Oxygen vacancy, permeability and stability of Si doping Pr0.6Sr0.4FeO3-δ ceramic membrane for water splitting

The high-valence inorganic metalloid element of silicon was used for doping perovskite type oxides Pr0.6Sr0.4Fe1-xSixO3-delta (PSFSix, x = 0-0.1), as the oxygen transport membranes (OTM) for thermochemical water splitting to hydrogen production, which were fabricated by sol-gel method successfully. The effects of Si doped on microstructure, thermal expansion, permeability, and stability were investigated systematically. Although the crystal structure does not change, the metal-oxygen average binging energy (ABE) and oxygen vacancy concentration at room temperature increase after Si4+ doped. Furthermore, the phase transition process is reduced below the operating temperature by silicon doped. Due to the increase of ABE, the oxygen vacancy concentration of PSF exceeds that of the Si-doping samples with the temperature elevated. This is why the oxygen permeation flux of Si-doping samples is gradually exceeded by PSF. The long-term stability of water splitting to hydrogen is enhanced because the Si-doping increases the chemical stability of samples in reducing atmosphere.

Automated summary

The study found that doping silicon can improve the stability and oxygen permeation flux of oxygen transport membranes, reduce the phase transition temperature, increase the oxygen vacancy concentration, thus enhancing the long-term stability of hydrogen production through water splitting.