Protonic ceramic cells with thin BaZr0.8Y0.2O3-δ electrolytes for stable separation of H2 from H2–CO2 mixtures

Here we report selective separation of high-purity H2 from a CO2-containing stream using protonic ceramic cells with thick Ni–BaZr0.1Ce0.7Y0.2O3-δ cathode substrates, thin BaZr0.8Y0.2O3-δ electrolytes and thin Ni–BaZr0.8Y0.2O3-δ anodes, as fabricated by the tape casting and tape lamination methods. Scanning electron microscopy observations show an overall micron porous structure for both electrodes with some nano-scale porosities inside Ni particles. The measured H2 flux out of 3%-humidified 10% H2 – 90% CO2 at 700°C was 3.2 ml•cm−2•min−1 at 0.90 V with a Faraday's efficiency of 97.8%. A preliminary 50-hour measurement in 10% H2 – 90% CO2 shows a slight increase in the pumping voltage from 0.96 to 1.03 V with a constant H2 flux of 6.5 ml•cm−2•min−1 and Faraday's efficiencies continuously above 97%, as enabled by excellent stability of BZY against CO2.