製備鈀金屬陶瓷複合膜應用於高溫氫氣與二氧化碳分離

Abstract

本研究藉由混合鈀金屬及質導陶瓷(BaCe0.4Zr0.4Gd0.1Dy0.1O3-x; BCZGD)粉末，經球磨壓碇，於1450度空氣環境下燒結24小時後成功製備出一種金屬陶瓷複合材料。此材料在氫氣與二氧化碳混合環境中展現了優異的氫氣滲透能力。此材料性質透過掃描式電子顯微鏡 (SEM)、X光繞射分析儀 (XRD)及熱重分析儀 (TGA)做鑑定分析； XRD顯示除了鈀金屬與質導陶瓷之特徵峰外，試片燒結前後並無其它明顯之雜相生成；TGA也證實了材料對CO2有良好之化學穩定性；透氫測試部分，藉由氣相層析儀量測攝氏溫度400到700度間不同氫氣濃度梯度下此材料所滲透之氫氣流量，另外在氫氣與二氧化碳混和比例一比一的情況下，此材料能完全分離氫氣與二氧化碳，分離係數比趨近無窮大，並同時具有每分鐘每平方公分1.25毫升之氫氣滲透流量。

A cermet composite consisting of palladium and BaCe0.4Zr0.4Gd0.1Dy0.1O3-x (BCZGD) is fabricated by mixing palladium and BCZGD powders in a ball mill, followed by pressing and sintering at 1450°C for 24 h in air. The Pd-BCZGD cermet demonstrates impressive hydrogen permeation flux in a mixture of hydrogen and carbon dioxide at elevated temperature. Material characterization including scanning electron microscopy (SEM), X-ray diffraction (XRD), and thermo-gravimetric analysis (TGA) are performed. XRD patterns indicate pure phases of fcc palladium and perovskite BCZGD. SEM images and element mapping suggest a homogeneous mixture of cermet without noticeable defect and phase segregation. TGA results confirm stability of the cermet against carbon dioxide without chemical decomposition. The hydrogen permeation flux is determined via a gas chromatography from 400 to 700°C at various hydrogen concentration gradients. We record a hydrogen flux of 1.25 cm3 min-1 cm-2 in 50% hydrogen and 50% carbon dioxide at 700°C, with a selectivity of H2/CO2 approaching infinity.