Direct conversion of methane to C2 hydrocarbons using W supported on sulfated zirconia solid acid catalyst

Abstract

One of the most challenging aspects of modern day catalysis is the activation of methane. Conventionally, methane is activated with oxidizing agents to produce syngas, which then reacts to produce high value hydrocarbons. This process is energy inefficient. A more economic process is the direct one-step activation of methane to form value-added chemicals. This report focuses on direct conversion of methane to ethylene and ethane. Ethylene and ethane are the most important feedstocks in modern day chemical industries. Conventional process for ethylene production is via steam cracking of hydrocarbons, which is not an energy efficient approach. A direct conversion route from methane to C2 hydrocarbons would be a significant advance and has been widely studied. Mo supported on solid acids have been previously reported to be promising for direct conversion of methane to higher hydrocarbons. Here, a novel catalytic approach is introduced with W, a strong oxidizing agent, doped on sulfated zirconia solid acid and studied for the activation of methane at 650–750 °C. BET, DRIFTS, ammonia TPD, XPS, XRD and SEM–EDX were used to characterize the fresh catalyst. Reaction products are primarily ethylene and ethane, along with trace aromatics. Methane activation along with production of C2 hydrocarbons increased noticeably at higher temperature but deactivated due to carbon deposition as confirmed by TPO.