Coupling catalysis and electrocatalysis for hydrogen production in a solid electrolyte membrane reactor

• Coupling catalysis and electrocatalysis for H2 production.
• Double-chamber solid electrolyte cell configuration allows to regenerate a catalyst.
• In situ valorization of the produced carbon in the steam electrolysis process.
• C2s hydrocarbons can be additionally produced during the regeneration of the catalyst.
• The stability and reproducibility of the system was proved through 18 cycles.

This study reports the production of H2 via catalytic methane decomposition on Pt supported on yttria-stabilized zirconia together with its electrochemical regeneration in a solid electrolyte membrane reactor. Hence, a Pt-YSZporous/YSZ/Pt double-chamber solid electrolyte cell was prepared and tested under two reaction regimes. In the first regime, under open-circuit conditions, hydrogen and carbon are produced on the catalytically active Pt-YSZ porous catalyst via methane decomposition reaction (CH4 (g) → C (s) + 2H2 (g)). In the second regime, under polarization conditions, steam is electrolyzed at the Pt cathode of the cell (H2O + 2e− → H2 + O2−) and the produced O2− ions were simultaneously electrochemically pumped to the Pt/YSZ porous catalyst (anode), thereby allowing removal of the previously deposited carbon (C (s) + O2− → CO2 (g)) and finally regenerating the Pt/YSZ porous catalyst film. We demonstrated that the carbon generated in the methane decomposition step serves as a depolarizating agent in the steam electrolysis process, thus decreasing the electrical energy input required for electrochemically producing pure H2. In addition, during the regeneration step, C2 hydrocarbons (e.g., ethane and ethylene) were obtained as a result of the electrocatalytic methane oxidative coupling on the Pt/YSZ porous catalyst film. The performance and durability of the system was also verified for long operation times in view of the possible practical application of this novel reactor configuration, which combines gas-phase catalysis and electrocatalysis for hydrogen production.

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