Hydrogen separation from syngas using high-temperature proton conductors

Abstract

Hydrogen pumps using high-temperature proton conductors have been examined as a candidate means of hydrogen separation from syngas. Durability to CO 2 is a main concern for the alkali-earth-containing perovskites and was tested for a few typical compositions. Ce-excluded and cerate-zirconate solid solution electrolytes, SrZr 0.9 Y 0.1 O 3-α , and BaCe 0.6 Zr 0.3 Nd 0.1 O 3-α were stable in CO 2 -containing atmospheres, whereas they showed poor overpotential characteristics when platinum electrodes were used. It is demonstrated that the hydrogen pumping properties can be much improved for the case of SrZr 0.9 Y 0.1 O 3-α by the use of palladium anode and SrCe 0.95 Yb 0.05 O 3-α interlayer for the cathode.

Thermionic emission of protons across a grain boundary in 5 mol% Y-doped SrZrO3, a hydrogen pump

“…fuel cell applications, mainly because they possess exceptionally high conductivity in particular at relatively low temperatures (300e600 C) [2,5e9]. These materials also offer a great potential for gas sensors [10,11] and hydrogen pumps [12,13].…”

Performance of palladium electrode for electrochemical hydrogen pump using strontium-zirconate-based proton conductors

“…The experimental apparatus is the same as that described elsewhere [2,3,5,7]. The samples were fixed between alumina tubes with glass gaskets, separating the two electrode compartments (Fig.…”

“…So far, we have investigated a hydrogen separation method by electrochemical hydrogen pumps using high temperature proton conductors [1][2][3][4][5][6][7]. The schematic illustration of the electrochemical hydrogen pumps is shown in Fig.…”

“…In addition, the zirconate-based oxides have a high mechanical strength, which is also an attractive feature for practical use. Therefore, recently, we have mainly investigated the hydrogen pumps using the zirconate-based oxides [2,3,5,7].…”

Electrical conductivities of strontium-doped rare earth ultraphosphates and oxyphosphates

“…However, some of the proton conducting ceramics developed earlier, i.e. cerates, are highly reactive to ambient gases such as carbon dioxide and/or water vapor [30][31][32][33][34][35], since they contain alkaline earth metals as a main component. Thus, one of the important scientific and technological challenges is to let the ceramics have high chemical stabilities against the abovementioned gas species while having high protonic conductivity.…”