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

Abstract

Here we report selective separation of high-purity H 2 from a CO 2 -containing stream using protonic ceramic cells with thick Ni–BaZr 0.1 Ce 0.7 Y 0.2 O 3-δ cathode substrates, thin BaZr 0.8 Y 0.2 O 3-δ electrolytes and thin Ni–BaZr 0.8 Y 0.2 O 3-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 H 2 flux out of 3%-humidified 10% H 2 – 90% CO 2 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% H 2 – 90% CO 2 shows a slight increase in the pumping voltage from 0.96 to 1.03 V with a constant H 2 flux of 6.5 ml•cm −2 •min −1 and Faraday's efficiencies continuously above 97%, as enabled by excellent stability of BZY against CO 2 . • Protonic ceramic cells with thin BaZr 0.8 Y 0.2 O 3-δ electrolytes are fabricated. • Ni–BaZr 0.8 Y 0.2 O 3-δ anodes show promise for stable operation in 10%H 2 –90%CO 2 . • The H 2 recovery rate from 10%H 2 –90%CO 2 is 3.2 ml•cm −2 •min −1 at 1.5 V.