Electrochemical hydrogen separation through a F-doped proton-conducting membrane at intermediate temperatures

The development of efficient H 2 separation technology at intermediate temperatures (300~500 °C) is crucial for bridging the gap between upstream H 2 production (e.g., the water-gas shift reaction) and downstream utilization (e.g., ammonia synthesis) processes. Herein, a fluorine (F)-doping strategy is developed to enhance the proton conductivity of the BaZr 0.1 Ce 0.7 Y 0.1 Yb 0.1 O 3-δ membrane material. F incorporation into the oxygen lattice sites effectively weakens the metal–oxygen bonds and increases the concentration of oxygen vacancies, thereby improving the proton conductivity of the optimized BaZr 0.1 Ce 0.7 Y 0.1 Yb 0.1 O 3-δ F 0.1 (BZCYYbF 0.1 ) membrane. A high-efficiency F-doped electrochemical H 2 pump (EHP) with the configuration Ag-Pd|BZCYYbF 0.1 |BZCYYbF 0.1 -Ni is constructed for H 2 separation at intermediate temperatures. The constructed F-doped EHP exhibits excellent H 2 separation performance with a maximum H 2 permeation flux of 2.25   mL·min -1 ·cm -2 at a current density of 300   mA·cm -2 and near-100% Faradaic efficiency during various mixed-gas separation processes, which is much superior to that of state-of-the-art mixed protonic–electronic conducting membranes operating at 700~1000  °C. This study demonstrates the technical feasibility and high efficiency of EHPs for H 2 separation driven by electrical energy and offers an effective strategy to enhance the performance of EHPs at intermediate temperatures.