Proton solid oxide electrolytic cell facilitates non-oxidized dehydrogenation of ethane

Ethylene is an important petrochemical raw material. Its output is a symbol of a country's petrochemical production capacity and level. Due to the oxidation and dehydrogenation of ethane, it is difficult to control the oxidation degree, and the side reactions mostly make ethylene less selective.

In a study published in ACS Catalysis, a research group led by Prof. XIE Kui from Fujian Institute of Research on the Structure of Matter (FJIRSM) of the Chinese Academy of Sciences reported a coupled system in which a new process of non-oxidized dehydrogenation of ethane to ethylene was realized in proton conductive solid oxide electrolytic cell.

The researchers found that ethane was electrocatalyzed to ethylene and protons (C₂H₆→ C₂H₄ + 2H⁺ + 2e^-) at the anode, and the protons were "extracted" by electrolyte to the cathode to form hydrogen (2H⁺ + 2e^-→ H₂). When CO₂ and proton react at the cathode, CO (CO₂ + 2H⁺ + 2e^-→ CO + H₂O) is generated. CO₂ is reduced to CO fuel, and the overpotential between the two electrodes is reduced, thus the dehydrogenation efficiency of ethane is greatly improved.

Electrochemical "extraction" of protons achieves efficient non-oxidative dehydrogenation of ethane to ethylene. At atmospheric pressure, 700℃ and 0.8 V, the conversion rate of ethane is up to 75.2%, the selectivity of ethylene is ～100%, and the performance of 100 hours of operation is not attenuating.

Besides, experimental and theoretical results revealed that by doping Nb_1.33(Ti_0.8Mn_0.2)_0.67O4-δ (NTMO) and riveting the growth nanometer Ni_xCu1_-x alloy on the surface in situ, and the metal-oxide interface system was constructed to enhance the electrocatalytic activity and carbon deposition resistance of ethane conversion.

This novel electrocatalytic process realized not only the non-oxidation dehydrogenation of ethane to ethylene, but also the reduction and high value utilization of CO₂, which has economic and sustainable development potential. This study provides an efficient and reliable electrochemical method for the conversion of C₂H₆, and paves a new way for the conversion of other alkanes.