1. Field
A hydrogen separation membrane and a hydrogen separation device including the hydrogen separation membrane are disclosed.
2. Description of the Related Art
A hydrogen separation membrane selectively separates hydrogen gas from a gas mixture including hydrogen gas, and is applied for producing high purity hydrogen or the like. For example, when methane gas is modified, hydrogen (H2) and carbon dioxide (CO2) gasses are produced. By passing the mixed gas through the hydrogen separation membrane, high purity hydrogen may be obtained since carbon dioxide is not passed through the separation membrane, and only hydrogen gas is passed.
A polymer, a ceramic, a metal, or the like has been developed for a material for a hydrogen separation membrane. Among them, the metal hydrogen separation membrane has high selectivity to hydrogen and thus can provide ultrahigh purity hydrogen. The ultrahigh purity hydrogen separated through the metal hydrogen separation membrane has a merit of being directly applied to a polymer electrolyte fuel cell or the like.
The polymer electrolyte fuel cell uses a platinum catalyst for oxidizing the hydrogen gas into hydrogen ions. As the platinum catalyst is easily poisoned by carbon monoxide (CO), if that occurs, the fuel cell performance is remarkably deteriorated. Accordingly, when using the ultrahigh purity hydrogen produced with the metal hydrogen separation membrane, the platinum catalyst may be prevented from being poisoned by carbon monoxide, and the polymer electrolyte fuel cell may be driven at high efficiency and for a long time.
Since hydrogen may permeate through the metal hydrogen separation membrane by dissociating hydrogen molecules in the inlet surface, diffusing hydrogen atoms in the metal, and recombining hydrogen atoms in the outlet surface, the hydrogen decomposition/recombination catalyst characteristics of the metal separation membrane surface and the inner crystal structure of the metal separation are of interest. Since the high hydrogen permeation characteristics of palladium (Pd) were reported, palladium (Pd)-based hydrogen separation membranes have been much studied (see, for example, S. Yun et al., J. Membr. Sci. 375, 2011, 28-45, the content of which is incorporated herein by reference in its entirety). Nonetheless, there remains a need for an improved hydrogen separation membrane.