BCTZ/Ni-BCTZ Dual-layer Hollow Fiber Ceramic Membrane For Hydrogen Permeation And Fuel Cell Performance

Hydrogen（H₂）-selective proton-conducting perovskite membrane is considered as an alternative of palladium membrane due to the low cost,high hydrogen permeability and high-temperature resistance.BaCeO₃-based ceramic is one of the most widely studied proton conductors.However,its application is limited because of its low proton conductivity and poor tolerance of CO₂.In this work,we use sol-gel method to synthesis A-site deficient Zr-doped proton-conducting Ba_0.95Ce_0.85Tb_0.05Zr_0.1O_3-δ（BCTZ）ceramics powder.Dual-layer BCTZ/NiO-BCTZ hollow fiber membrane is prepared via co-spinning and co-sintering technology to improve the hydrogen permeability and stability.Dual-layer BCTZ/NiO-BCTZ membrane is sintered at 1450℃ with good thermal matching and no delamination or peeling.After reduction,BCTZ/Ni-BCTZ hollow fiber consists of porous inner layer Ni-BCTZ and dense outer layer BCTZ,with thickness of 14μm.The presence of Zr⁴⁺in BCTZ perovskite lattice shows a higher CO₂ resistance for BCTZ than that for Ba_0.95Ce_0.95Tb_0.05O_3-δ（BCT）using CO₂-temperature programmed desorption.When the pure nitrogen with the flow rate of 110mL·min^-1was used as sweeping gas,Hydrogen permeation flux of dual-layer BCTZ/Ni-BCTZ hollow fiber reached about 0.41 mL·min^-1·cm^-2at900^oC.When CO₂ was introduced in the permeate side,H₂ permeation flux was enhanced comparing with the CO₂-absent case,which was attributed to the presence of reverse water-gas shift reaction that consumed the permeated H₂.With the 7vol%CO₂-containing N₂ as a sweeping gas with a flow rate of 80 mL·min^-1,H₂ permeation flux of dual-layer BCTZ/Ni-BCTZ hollow fiber improved 10%.In CO₂ atmosphere,the prepared hollow fiber is stable for 600 hours without microstructure variation,highlighting its potential use for H₂ separation in CO₂-containing reactions and processes.The silver as the cathode is coated on the outer of dual BCTZ/Ni-BCTZ hollow fiber ceramic membrane to assemble the proton-conducting solid oxide fuel cell with the configuration of Ag/BCTZ/Ni-BCTZ.With H₂ as fuel with a flow rate of 40 mL·min^-1,the open circuit voltage is up to 1.15V,which indicates the dense electrolyte layer BCTZ.At 700°C,the maximum power density is just 80mW·cm^-2,due to the incomplete current collection,which would be improved in the future work.