Catalytic decomposition of hydrous hydrazine to hydrogen over oxide catalysts at ambient conditions for PEMFCs

摘要

Hydrous hydrazine is a hydrogen carrier in liquid state at room temperature, having high hydrogen content, and free of CO and other carbon-containing gases. In this study, the effects of oxides properties on the initial catalytic activity towards hydrous hydrazine decomposition as hydrogen source for proton exchange membrane fuel cells (PEMFCs) were systematically investigated. The results showed that the perovskite structure, cobalt ion and oxygen nonstoichiometiy of oxides have important influence on the catalytic decomposition of hydrous hydrazine. The hydrogen selectivity of Ba_(0.5)Sr_(0.5)CO_(0.8)Fe_(0.2)O_(3-δ) (BSCF), SrCoO_(3-δ) (SC) and La_(0.2)Sr_(0.8)CoO_3_8 (LSC2) catalysts with KOH promoter for hydrous hydrazine decomposition was compared at 55 ℃, which indicated that hydrogen selectivity of BSCF and LSC2 could reach 100%. The performance of a PEMFC operating on the decomposition products from hydrous hydrazine was also studied and compared with that operating on pure hydrogen. The cell delivered a peak power density of 510 mW cm~(-2) at 50 ℃ by operating on the gaseous decomposition products of hydrous hydrazine, which was only slightly lower than that of a similar cell with pure hydrogen as fuel, due to the diluting effect of nitrogen. It highly promises hydrous hydrazine as a indirect fuel of PEMFCs for portable application.