BaCe0.4Zr0.4Gd0.1Dy0.1O3-δ質導陶瓷薄膜之導電度及化學穩定性研究

Abstract

本研究利用反應前驅物Ba(NO3)2, Ce(NO3)3‧6H2O, ZrO(NO3)4‧6H2O, Gd(NO3)3‧6H2O, Dy(NO3)3‧5H2O與適量甘胺酸以燃燒法製備質導陶瓷BaCe0.4Zr0.4Gd0.1Dy0.1O3-x，在1300℃下持溫十小時鍛燒成粉末，之後以440 MPa壓力壓成生胚，於1600℃下燒結24小時，製成薄膜。利用XRD、SEM、EDS及TGA對材料進行分析。以XRD確認其成相狀況，確定材料具有Perovskite結構，再經由TGA確認其二氧化碳之化學穩定性；在薄膜部分，由SEM確認薄膜緻密性、EDS確認組成、XRD確認結構成相狀況，並做TGA確認二氧化碳化學穩定性。 在導電性部分，可以得到材料的導電度在700℃含有飽和水蒸汽的空氣下為3.24×10-3 (S cm-1)，活化能為0.53 eV，在含有飽和水蒸汽的氫氣下則是1.35×10-3 (S cm-1)，活化能為0.29 eV。.

We demonstrate the preparation of BaCe0.4Zr0.4Gd0.1Dy0.1O3-δ (BCZGD) via a wet chemical route using precursors such as Ba(NO3)2, Ce(NO3)3‧6H2O, ZrO(NO3)4‧6H2O, Gd(NO3)3‧6H2O, and Dy(NO3)3‧5H2O. The synthetic process involves the dissolution of relevant precursors and glycine in deionized water at proper molar rations. Subsequently, the mixture undergoes a heat treatment at 1300°C for 10 hr in air to form the perovskite powders. The as-synthesized BCZGD powders are filtered and pressed at 440 MPa, followed by sintering at 1600°C for 24 hr in air to render a free-standing proton-conductive disk with a thickness of 500 μm. Material characterizations including scanning electron microscopy (SEM), X-ray diffraction (XRD), thermo-gravimetric analysis (TGA), and electrical conductivity measurements are performed. Diffraction patterns from the XRD indicate a perovskite structure without the appearance of undesirable phases. The electrical conductivity is recorded iii at 3.24×10-3 Scm-1 at 700°C in wet air with an activation energy of 0.37 eV. In a wet H2 atmosphere at identical temperature, its conductivity becomes 1.35×10-3 Scm-1 with an activation energy of 0.29 eV. Results from TGA analysis confirm that the BCZGD is chemically stable against CO2. Currently, the BCZGD samples are subjected to rigorous evaluations for their performances as a high-temperature membrane to separate CO2 and H2 for integrated gasification combined cycle (IGCC) power generation plant.