2 reduction, but its activation typically leads to dry reforming to syngas at high temperatures. Here, we demonstrate that rapid pulsed Joule heating (RPH) of CH 4 /CO 2 mixtures enables the direct nonoxidative coupling of methane to C 2 hydrocarbons (acetylene and ethylene) while simultaneously reducing CO 2 via the reverse water-gas shift reaction. Compared to continuous Joule heating, RPH achieves higher CH 4 conversion at lower average temperatures, requires 60% less power, and enhances carbon element stability by suppressing the reverse Boudouard reaction. Kinetic modeling reveals that RPH’s microsecond pulses favor C–C coupling over reforming and aromatization due to time scale separation. This strategy can also convert biogas directly into intermediates for C 3+ oxygenates, bypassing the energy-intensive dry reforming process.